HSchwenk_Web.de wrote:
> I would like to calculate the position of the sun, only
> depending, on my position an the earth, and depending, on the date and time.
For actual code, "Astronomical Algorithms", Jan Meeus.
Mr. Meeus is Belgian - It would surprise me if there
is not a German edition. The book is a classic.
This is the U.S. Naval Observatory site. They have great software to allow
you to calculate many things. This place will allow you to choose the time
interval for the position of the sun for any place on earth for one day. it
will give the altitude and azimuith of the sun for your location.
If you have access to an analemma you can use this formula to calculate the
sun's noon altitude. Sun altitude = ((90 degrees - your latitude) +
declination of the sun on a specific date The analemma will give you the
declination of the sun on every day of the year. You should be able to get
it on the net, or I can give you the info.
For the upcoming vernal equinox, the sun's declination will be 0 degrees
(sun rays directly on the equator). At my latitude 40 degrees N, the sun
will reach a peak of 50 degrees above my horizon. On the first day of
winter it is a pitifull 26.5 degrees and the first day of summer it is at
73.5 degrees!
If you need more info, give me your latitude and longitude, the time
interval you would like, and the days you wish and I will run software I
have to calculate the sun's altitude and azimuth for your location. I
should be able to give it to you as plain ASCII text, a Microsoft Word
document, or in a Microsoft Excel spreadsheet. Let me know if you would
like me to run the info, and what format would be best for you. I can send
it to your e-mail address as an attachement.
Rick
Original Message
From: "HSchwenk_Web.de" <HSchwenk@w...>
To: <basicstamps@yahoogroups.com>
Sent: Wednesday, December 10, 2003 3:12 PM
Subject: Re: [noparse][[/noparse]basicstamps] Re: sun tracker
> Hi Rick and group
>
>
>
> Your "two cents" are interesting!
>
> they give help in my project. (playing with solar panels)
>
>
>
> I would like to calculate the position of the sun, only
>
> depending, on my position an the earth, and depending, on the date and
time.
>
> I have an RF atomic time receiver (for Germany), 2 stepper motors and a
stamp.
>
> The clock with the stamp und the steppers work fine, but I have problems
with the
>
> calculations of the position of the sun.
>
> Do You know the formula, or a link, or a similar project,
>
> or even an pbasic program?
>
>
>
> It would make it easier for me
>
>
>
> Regards Heinz
>
>
>
>
>
>
>
>
>
Original Message
>
> From: Richard C. Walter Jr.
> To: basicstamps@yahoogroups.com
> Sent: Wednesday, March 10, 2004 2:46 AM
> Subject: Re: [noparse][[/noparse]basicstamps] Re: sun tracker
>
>
> I thought I would throw my two cents into the array (sorry for the pun).
>
> The earth actually turns about 361 degrees per day. It would be easier
to
> explain with a diagram but here goes. Since the earth rotates on its
axis
> and revolves around the sun, the earth must turn a little more than 360
> degrees per day to play "catch up" to the sun. If you think of the
earth
> moving in its orbit aorund the sun, it moves around 1 degree per day
(360
> degrees in 365 days). Since the earth moved through space about 1
degree,
> it must turn on its axis an extra degree (361) to point back to the sun.
>
> In other words, if you had a sundial on the earth indicating it is noon,
the
> earth would turn about 361 degrees to have the sundial say it is noon
again.
> This is one reason why we have the equation of time. (The difference
between
> clock time and sundial time). The sun runs "fast" and "slow" at
different
> times during the year because the of the earth turning (rotating) a
> different amount than 360 degrees per day.
>
> Also, at the solstices, the sun appears to move parallel to the ecliptic
> (sun's path on the celestial sphere) so the sun moves a greater distance
> eastward per day. At the equinoxes, the sun's path is more of a right
angle
> to the ecliptic (sun is moving above or below the celestial equator) so
it
> does not move as far eastward as other times of the year.
>
> Look for "analemma" with google and check out the very good
explainations
> regarding this process. The analemma is a figure 8 that show the
equation of
> time on the X axis and the declination of the sun (or the latitude of
sun's
> rays 90 degrees overhead) for each day of the year on the Y axis. It
used
> to be commonly found on old maps and globes in the Pacific Ocean where
there
> was nothing but water!
>
> Finally, since we call one day (24 hours) the time it takes from sunrise
to
> sunrise it does not matter if it is 360 or 361 degrees. Everyone is
correct
> about the sun moving 1 degree every 4 minutes, but you must remember
that is
> an average.
>
> If you want to refer to a day as the time it takes the earth to turn
exactly
> 360 degrees, we are talking about a sidereal day (star time). A
sidereal
> clock runs faster than a "sun" clock (like on the wall). A sidereal day
is
> approx. 23 hours, 56 minutes, and 4.09 seconds.
>
> If you view a star above a branch of a tree tonight at 9 PM (on your
regular
> clock) and go out each night at 9 PM, the star will continually move
away
> from the branch. If you went out at 9 hours on your sidereal clock each
> night, the star will be in the exact same position relative to the tree,
> night after night.
>
> By the way, solar clocks (wall clocks) and sidereal clocks agree on one
day,
> the autumnal equinox.
>
> Sorry you got me started. I'll crawl back in my hole and lurk another 3
or
> 4 years.
>
> Rick
>
>
>
>
> To UNSUBSCRIBE, just send mail to:
> basicstamps-unsubscribe@yahoogroups.com
> from the same email address that you subscribed. Text in the Subject
and Body of the message will be ignored.
>
> Yahoo! Groups Links
>
>
>
>
>
>
> [noparse][[/noparse]Non-text portions of this message have been removed]
>
>
>
> To UNSUBSCRIBE, just send mail to:
> basicstamps-unsubscribe@yahoogroups.com
> from the same email address that you subscribed. Text in the Subject and
Body of the message will be ignored.
>
> Yahoo! Groups Links
>
>
>
>
>
Many years ago I wrote a Turbo Pascal (or maybe it was Power Basic)
program that calculates sun azimuth and elevation for any latitude,
longitude, date and time. I don't remember if height above sea level
was considered too. The results were within 1 or 2 degrees compared to
almanac values. I doubt if the program can practically be translated
into pbasic for stamp usage, but if you are interested, I'll try to find
it.
they give help in my project. (playing with solar panels)
I would like to calculate the position of the sun, only
depending, on my position an the earth, and depending, on the date and
time.
I have an RF atomic time receiver (for Germany), 2 stepper motors and a
stamp.
The clock with the stamp und the steppers work fine, but I have problems
with the
calculations of the position of the sun.
Do You know the formula, or a link, or a similar project,
or even an pbasic program?
It would make it easier for me
Regards Heinz
Original Message
From: Richard C. Walter Jr.
To: basicstamps@yahoogroups.com
Sent: Wednesday, March 10, 2004 2:46 AM
Subject: Re: [noparse][[/noparse]basicstamps] Re: sun tracker
I thought I would throw my two cents into the array (sorry for the
pun).
The earth actually turns about 361 degrees per day. It would be
easier to
explain with a diagram but here goes. Since the earth rotates on its
axis
and revolves around the sun, the earth must turn a little more than
360
degrees per day to play "catch up" to the sun. If you think of the
earth
moving in its orbit aorund the sun, it moves around 1 degree per day
(360
degrees in 365 days). Since the earth moved through space about 1
degree,
it must turn on its axis an extra degree (361) to point back to the
sun.
In other words, if you had a sundial on the earth indicating it is
noon, the
earth would turn about 361 degrees to have the sundial say it is noon
again.
This is one reason why we have the equation of time. (The difference
between
clock time and sundial time). The sun runs "fast" and "slow" at
different
times during the year because the of the earth turning (rotating) a
different amount than 360 degrees per day.
Also, at the solstices, the sun appears to move parallel to the
ecliptic
(sun's path on the celestial sphere) so the sun moves a greater
distance
eastward per day. At the equinoxes, the sun's path is more of a right
angle
to the ecliptic (sun is moving above or below the celestial equator)
so it
does not move as far eastward as other times of the year.
Look for "analemma" with google and check out the very good
explainations
regarding this process. The analemma is a figure 8 that show the
equation of
time on the X axis and the declination of the sun (or the latitude of
sun's
rays 90 degrees overhead) for each day of the year on the Y axis. It
used
to be commonly found on old maps and globes in the Pacific Ocean where
there
was nothing but water!
Finally, since we call one day (24 hours) the time it takes from
sunrise to
sunrise it does not matter if it is 360 or 361 degrees. Everyone is
correct
about the sun moving 1 degree every 4 minutes, but you must remember
that is
an average.
If you want to refer to a day as the time it takes the earth to turn
exactly
360 degrees, we are talking about a sidereal day (star time). A
sidereal
clock runs faster than a "sun" clock (like on the wall). A sidereal
day is
approx. 23 hours, 56 minutes, and 4.09 seconds.
If you view a star above a branch of a tree tonight at 9 PM (on your
regular
clock) and go out each night at 9 PM, the star will continually move
away
from the branch. If you went out at 9 hours on your sidereal clock
each
night, the star will be in the exact same position relative to the
tree,
night after night.
By the way, solar clocks (wall clocks) and sidereal clocks agree on
one day,
the autumnal equinox.
Sorry you got me started. I'll crawl back in my hole and lurk another
3 or
4 years.
Rick
To UNSUBSCRIBE, just send mail to: basicstamps-unsubscribe@yahoogroups.com
from the same email address that you subscribed. Text in the Subject
and Body of the message will be ignored.
Yahoo! Groups Links
[noparse][[/noparse]Non-text portions of this message have been removed]
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and Body of the message will be ignored.
Hi Dave, Rick, Dov, Jack and.....
thanks for Your quick answers
Dave
Your program is exactly what I am looking for. I don't understand Turbo Pascal,
but know somebody who may help me. Also, If You have the calculation in usual
math, I may have the chance to make my stamp to do the job......
I would like that my stamp calculate first the azimuth and elevation and then
calculate the steps for my two step motors to move to.
In my program I like to use the time and date the latitude and longitude.
As I don't need high angel resolution I can ignore the height above sea level
and may be simplify the calculation too.
Rick
How did You calculate This?: "peak of 50 degrees above my horizon. On the first
day of
winter it is a pitifull 26.5 degrees and the first day of summer it is at 73.5
degrees"
...................................................................
The U.S. Naval Observatory site is interesting and the link there to the Geonam
Query page too.
My LATITUDE is 50° 04' 00" N
My LONGITUDE is 007° 27' 00" E
Rick, I would like my Stamp to calculate every think and move, my panels faced
to the sun, my be to move every minute a bit, even if there are only clouds.
I used an shade-seeker before, but on a day where the sun cams out only
sometimes for some minutes, the shade-seeker didn't find the right position and
with a scan the whole thing moved up and down for nothing. Then I added "a small
automatic moving in interval in case the shade-seeker could not see the
sun..but I like the idea to find the "sun's position" by calculation ..and .less
hardware .
Any way I need a stamp to do some other job too:
**to turn the panels back in the night,
** passé reference switch
**to check if there is to much wind, to put the panels in save position and fix
them.
**and some alarm/safety functions.
...
ooh my e-mail gets long..
I am from germany but some panels should be used in Portugal too, so I want to
change only
LATITUDE and LONGITUDE in the program and it should wok.....
regards Heinz
Original Message
From: Dov Yassky
To: basicstamps@yahoogroups.com
Sent: Thursday, March 11, 2004 8:30 AM
Subject: RE: [noparse][[/noparse]basicstamps] Re: sun tracker
Heinz,
Many years ago I wrote a Turbo Pascal (or maybe it was Power Basic)
program that calculates sun azimuth and elevation for any latitude,
longitude, date and time. I don't remember if height above sea level
was considered too. The results were within 1 or 2 degrees compared to
almanac values. I doubt if the program can practically be translated
into pbasic for stamp usage, but if you are interested, I'll try to find
it.
they give help in my project. (playing with solar panels)
I would like to calculate the position of the sun, only
depending, on my position an the earth, and depending, on the date and
time.
I have an RF atomic time receiver (for Germany), 2 stepper motors and a
stamp.
The clock with the stamp und the steppers work fine, but I have problems
with the
calculations of the position of the sun.
Do You know the formula, or a link, or a similar project,
or even an pbasic program?
It would make it easier for me
Regards Heinz
Original Message
From: Richard C. Walter Jr.
To: basicstamps@yahoogroups.com
Sent: Wednesday, March 10, 2004 2:46 AM
Subject: Re: [noparse][[/noparse]basicstamps] Re: sun tracker
I thought I would throw my two cents into the array (sorry for the
pun).
The earth actually turns about 361 degrees per day. It would be
easier to
explain with a diagram but here goes. Since the earth rotates on its
axis
and revolves around the sun, the earth must turn a little more than
360
degrees per day to play "catch up" to the sun. If you think of the
earth
moving in its orbit aorund the sun, it moves around 1 degree per day
(360
degrees in 365 days). Since the earth moved through space about 1
degree,
it must turn on its axis an extra degree (361) to point back to the
sun.
In other words, if you had a sundial on the earth indicating it is
noon, the
earth would turn about 361 degrees to have the sundial say it is noon
again.
This is one reason why we have the equation of time. (The difference
between
clock time and sundial time). The sun runs "fast" and "slow" at
different
times during the year because the of the earth turning (rotating) a
different amount than 360 degrees per day.
Also, at the solstices, the sun appears to move parallel to the
ecliptic
(sun's path on the celestial sphere) so the sun moves a greater
distance
eastward per day. At the equinoxes, the sun's path is more of a right
angle
to the ecliptic (sun is moving above or below the celestial equator)
so it
does not move as far eastward as other times of the year.
Look for "analemma" with google and check out the very good
explainations
regarding this process. The analemma is a figure 8 that show the
equation of
time on the X axis and the declination of the sun (or the latitude of
sun's
rays 90 degrees overhead) for each day of the year on the Y axis. It
used
to be commonly found on old maps and globes in the Pacific Ocean where
there
was nothing but water!
Finally, since we call one day (24 hours) the time it takes from
sunrise to
sunrise it does not matter if it is 360 or 361 degrees. Everyone is
correct
about the sun moving 1 degree every 4 minutes, but you must remember
that is
an average.
If you want to refer to a day as the time it takes the earth to turn
exactly
360 degrees, we are talking about a sidereal day (star time). A
sidereal
clock runs faster than a "sun" clock (like on the wall). A sidereal
day is
approx. 23 hours, 56 minutes, and 4.09 seconds.
If you view a star above a branch of a tree tonight at 9 PM (on your
regular
clock) and go out each night at 9 PM, the star will continually move
away
from the branch. If you went out at 9 hours on your sidereal clock
each
night, the star will be in the exact same position relative to the
tree,
night after night.
By the way, solar clocks (wall clocks) and sidereal clocks agree on
one day,
the autumnal equinox.
Sorry you got me started. I'll crawl back in my hole and lurk another
3 or
4 years.
Rick
To UNSUBSCRIBE, just send mail to: basicstamps-unsubscribe@yahoogroups.com
from the same email address that you subscribed. Text in the Subject
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[noparse][[/noparse]Non-text portions of this message have been removed]
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Yahoo! Groups Links
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[noparse][[/noparse]Non-text portions of this message have been removed]
Hi Heinz. I'll let Dave help you with the program for now. I am rusty with
pbasic and it is much easier for me to calculate things involving angles and
trig using a spreadsheet.
If you ever need some calculations to check to see if your Stamp program is
correct, just ask and I'll send the data or check with the Naval Observatory
site.
To answer your question, I used the formula.....
Altitude of the sun = (90 degress - your latitude) + Declination of the sun
on the day you wish to calculate the noon sun angle.
You can get the declination of the sun for any day of the year from an
analemma. The declination of the sun is the same for all places on earth,
no matter what the latitude or longitude. The declination varies between
+23.45 degrees and -23.45 degrees.
My examples: Since I live at 40 degrees N
Vernal Equinox (Spring) (declination of sun = 0 degrees)
50 = (90-40) + 0
Summer Solstice (declination of sun = +23.5 degrees)
73.5 = (90-40) + 23.5
Autumnal Equinox (Fall) (declination of sun = 0 degrees)
50 = (90-40) + 0
Winter Solstice (declination of sun = -23.5 degrees)
26.5 = (90-40) +(-23.5)
For your location, the noon angle of the sun for each season would be:
Vernal Equinox = 40 degrees = (90-50) + 0
Summer Solstice = 63.5 degrees = (90-50) +23.5
Autumnal Equinox = 40 degrees = (90-50) + 0
Winter Solstice = 16.5 degrees = (90-50) + (-23.5)
If you have the stamp use the above formula, you will get the noon sun angle
but it will not help for all the other clock times of the day. Also, since
the sun runs fast and slow, due to the equation of time, the sun does not
actually reach its peak altitude at noon.
This only occurs 4 times a year. It may vary as much as 16 minutes fast and
14 minutes slow.
On March 12, the sun is 9 minutes and 36 seconds slow. Therefore, it will
reach its peak altitude at 12:09:36 PM at the prime meridian (0 degrees) --
the center of your time zone. Since you live almost 7.5 degrees east of your
time meridian, the sun arrives at your location 30 minutes (4 minutes per
degree) before it arrives at the prime meridian (the center of your time
zone). So, if you use your wall clock (based on time at the prime meridian),
your sundial will say it is noon 1/2 hour before your wall clock says it is
noon.
You then need to combine the equation of time (9 minutes and 36 seconds
slow), with the sun usually being 30 minutes fast at your house, to make the
sun 20 minutes and 24 seconds fast, compared to your clock. So for March
12, 2004, your sundial would say it is noon when your clock says it is only
11:39:36 AM
I have always wanted to make a digital sundial using a microcontroller but
did not find the time to do it! Your project sounds like it would be fun.
Many years ago, when C Band satellie service jsut started, I picked up a couple
of dish antennas from the Stanford Radio Astronomy filed just off of 280
opposite the big dish. They had 32 of these ten foot dishes tracking the Sun
and covering some thousands of feet. It was done using a single centtrally
located motor driving line shafts for right ascention, since the dishes were
mounted on shafts that were polar aligned. There was an adjustment that looked
like the head of a bolt that would adjust the declination for the season of the
year.
There was a thing that looked similar to the rear end from a car with a second
motor that could be used to move the dishes at a rate that was different from
the Earth's rotation and was used for end of the day return and for morning
sync.
If you have a decent clock and calander you could point at the Sun without
seeing it at all, which would be good when there's clouds. It's also good not
to be making any moves that are not necessary since that uses extra electricity.
Note that the COS function is broad at the peak. For example you only have a
10% loss if the panel is misaligned by 25.8 degrees, or 5% at 18.2 degrees, so
tracking to sub degree accuracy is not needed. Since it takes more power to
start moving than to move continously it will take less energy to make fewer
moves, the ideal case is continous movement.
Many years ago, when C Band satellie service jsut started, I picked up a
couple of dish antennas from the Stanford Radio Astronomy filed just off of
280 opposite the big dish. They had 32 of these ten foot dishes tracking
the Sun and covering some thousands of feet. It was done using a single
centtrally located motor driving line shafts for right ascention, since the
dishes were mounted on shafts that were polar aligned. There was an
adjustment that looked like the head of a bolt that would adjust the
declination for the season of the year.
There was a thing that looked similar to the rear end from a car with a
second motor that could be used to move the dishes at a rate that was
different from the Earth's rotation and was used for end of the day return
and for morning sync.
If you have a decent clock and calander you could point at the Sun without
seeing it at all, which would be good when there's clouds. It's also good
not to be making any moves that are not necessary since that uses extra
electricity.
Note that the COS function is broad at the peak. For example you only have
a 10% loss if the panel is misaligned by 25.8 degrees, or 5% at 18.2
degrees, so tracking to sub degree accuracy is not needed. Since it takes
more power to start moving than to move continously it will take less energy
to make fewer moves, the ideal case is continous movement.
To UNSUBSCRIBE, just send mail to: basicstamps-unsubscribe@yahoogroups.com
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Polar rotational alignment is of little use in following the Sun because, as
seen from Earth, the Sun follows the ecliptic, which is not in alignment with
the poles/equator Earth rotational movement, but rather is offset by 23.5
degrees (actually, it's the Earth's rotation that is offset from the plane of
the
solar system, but that's not the way it looks from here on Earth).
Hence, while a Polar rotation mount is good for star-tracking, it is not
useful for following the motions of planets or the Sun.
Also discussing solar tracking, not only does the sun "rise" to a different
maximal height at local noon each day depending on the time of year, the
compass point locations of sunrise and sunset also change daily.
At most any location on earth, the Sun will appear to rise directly from the
East and set directly to the West only on the equinoxes. The only places this
isn't strictly true are the poles (where, on an equinox, the sun will appear
to hug the horizon, rotating around you), but few of us will be setting up
Stamp Solar Trackers there. And it wouldn't work at all there half of the year,
anyway.
;-)
But, back to the basics of solar tracking. As mentioned by others before,
there are two motions going on: the Earth's daily rotation, and the Earth's
yearly revolution about the Sun.
If you made a device that rotated on a Polar-oriented axle once every 24
hours (a 24-hour clock) to synchronously follow the generally East-to-West
movement of the Sun, you would also need another to secondarily swing the angle
of
the axle around (at a 23.5 degree angle off Polar) to adjust for the ecliptic,
using sidereal ("star") time, making the axle describe a cone shape every
"star" day, mirroring the apparent wobble (vis a vis the Sun) of the Earth's
axis.
This one modification to the basic axle motion would then allow you to track
the sun with very good accuracy almost indefinitely, once you got everything
(Polar axle rotation, secondary axle motion, Sun) aligned and sync'ed up.
It may sound complex, but the general idea is not.
Copernicus figured out the gist of it nearly five hundred years ago.
David P. Reaves, III
TransLanTech Sound, LLC
Creators of the Award-Winning "Ariane Stereo Audio Leveler"
In a message dated Thursday, March 11, 2004 8:05 PM Brooke Clarke
[noparse]/noparse]mailto:[url=http://forums.parallaxinc.com/group/basicstamps/post?postID=HWjYZe6bVIfRT7L_EIo-jnX3CcivKpSQizrxk3OvvIhWyrzP4_ViV8--QJn9CcidIv1psqZen90]brooke@p...[/url wrote:
<<
> Hi:
>
> Many years ago, when C Band satellie service jsut started, I picked up a
> couple of dish antennas from the Stanford Radio Astronomy filed just off of
> 280 opposite the big dish.· They had 32 of these ten foot dishes tracking
> the Sun and covering some thousands of feet.· It was done using a single
> centtrally located motor driving line shafts for right ascention, since the
> dishes were mounted on shafts that were polar aligned.· There was an
> adjustment that looked like the head of a bolt that would adjust the
> declination for the season of the year.
>
> There was a thing that looked similar to the rear end from a car with a
> second motor that could be used to move the dishes at a rate that was
> different from the Earth's rotation and was used for end of the day return
> and for morning sync.
>
> If you have a decent clock and calander you could point at the Sun without
> seeing it at all, which would be good when there's clouds.· It's also good
> not to be making any moves that are not necessary since that uses extra
> electricity.
>
> Note that the COS function is broad at the peak.· For example you only have
> a 10% loss if the panel is misaligned by 25.8 degrees, or 5% at 18.2
> degrees, so tracking to sub degree accuracy is not needed.· Since it takes
> more power to start moving than to move continously it will take less energy
> to make fewer moves, the ideal case is continous movement.
>
> Just some ideas,
>
> Brooke Clarke, N6GCE
> http://www.RPC68.com
> >>
[noparse][[/noparse]Non-text portions of this message have been removed]
There is also a link to a pdf that has a lot more detail. Basically,
it is a pinhole camera about the size of Lincoln's head on a penny.
The position of the sun's image as it moves across the 2-D CMOS
sensor array during the course of a few hours is determined and
number crunching determines the earth's rotation axis. It looks like
the interface to the chip is SPI, so the Stamp could read it (no,
they don't have them for sale at any price--this is taxpayer money).
Here the downloads are only possible from the U.S.A
????????????????????????????????????????????
"NTB TSP Download Services
Problem:
Sorry, this service is available only in the U.S.A. or in U.S. territories. You
appear to be attempting access from elsewhere or via an internet service
provider who is based elsewhere. "
????????????????????????????????????????????
regards Heinz Germany
Original Message
From: Tracy Allen
To: basicstamps@yahoogroups.com
Sent: Saturday, March 13, 2004 5:56 AM
Subject: [noparse][[/noparse]basicstamps] Re: Re: sun tracker
Here is a link to an interesting sundial-on-a-chip from Jet Propulsion Labs:
There is also a link to a pdf that has a lot more detail. Basically,
it is a pinhole camera about the size of Lincoln's head on a penny.
The position of the sun's image as it moves across the 2-D CMOS
sensor array during the course of a few hours is determined and
number crunching determines the earth's rotation axis. It looks like
the interface to the chip is SPI, so the Stamp could read it (no,
they don't have them for sale at any price--this is taxpayer money).
To UNSUBSCRIBE, just send mail to: basicstamps-unsubscribe@yahoogroups.com
from the same email address that you subscribed. Text in the Subject and Body
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[noparse][[/noparse]Non-text portions of this message have been removed]
--- In basicstamps@yahoogroups.com, "HSchwenk_Web.de" <HSchwenk@w...>
wrote:
> Hi
>
> Here the downloads are only possible from the U.S.A
>
> regards Heinz Germany
>
but, pdf files of the page are available !
check the files section of the basicstamps site under Digial Sundial.
Funny, but I did find the SunAngle program. It was written 15 years ago
in Turbo Pascal 6.0 and, as usual with Pascal, it is small: 9K source,
13K compiled.
Latitude and longitude are considered to be constants, appropriate to my
part of the world, but can easily be converted to changing inputs or
prompted inputs.
As written, the program outputs a table for an arbitrary date, a
starting time, an ending time and a time-step, but this too can be
easily changed.
Mathematically it is simple and uses an approximation for the
time-equation which proved good enough. You can probably translate the
whole thing quite easily because Pascal is reasonably self-documenting.
The compiled program (done 15 years ago) still works in a DOS window of
a WINXP machine.
Let me know if you want it and I'll send it to you (and whoever is
interested) off-list.
Hi Dave, Rick, Dov, Jack and.....
thanks for Your quick answers
Dave
Your program is exactly what I am looking for. I don't understand Turbo
Pascal, but know somebody who may help me. Also, If You have the
calculation in usual math, I may have the chance to make my stamp to do
the job......
I would like that my stamp calculate first the azimuth and elevation
and then calculate the steps for my two step motors to move to.
In my program I like to use the time and date the latitude and
longitude.
As I don't need high angel resolution I can ignore the height above sea
level and may be simplify the calculation too.
Rick
How did You calculate This?: "peak of 50 degrees above my horizon. On
the first day of
winter it is a pitifull 26.5 degrees and the first day of summer it is
at 73.5 degrees"
...................................................................
The U.S. Naval Observatory site is interesting and the link there to
the Geonam Query page too.
My LATITUDE is 50° 04' 00" N
My LONGITUDE is 007° 27' 00" E
Rick, I would like my Stamp to calculate every think and move, my panels
faced to the sun, my be to move every minute a bit, even if there are
only clouds.
I used an shade-seeker before, but on a day where the sun cams out only
sometimes for some minutes, the shade-seeker didn't find the right
position and with a scan the whole thing moved up and down for nothing.
Then I added "a small automatic moving in interval in case the
shade-seeker could not see the sun..but I like the idea to find the
"sun's position" by calculation ..and .less hardware .
Any way I need a stamp to do some other job too:
**to turn the panels back in the night,
** passé reference switch
**to check if there is to much wind, to put the panels in save position
and fix them.
**and some alarm/safety functions.
...
ooh my e-mail gets long..
I am from germany but some panels should be used in Portugal too, so I
want to change only
LATITUDE and LONGITUDE in the program and it should wok.....
regards Heinz
Original Message
From: Dov Yassky
To: basicstamps@yahoogroups.com
Sent: Thursday, March 11, 2004 8:30 AM
Subject: RE: [noparse][[/noparse]basicstamps] Re: sun tracker
Heinz,
Many years ago I wrote a Turbo Pascal (or maybe it was Power Basic)
program that calculates sun azimuth and elevation for any latitude,
longitude, date and time. I don't remember if height above sea level
was considered too. The results were within 1 or 2 degrees compared
to
almanac values. I doubt if the program can practically be translated
into pbasic for stamp usage, but if you are interested, I'll try to
find
it.
they give help in my project. (playing with solar panels)
I would like to calculate the position of the sun, only
depending, on my position an the earth, and depending, on the date and
time.
I have an RF atomic time receiver (for Germany), 2 stepper motors and
a
stamp.
The clock with the stamp und the steppers work fine, but I have
problems
with the
calculations of the position of the sun.
Do You know the formula, or a link, or a similar project,
or even an pbasic program?
It would make it easier for me
Regards Heinz
Original Message
From: Richard C. Walter Jr.
To: basicstamps@yahoogroups.com
Sent: Wednesday, March 10, 2004 2:46 AM
Subject: Re: [noparse][[/noparse]basicstamps] Re: sun tracker
I thought I would throw my two cents into the array (sorry for the
pun).
The earth actually turns about 361 degrees per day. It would be
easier to
explain with a diagram but here goes. Since the earth rotates on its
axis
and revolves around the sun, the earth must turn a little more than
360
degrees per day to play "catch up" to the sun. If you think of the
earth
moving in its orbit aorund the sun, it moves around 1 degree per day
(360
degrees in 365 days). Since the earth moved through space about 1
degree,
it must turn on its axis an extra degree (361) to point back to the
sun.
In other words, if you had a sundial on the earth indicating it is
noon, the
earth would turn about 361 degrees to have the sundial say it is
noon
again.
This is one reason why we have the equation of time. (The difference
between
clock time and sundial time). The sun runs "fast" and "slow" at
different
times during the year because the of the earth turning (rotating) a
different amount than 360 degrees per day.
Also, at the solstices, the sun appears to move parallel to the
ecliptic
(sun's path on the celestial sphere) so the sun moves a greater
distance
eastward per day. At the equinoxes, the sun's path is more of a
right
angle
to the ecliptic (sun is moving above or below the celestial equator)
so it
does not move as far eastward as other times of the year.
Look for "analemma" with google and check out the very good
explainations
regarding this process. The analemma is a figure 8 that show the
equation of
time on the X axis and the declination of the sun (or the latitude
of
sun's
rays 90 degrees overhead) for each day of the year on the Y axis.
It
used
to be commonly found on old maps and globes in the Pacific Ocean
where
there
was nothing but water!
Finally, since we call one day (24 hours) the time it takes from
sunrise to
sunrise it does not matter if it is 360 or 361 degrees. Everyone is
correct
about the sun moving 1 degree every 4 minutes, but you must remember
that is
an average.
If you want to refer to a day as the time it takes the earth to turn
exactly
360 degrees, we are talking about a sidereal day (star time). A
sidereal
clock runs faster than a "sun" clock (like on the wall). A sidereal
day is
approx. 23 hours, 56 minutes, and 4.09 seconds.
If you view a star above a branch of a tree tonight at 9 PM (on your
regular
clock) and go out each night at 9 PM, the star will continually move
away
from the branch. If you went out at 9 hours on your sidereal clock
each
night, the star will be in the exact same position relative to the
tree,
night after night.
By the way, solar clocks (wall clocks) and sidereal clocks agree on
one day,
the autumnal equinox.
Sorry you got me started. I'll crawl back in my hole and lurk
another
3 or
4 years.
Rick
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Funny, but I did find the SunAngle program. It was written 15 years ago
in Turbo Pascal 6.0 and, as usual with Pascal, it is small: 9K source,
13K compiled.
Latitude and longitude are considered to be constants, appropriate to my
part of the world, but can easily be converted to changing inputs or
prompted inputs.
As written, the program outputs a table for an arbitrary date, a
starting time, an ending time and a time-step, but this too can be
easily changed.
Mathematically it is simple and uses an approximation for the
time-equation which proved good enough. You can probably translate the
whole thing quite easily because Pascal is reasonably self-documenting.
The compiled program (done 15 years ago) still works in a DOS window of
a WINXP machine.
Let me know if you want it and I'll send it to you (and whoever is
interested) off-list.
Hi Dave, Rick, Dov, Jack and.....
thanks for Your quick answers
Dave
Your program is exactly what I am looking for. I don't understand Turbo
Pascal, but know somebody who may help me. Also, If You have the
calculation in usual math, I may have the chance to make my stamp to do
the job......
I would like that my stamp calculate first the azimuth and elevation
and then calculate the steps for my two step motors to move to.
In my program I like to use the time and date the latitude and
longitude.
As I don't need high angel resolution I can ignore the height above sea
level and may be simplify the calculation too.
Rick
How did You calculate This?: "peak of 50 degrees above my horizon. On
the first day of
winter it is a pitifull 26.5 degrees and the first day of summer it is
at 73.5 degrees"
...................................................................
The U.S. Naval Observatory site is interesting and the link there to
the Geonam Query page too.
My LATITUDE is 50° 04' 00" N
My LONGITUDE is 007° 27' 00" E
Rick, I would like my Stamp to calculate every think and move, my panels
faced to the sun, my be to move every minute a bit, even if there are
only clouds.
I used an shade-seeker before, but on a day where the sun cams out only
sometimes for some minutes, the shade-seeker didn't find the right
position and with a scan the whole thing moved up and down for nothing.
Then I added "a small automatic moving in interval in case the
shade-seeker could not see the sun..but I like the idea to find the
"sun's position" by calculation ..and .less hardware .
Any way I need a stamp to do some other job too:
**to turn the panels back in the night,
** passé reference switch
**to check if there is to much wind, to put the panels in save position
and fix them.
**and some alarm/safety functions.
...
ooh my e-mail gets long..
I am from germany but some panels should be used in Portugal too, so I
want to change only
LATITUDE and LONGITUDE in the program and it should wok.....
regards Heinz
Original Message
From: Dov Yassky
To: basicstamps@yahoogroups.com
Sent: Thursday, March 11, 2004 8:30 AM
Subject: RE: [noparse][[/noparse]basicstamps] Re: sun tracker
Heinz,
Many years ago I wrote a Turbo Pascal (or maybe it was Power Basic)
program that calculates sun azimuth and elevation for any latitude,
longitude, date and time. I don't remember if height above sea level
was considered too. The results were within 1 or 2 degrees compared
to
almanac values. I doubt if the program can practically be translated
into pbasic for stamp usage, but if you are interested, I'll try to
find
it.
they give help in my project. (playing with solar panels)
I would like to calculate the position of the sun, only
depending, on my position an the earth, and depending, on the date and
time.
I have an RF atomic time receiver (for Germany), 2 stepper motors and
a
stamp.
The clock with the stamp und the steppers work fine, but I have
problems
with the
calculations of the position of the sun.
Do You know the formula, or a link, or a similar project,
or even an pbasic program?
It would make it easier for me
Regards Heinz
Original Message
From: Richard C. Walter Jr.
To: basicstamps@yahoogroups.com
Sent: Wednesday, March 10, 2004 2:46 AM
Subject: Re: [noparse][[/noparse]basicstamps] Re: sun tracker
I thought I would throw my two cents into the array (sorry for the
pun).
The earth actually turns about 361 degrees per day. It would be
easier to
explain with a diagram but here goes. Since the earth rotates on its
axis
and revolves around the sun, the earth must turn a little more than
360
degrees per day to play "catch up" to the sun. If you think of the
earth
moving in its orbit aorund the sun, it moves around 1 degree per day
(360
degrees in 365 days). Since the earth moved through space about 1
degree,
it must turn on its axis an extra degree (361) to point back to the
sun.
In other words, if you had a sundial on the earth indicating it is
noon, the
earth would turn about 361 degrees to have the sundial say it is
noon
again.
This is one reason why we have the equation of time. (The difference
between
clock time and sundial time). The sun runs "fast" and "slow" at
different
times during the year because the of the earth turning (rotating) a
different amount than 360 degrees per day.
Also, at the solstices, the sun appears to move parallel to the
ecliptic
(sun's path on the celestial sphere) so the sun moves a greater
distance
eastward per day. At the equinoxes, the sun's path is more of a
right
angle
to the ecliptic (sun is moving above or below the celestial equator)
so it
does not move as far eastward as other times of the year.
Look for "analemma" with google and check out the very good
explainations
regarding this process. The analemma is a figure 8 that show the
equation of
time on the X axis and the declination of the sun (or the latitude
of
sun's
rays 90 degrees overhead) for each day of the year on the Y axis.
It
used
to be commonly found on old maps and globes in the Pacific Ocean
where
there
was nothing but water!
Finally, since we call one day (24 hours) the time it takes from
sunrise to
sunrise it does not matter if it is 360 or 361 degrees. Everyone is
correct
about the sun moving 1 degree every 4 minutes, but you must remember
that is
an average.
If you want to refer to a day as the time it takes the earth to turn
exactly
360 degrees, we are talking about a sidereal day (star time). A
sidereal
clock runs faster than a "sun" clock (like on the wall). A sidereal
day is
approx. 23 hours, 56 minutes, and 4.09 seconds.
If you view a star above a branch of a tree tonight at 9 PM (on your
regular
clock) and go out each night at 9 PM, the star will continually move
away
from the branch. If you went out at 9 hours on your sidereal clock
each
night, the star will be in the exact same position relative to the
tree,
night after night.
By the way, solar clocks (wall clocks) and sidereal clocks agree on
one day,
the autumnal equinox.
Sorry you got me started. I'll crawl back in my hole and lurk
another
3 or
4 years.
Rick
To UNSUBSCRIBE, just send mail to: basicstamps-unsubscribe@yahoogroups.com
from the same email address that you subscribed. Text in the
Subject
and Body of the message will be ignored.
Yahoo! Groups Links
[noparse][[/noparse]Non-text portions of this message have been removed]
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[noparse][[/noparse]Non-text portions of this message have been removed]
The Sun is, of course, always on the ecliptic. :-)
But it appears that where the sun is at any given time will not be where the
ecliptic was/will be a few hours before or after, since the ecliptic also
appears to shift throughout the day.
The ecliptic can be imagined as like a big hula hoop, that appears to swing
up and down and around roughly once a day. It's hard to tell it's shifting,
because there aren't that many celestial bodies riding the ecliptic to show its
motion obviously.
The ecliptic (the average plane of the orbits of the Earth, moon and the
planets about the Sun] only *appears* to vary when viewed from Earth, due to the
23.5 degree offset of Earth's rotation from the ecliptic.
The ecliptic for a given location's Earth latitude is "locked in," and quite
predictable. Its maximum apparent height in degrees above horizon (always seen
directly due South, in the Northern Hemisphere) never changes, though the
time of day of maximum does, depending upon the day of the year.
This maximum angle above horizon can be simply computed: it is equal to (90
minus the degrees in latitude of the location) + 23.5.
For example, if you live in New York City, the latitude there is 41N.
Subtracting 41 from 90, equals 49; add 23.5 to 49, and you know that the
ecliptic
reaches a maximum of 72.5 degrees above horizon in the southern sky over NYC.
The time of day that this maximum occurs changes through the year. On the
summer solstice the maximum 'height' due South is at local noon. This makes
sense; everyone knows, the sun gets highest on the longest day of the year,
about
the 21st of June (for the Northern Hemisphere; December 21 in the Southern
Hemisphere).
On the winter solstice, the maximum height of the ecliptic (still due South,
it's ALWAYS due South) is at midnight. On the Vernal (spring) equinox, the
maximum due south is at 6AM, and on the Autumnal equinox, it's at 6:00PM.
For this reason, the brightest, highest full moon is the one that's closest
to December 21 every year. But the highest *half* moon will be on one of the
equinoxes, depending on whether the moon is waxing or waning.
Hey, a MOON tracker... now THERE's a PROJECT!!!
David P. Reaves, III
TransLanTech Sound, LLC
Creators of the Award-Winning "Ariane Stereo Audio Leveler"
In a message dated Wednesday, March 10, 2004 2:46 AM, Richard C. Walter Jr.
writes:
> <<
> ·· I thought I would throw my two cents into the array (sorry for the pun).
>
> ·· The earth actually turns about 361 degrees per day.· It would be easier
> to
> ·· explain with a diagram but here goes. Since the earth rotates on its
> axis
> ·· and revolves around the sun, the earth must turn a little more than 360
> ·· degrees per day to play "catch up" to the sun.· If you think of the
> earth
> ·· moving in its orbit aorund the sun, it moves around 1 degree per day
> · (360 degrees in 365 days).· Since the earth moved through space about
> 1
> · degree, it must turn on its axis an extra degree (361) to point back
> to the
> · sun.
>
> ·· In other words, if you had a sundial on the earth indicating it is noon,
> the
> ·· earth would turn about 361 degrees to have the sundial say it is noon
> again.
> ·· This is one reason why we have the equation of time. (The difference
> between
> ·· clock time and sundial time).· The sun runs "fast" and "slow" at
> different
> ·· times during the year because the of the earth turning (rotating) a
> ·· different amount than 360 degrees per day.
>
> ·· Also, at the solstices, the sun appears to move parallel to the ecliptic
> ·· (sun's path on the celestial sphere) so the sun moves a greater distance
> ·· eastward per day.· At the equinoxes, the sun's path is more of a right
> angle
> ·· to the ecliptic (sun is moving above or below the celestial equator) so
> it
> ·· does not move as far eastward as other times of the year.
> >>
[noparse][[/noparse]Non-text portions of this message have been removed]
Comments
> I would like to calculate the position of the sun, only
> depending, on my position an the earth, and depending, on the date and time.
For actual code, "Astronomical Algorithms", Jan Meeus.
Mr. Meeus is Belgian - It would surprise me if there
is not a German edition. The book is a classic.
Jack
location at the following site:
http://aa.usno.navy.mil/
This is the U.S. Naval Observatory site. They have great software to allow
you to calculate many things. This place will allow you to choose the time
interval for the position of the sun for any place on earth for one day. it
will give the altitude and azimuith of the sun for your location.
If you have access to an analemma you can use this formula to calculate the
sun's noon altitude. Sun altitude = ((90 degrees - your latitude) +
declination of the sun on a specific date The analemma will give you the
declination of the sun on every day of the year. You should be able to get
it on the net, or I can give you the info.
For the upcoming vernal equinox, the sun's declination will be 0 degrees
(sun rays directly on the equator). At my latitude 40 degrees N, the sun
will reach a peak of 50 degrees above my horizon. On the first day of
winter it is a pitifull 26.5 degrees and the first day of summer it is at
73.5 degrees!
If you need more info, give me your latitude and longitude, the time
interval you would like, and the days you wish and I will run software I
have to calculate the sun's altitude and azimuth for your location. I
should be able to give it to you as plain ASCII text, a Microsoft Word
document, or in a Microsoft Excel spreadsheet. Let me know if you would
like me to run the info, and what format would be best for you. I can send
it to your e-mail address as an attachement.
Rick
Original Message
From: "HSchwenk_Web.de" <HSchwenk@w...>
To: <basicstamps@yahoogroups.com>
Sent: Wednesday, December 10, 2003 3:12 PM
Subject: Re: [noparse][[/noparse]basicstamps] Re: sun tracker
> Hi Rick and group
>
>
>
> Your "two cents" are interesting!
>
> they give help in my project. (playing with solar panels)
>
>
>
> I would like to calculate the position of the sun, only
>
> depending, on my position an the earth, and depending, on the date and
time.
>
> I have an RF atomic time receiver (for Germany), 2 stepper motors and a
stamp.
>
> The clock with the stamp und the steppers work fine, but I have problems
with the
>
> calculations of the position of the sun.
>
> Do You know the formula, or a link, or a similar project,
>
> or even an pbasic program?
>
>
>
> It would make it easier for me
>
>
>
> Regards Heinz
>
>
>
>
>
>
>
>
>
Original Message
>
> From: Richard C. Walter Jr.
> To: basicstamps@yahoogroups.com
> Sent: Wednesday, March 10, 2004 2:46 AM
> Subject: Re: [noparse][[/noparse]basicstamps] Re: sun tracker
>
>
> I thought I would throw my two cents into the array (sorry for the pun).
>
> The earth actually turns about 361 degrees per day. It would be easier
to
> explain with a diagram but here goes. Since the earth rotates on its
axis
> and revolves around the sun, the earth must turn a little more than 360
> degrees per day to play "catch up" to the sun. If you think of the
earth
> moving in its orbit aorund the sun, it moves around 1 degree per day
(360
> degrees in 365 days). Since the earth moved through space about 1
degree,
> it must turn on its axis an extra degree (361) to point back to the sun.
>
> In other words, if you had a sundial on the earth indicating it is noon,
the
> earth would turn about 361 degrees to have the sundial say it is noon
again.
> This is one reason why we have the equation of time. (The difference
between
> clock time and sundial time). The sun runs "fast" and "slow" at
different
> times during the year because the of the earth turning (rotating) a
> different amount than 360 degrees per day.
>
> Also, at the solstices, the sun appears to move parallel to the ecliptic
> (sun's path on the celestial sphere) so the sun moves a greater distance
> eastward per day. At the equinoxes, the sun's path is more of a right
angle
> to the ecliptic (sun is moving above or below the celestial equator) so
it
> does not move as far eastward as other times of the year.
>
> Look for "analemma" with google and check out the very good
explainations
> regarding this process. The analemma is a figure 8 that show the
equation of
> time on the X axis and the declination of the sun (or the latitude of
sun's
> rays 90 degrees overhead) for each day of the year on the Y axis. It
used
> to be commonly found on old maps and globes in the Pacific Ocean where
there
> was nothing but water!
>
> Finally, since we call one day (24 hours) the time it takes from sunrise
to
> sunrise it does not matter if it is 360 or 361 degrees. Everyone is
correct
> about the sun moving 1 degree every 4 minutes, but you must remember
that is
> an average.
>
> If you want to refer to a day as the time it takes the earth to turn
exactly
> 360 degrees, we are talking about a sidereal day (star time). A
sidereal
> clock runs faster than a "sun" clock (like on the wall). A sidereal day
is
> approx. 23 hours, 56 minutes, and 4.09 seconds.
>
> If you view a star above a branch of a tree tonight at 9 PM (on your
regular
> clock) and go out each night at 9 PM, the star will continually move
away
> from the branch. If you went out at 9 hours on your sidereal clock each
> night, the star will be in the exact same position relative to the tree,
> night after night.
>
> By the way, solar clocks (wall clocks) and sidereal clocks agree on one
day,
> the autumnal equinox.
>
> Sorry you got me started. I'll crawl back in my hole and lurk another 3
or
> 4 years.
>
> Rick
>
>
>
>
> To UNSUBSCRIBE, just send mail to:
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Many years ago I wrote a Turbo Pascal (or maybe it was Power Basic)
program that calculates sun azimuth and elevation for any latitude,
longitude, date and time. I don't remember if height above sea level
was considered too. The results were within 1 or 2 degrees compared to
almanac values. I doubt if the program can practically be translated
into pbasic for stamp usage, but if you are interested, I'll try to find
it.
Dov
Original Message
From: HSchwenk@w... [noparse]/noparse]mailto:[url=http://forums.parallaxinc.com/group/basicstamps/post?postID=E3jdsqAhrerH6siyKT24Q4ILgz6FK0ZxWWZIJvmpefZylhqQkotd-mkj4Q0u346RS5nypTkAaryciQ]HSchwenk@w...[/url
Sent: Wednesday, 10 December 2003 10:12 PM
To: basicstamps@yahoogroups.com
Subject: Re: [noparse][[/noparse]basicstamps] Re: sun tracker
Hi Rick and group
Your "two cents" are interesting!
they give help in my project. (playing with solar panels)
I would like to calculate the position of the sun, only
depending, on my position an the earth, and depending, on the date and
time.
I have an RF atomic time receiver (for Germany), 2 stepper motors and a
stamp.
The clock with the stamp und the steppers work fine, but I have problems
with the
calculations of the position of the sun.
Do You know the formula, or a link, or a similar project,
or even an pbasic program?
It would make it easier for me
Regards Heinz
Original Message
From: Richard C. Walter Jr.
To: basicstamps@yahoogroups.com
Sent: Wednesday, March 10, 2004 2:46 AM
Subject: Re: [noparse][[/noparse]basicstamps] Re: sun tracker
I thought I would throw my two cents into the array (sorry for the
pun).
The earth actually turns about 361 degrees per day. It would be
easier to
explain with a diagram but here goes. Since the earth rotates on its
axis
and revolves around the sun, the earth must turn a little more than
360
degrees per day to play "catch up" to the sun. If you think of the
earth
moving in its orbit aorund the sun, it moves around 1 degree per day
(360
degrees in 365 days). Since the earth moved through space about 1
degree,
it must turn on its axis an extra degree (361) to point back to the
sun.
In other words, if you had a sundial on the earth indicating it is
noon, the
earth would turn about 361 degrees to have the sundial say it is noon
again.
This is one reason why we have the equation of time. (The difference
between
clock time and sundial time). The sun runs "fast" and "slow" at
different
times during the year because the of the earth turning (rotating) a
different amount than 360 degrees per day.
Also, at the solstices, the sun appears to move parallel to the
ecliptic
(sun's path on the celestial sphere) so the sun moves a greater
distance
eastward per day. At the equinoxes, the sun's path is more of a right
angle
to the ecliptic (sun is moving above or below the celestial equator)
so it
does not move as far eastward as other times of the year.
Look for "analemma" with google and check out the very good
explainations
regarding this process. The analemma is a figure 8 that show the
equation of
time on the X axis and the declination of the sun (or the latitude of
sun's
rays 90 degrees overhead) for each day of the year on the Y axis. It
used
to be commonly found on old maps and globes in the Pacific Ocean where
there
was nothing but water!
Finally, since we call one day (24 hours) the time it takes from
sunrise to
sunrise it does not matter if it is 360 or 361 degrees. Everyone is
correct
about the sun moving 1 degree every 4 minutes, but you must remember
that is
an average.
If you want to refer to a day as the time it takes the earth to turn
exactly
360 degrees, we are talking about a sidereal day (star time). A
sidereal
clock runs faster than a "sun" clock (like on the wall). A sidereal
day is
approx. 23 hours, 56 minutes, and 4.09 seconds.
If you view a star above a branch of a tree tonight at 9 PM (on your
regular
clock) and go out each night at 9 PM, the star will continually move
away
from the branch. If you went out at 9 hours on your sidereal clock
each
night, the star will be in the exact same position relative to the
tree,
night after night.
By the way, solar clocks (wall clocks) and sidereal clocks agree on
one day,
the autumnal equinox.
Sorry you got me started. I'll crawl back in my hole and lurk another
3 or
4 years.
Rick
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[noparse][[/noparse]Non-text portions of this message have been removed]
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thanks for Your quick answers
Dave
Your program is exactly what I am looking for. I don't understand Turbo Pascal,
but know somebody who may help me. Also, If You have the calculation in usual
math, I may have the chance to make my stamp to do the job......
I would like that my stamp calculate first the azimuth and elevation and then
calculate the steps for my two step motors to move to.
In my program I like to use the time and date the latitude and longitude.
As I don't need high angel resolution I can ignore the height above sea level
and may be simplify the calculation too.
Rick
How did You calculate This?: "peak of 50 degrees above my horizon. On the first
day of
winter it is a pitifull 26.5 degrees and the first day of summer it is at 73.5
degrees"
...................................................................
The U.S. Naval Observatory site is interesting and the link there to the Geonam
Query page too.
My LATITUDE is 50° 04' 00" N
My LONGITUDE is 007° 27' 00" E
Rick, I would like my Stamp to calculate every think and move, my panels faced
to the sun, my be to move every minute a bit, even if there are only clouds.
I used an shade-seeker before, but on a day where the sun cams out only
sometimes for some minutes, the shade-seeker didn't find the right position and
with a scan the whole thing moved up and down for nothing. Then I added "a small
automatic moving in interval in case the shade-seeker could not see the
sun..but I like the idea to find the "sun's position" by calculation ..and .less
hardware .
Any way I need a stamp to do some other job too:
**to turn the panels back in the night,
** passé reference switch
**to check if there is to much wind, to put the panels in save position and fix
them.
**and some alarm/safety functions.
...
ooh my e-mail gets long..
I am from germany but some panels should be used in Portugal too, so I want to
change only
LATITUDE and LONGITUDE in the program and it should wok.....
regards Heinz
Original Message
From: Dov Yassky
To: basicstamps@yahoogroups.com
Sent: Thursday, March 11, 2004 8:30 AM
Subject: RE: [noparse][[/noparse]basicstamps] Re: sun tracker
Heinz,
Many years ago I wrote a Turbo Pascal (or maybe it was Power Basic)
program that calculates sun azimuth and elevation for any latitude,
longitude, date and time. I don't remember if height above sea level
was considered too. The results were within 1 or 2 degrees compared to
almanac values. I doubt if the program can practically be translated
into pbasic for stamp usage, but if you are interested, I'll try to find
it.
Dov
Original Message
From: HSchwenk@w... [noparse]/noparse]mailto:[url=http://forums.parallaxinc.com/group/basicstamps/post?postID=wx7kmtNK4s0a48HdBfczStPmqI7NaBCLw98RGoZn9ZYGtobxPzrt05f2amv31USVt-CcXbLJ]HSchwenk@w...[/url
Sent: Wednesday, 10 December 2003 10:12 PM
To: basicstamps@yahoogroups.com
Subject: Re: [noparse][[/noparse]basicstamps] Re: sun tracker
Hi Rick and group
Your "two cents" are interesting!
they give help in my project. (playing with solar panels)
I would like to calculate the position of the sun, only
depending, on my position an the earth, and depending, on the date and
time.
I have an RF atomic time receiver (for Germany), 2 stepper motors and a
stamp.
The clock with the stamp und the steppers work fine, but I have problems
with the
calculations of the position of the sun.
Do You know the formula, or a link, or a similar project,
or even an pbasic program?
It would make it easier for me
Regards Heinz
Original Message
From: Richard C. Walter Jr.
To: basicstamps@yahoogroups.com
Sent: Wednesday, March 10, 2004 2:46 AM
Subject: Re: [noparse][[/noparse]basicstamps] Re: sun tracker
I thought I would throw my two cents into the array (sorry for the
pun).
The earth actually turns about 361 degrees per day. It would be
easier to
explain with a diagram but here goes. Since the earth rotates on its
axis
and revolves around the sun, the earth must turn a little more than
360
degrees per day to play "catch up" to the sun. If you think of the
earth
moving in its orbit aorund the sun, it moves around 1 degree per day
(360
degrees in 365 days). Since the earth moved through space about 1
degree,
it must turn on its axis an extra degree (361) to point back to the
sun.
In other words, if you had a sundial on the earth indicating it is
noon, the
earth would turn about 361 degrees to have the sundial say it is noon
again.
This is one reason why we have the equation of time. (The difference
between
clock time and sundial time). The sun runs "fast" and "slow" at
different
times during the year because the of the earth turning (rotating) a
different amount than 360 degrees per day.
Also, at the solstices, the sun appears to move parallel to the
ecliptic
(sun's path on the celestial sphere) so the sun moves a greater
distance
eastward per day. At the equinoxes, the sun's path is more of a right
angle
to the ecliptic (sun is moving above or below the celestial equator)
so it
does not move as far eastward as other times of the year.
Look for "analemma" with google and check out the very good
explainations
regarding this process. The analemma is a figure 8 that show the
equation of
time on the X axis and the declination of the sun (or the latitude of
sun's
rays 90 degrees overhead) for each day of the year on the Y axis. It
used
to be commonly found on old maps and globes in the Pacific Ocean where
there
was nothing but water!
Finally, since we call one day (24 hours) the time it takes from
sunrise to
sunrise it does not matter if it is 360 or 361 degrees. Everyone is
correct
about the sun moving 1 degree every 4 minutes, but you must remember
that is
an average.
If you want to refer to a day as the time it takes the earth to turn
exactly
360 degrees, we are talking about a sidereal day (star time). A
sidereal
clock runs faster than a "sun" clock (like on the wall). A sidereal
day is
approx. 23 hours, 56 minutes, and 4.09 seconds.
If you view a star above a branch of a tree tonight at 9 PM (on your
regular
clock) and go out each night at 9 PM, the star will continually move
away
from the branch. If you went out at 9 hours on your sidereal clock
each
night, the star will be in the exact same position relative to the
tree,
night after night.
By the way, solar clocks (wall clocks) and sidereal clocks agree on
one day,
the autumnal equinox.
Sorry you got me started. I'll crawl back in my hole and lurk another
3 or
4 years.
Rick
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basicstamps-unsubscribe@yahoogroups.com
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[noparse][[/noparse]Non-text portions of this message have been removed]
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[noparse][[/noparse]Non-text portions of this message have been removed]
pbasic and it is much easier for me to calculate things involving angles and
trig using a spreadsheet.
If you ever need some calculations to check to see if your Stamp program is
correct, just ask and I'll send the data or check with the Naval Observatory
site.
To answer your question, I used the formula.....
Altitude of the sun = (90 degress - your latitude) + Declination of the sun
on the day you wish to calculate the noon sun angle.
You can get the declination of the sun for any day of the year from an
analemma. The declination of the sun is the same for all places on earth,
no matter what the latitude or longitude. The declination varies between
+23.45 degrees and -23.45 degrees.
My examples: Since I live at 40 degrees N
Vernal Equinox (Spring) (declination of sun = 0 degrees)
50 = (90-40) + 0
Summer Solstice (declination of sun = +23.5 degrees)
73.5 = (90-40) + 23.5
Autumnal Equinox (Fall) (declination of sun = 0 degrees)
50 = (90-40) + 0
Winter Solstice (declination of sun = -23.5 degrees)
26.5 = (90-40) +(-23.5)
For your location, the noon angle of the sun for each season would be:
Vernal Equinox = 40 degrees = (90-50) + 0
Summer Solstice = 63.5 degrees = (90-50) +23.5
Autumnal Equinox = 40 degrees = (90-50) + 0
Winter Solstice = 16.5 degrees = (90-50) + (-23.5)
If you have the stamp use the above formula, you will get the noon sun angle
but it will not help for all the other clock times of the day. Also, since
the sun runs fast and slow, due to the equation of time, the sun does not
actually reach its peak altitude at noon.
This only occurs 4 times a year. It may vary as much as 16 minutes fast and
14 minutes slow.
On March 12, the sun is 9 minutes and 36 seconds slow. Therefore, it will
reach its peak altitude at 12:09:36 PM at the prime meridian (0 degrees) --
the center of your time zone. Since you live almost 7.5 degrees east of your
time meridian, the sun arrives at your location 30 minutes (4 minutes per
degree) before it arrives at the prime meridian (the center of your time
zone). So, if you use your wall clock (based on time at the prime meridian),
your sundial will say it is noon 1/2 hour before your wall clock says it is
noon.
You then need to combine the equation of time (9 minutes and 36 seconds
slow), with the sun usually being 30 minutes fast at your house, to make the
sun 20 minutes and 24 seconds fast, compared to your clock. So for March
12, 2004, your sundial would say it is noon when your clock says it is only
11:39:36 AM
I have always wanted to make a digital sundial using a microcontroller but
did not find the time to do it! Your project sounds like it would be fun.
Rick
Many years ago, when C Band satellie service jsut started, I picked up a couple
of dish antennas from the Stanford Radio Astronomy filed just off of 280
opposite the big dish. They had 32 of these ten foot dishes tracking the Sun
and covering some thousands of feet. It was done using a single centtrally
located motor driving line shafts for right ascention, since the dishes were
mounted on shafts that were polar aligned. There was an adjustment that looked
like the head of a bolt that would adjust the declination for the season of the
year.
There was a thing that looked similar to the rear end from a car with a second
motor that could be used to move the dishes at a rate that was different from
the Earth's rotation and was used for end of the day return and for morning
sync.
If you have a decent clock and calander you could point at the Sun without
seeing it at all, which would be good when there's clouds. It's also good not
to be making any moves that are not necessary since that uses extra electricity.
Note that the COS function is broad at the peak. For example you only have a
10% loss if the panel is misaligned by 25.8 degrees, or 5% at 18.2 degrees, so
tracking to sub degree accuracy is not needed. Since it takes more power to
start moving than to move continously it will take less energy to make fewer
moves, the ideal case is continous movement.
Just some ideas,
Brooke Clarke, N6GCE
http://www.RPC68.com
often. Good source of used parts.
Original Message
From: Brooke Clarke [noparse]/noparse]mailto:[url=http://forums.parallaxinc.com/group/basicstamps/post?postID=ZTthSpH8dEA0wr3Jn01dtVdk6bZIGSnH_ES8_n1wxucOtxKIzt0ER5FKkHEVQnXO5TWhP5ZpNQK_q0o]brooke@p...[/url
Sent: Thursday, March 11, 2004 8:05 PM
To: basicstamps@yahoogroups.com
Subject: [noparse][[/noparse]basicstamps] Re: sun tracker
Hi:
Many years ago, when C Band satellie service jsut started, I picked up a
couple of dish antennas from the Stanford Radio Astronomy filed just off of
280 opposite the big dish. They had 32 of these ten foot dishes tracking
the Sun and covering some thousands of feet. It was done using a single
centtrally located motor driving line shafts for right ascention, since the
dishes were mounted on shafts that were polar aligned. There was an
adjustment that looked like the head of a bolt that would adjust the
declination for the season of the year.
There was a thing that looked similar to the rear end from a car with a
second motor that could be used to move the dishes at a rate that was
different from the Earth's rotation and was used for end of the day return
and for morning sync.
If you have a decent clock and calander you could point at the Sun without
seeing it at all, which would be good when there's clouds. It's also good
not to be making any moves that are not necessary since that uses extra
electricity.
Note that the COS function is broad at the peak. For example you only have
a 10% loss if the panel is misaligned by 25.8 degrees, or 5% at 18.2
degrees, so tracking to sub degree accuracy is not needed. Since it takes
more power to start moving than to move continously it will take less energy
to make fewer moves, the ideal case is continous movement.
Just some ideas,
Brooke Clarke, N6GCE
http://www.RPC68.com
To UNSUBSCRIBE, just send mail to:
basicstamps-unsubscribe@yahoogroups.com
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Body of the message will be ignored.
Yahoo! Groups Links
Polar rotational alignment is of little use in following the Sun because, as
seen from Earth, the Sun follows the ecliptic, which is not in alignment with
the poles/equator Earth rotational movement, but rather is offset by 23.5
degrees (actually, it's the Earth's rotation that is offset from the plane of
the
solar system, but that's not the way it looks from here on Earth).
Hence, while a Polar rotation mount is good for star-tracking, it is not
useful for following the motions of planets or the Sun.
Also discussing solar tracking, not only does the sun "rise" to a different
maximal height at local noon each day depending on the time of year, the
compass point locations of sunrise and sunset also change daily.
At most any location on earth, the Sun will appear to rise directly from the
East and set directly to the West only on the equinoxes. The only places this
isn't strictly true are the poles (where, on an equinox, the sun will appear
to hug the horizon, rotating around you), but few of us will be setting up
Stamp Solar Trackers there. And it wouldn't work at all there half of the year,
anyway.
;-)
But, back to the basics of solar tracking. As mentioned by others before,
there are two motions going on: the Earth's daily rotation, and the Earth's
yearly revolution about the Sun.
If you made a device that rotated on a Polar-oriented axle once every 24
hours (a 24-hour clock) to synchronously follow the generally East-to-West
movement of the Sun, you would also need another to secondarily swing the angle
of
the axle around (at a 23.5 degree angle off Polar) to adjust for the ecliptic,
using sidereal ("star") time, making the axle describe a cone shape every
"star" day, mirroring the apparent wobble (vis a vis the Sun) of the Earth's
axis.
This one modification to the basic axle motion would then allow you to track
the sun with very good accuracy almost indefinitely, once you got everything
(Polar axle rotation, secondary axle motion, Sun) aligned and sync'ed up.
It may sound complex, but the general idea is not.
Copernicus figured out the gist of it nearly five hundred years ago.
David P. Reaves, III
TransLanTech Sound, LLC
Creators of the Award-Winning "Ariane Stereo Audio Leveler"
In a message dated Thursday, March 11, 2004 8:05 PM Brooke Clarke
[noparse]/noparse]mailto:[url=http://forums.parallaxinc.com/group/basicstamps/post?postID=HWjYZe6bVIfRT7L_EIo-jnX3CcivKpSQizrxk3OvvIhWyrzP4_ViV8--QJn9CcidIv1psqZen90]brooke@p...[/url wrote:
<<
> Hi:
>
> Many years ago, when C Band satellie service jsut started, I picked up a
> couple of dish antennas from the Stanford Radio Astronomy filed just off of
> 280 opposite the big dish.· They had 32 of these ten foot dishes tracking
> the Sun and covering some thousands of feet.· It was done using a single
> centtrally located motor driving line shafts for right ascention, since the
> dishes were mounted on shafts that were polar aligned.· There was an
> adjustment that looked like the head of a bolt that would adjust the
> declination for the season of the year.
>
> There was a thing that looked similar to the rear end from a car with a
> second motor that could be used to move the dishes at a rate that was
> different from the Earth's rotation and was used for end of the day return
> and for morning sync.
>
> If you have a decent clock and calander you could point at the Sun without
> seeing it at all, which would be good when there's clouds.· It's also good
> not to be making any moves that are not necessary since that uses extra
> electricity.
>
> Note that the COS function is broad at the peak.· For example you only have
> a 10% loss if the panel is misaligned by 25.8 degrees, or 5% at 18.2
> degrees, so tracking to sub degree accuracy is not needed.· Since it takes
> more power to start moving than to move continously it will take less energy
> to make fewer moves, the ideal case is continous movement.
>
> Just some ideas,
>
> Brooke Clarke, N6GCE
> http://www.RPC68.com
> >>
[noparse][[/noparse]Non-text portions of this message have been removed]
http://www.nasatech.com/Briefs/Jan04/NPO30872.html
There is also a link to a pdf that has a lot more detail. Basically,
it is a pinhole camera about the size of Lincoln's head on a penny.
The position of the sun's image as it moves across the 2-D CMOS
sensor array during the course of a few hours is determined and
number crunching determines the earth's rotation axis. It looks like
the interface to the chip is SPI, so the Stamp could read it (no,
they don't have them for sale at any price--this is taxpayer money).
Here the downloads are only possible from the U.S.A
????????????????????????????????????????????
"NTB TSP Download Services
Problem:
Sorry, this service is available only in the U.S.A. or in U.S. territories. You
appear to be attempting access from elsewhere or via an internet service
provider who is based elsewhere. "
????????????????????????????????????????????
regards Heinz Germany
Original Message
From: Tracy Allen
To: basicstamps@yahoogroups.com
Sent: Saturday, March 13, 2004 5:56 AM
Subject: [noparse][[/noparse]basicstamps] Re: Re: sun tracker
Here is a link to an interesting sundial-on-a-chip from Jet Propulsion Labs:
http://www.nasatech.com/Briefs/Jan04/NPO30872.html
There is also a link to a pdf that has a lot more detail. Basically,
it is a pinhole camera about the size of Lincoln's head on a penny.
The position of the sun's image as it moves across the 2-D CMOS
sensor array during the course of a few hours is determined and
number crunching determines the earth's rotation axis. It looks like
the interface to the chip is SPI, so the Stamp could read it (no,
they don't have them for sale at any price--this is taxpayer money).
To UNSUBSCRIBE, just send mail to:
basicstamps-unsubscribe@yahoogroups.com
from the same email address that you subscribed. Text in the Subject and Body
of the message will be ignored.
Yahoo! Groups Links
[noparse][[/noparse]Non-text portions of this message have been removed]
wrote:
> Hi
>
> Here the downloads are only possible from the U.S.A
>
> regards Heinz Germany
>
but, pdf files of the page are available !
check the files section of the basicstamps site under Digial Sundial.
Dave
for microstrain sensors on this site.
Dennis
Original Message
From: Tracy Allen [noparse]/noparse]mailto:[url=http://forums.parallaxinc.com/group/basicstamps/post?postID=o2yMtQ84Mo8YRVwioM3MXmqkCbbY5xqehivlLc1Vj38Kv9Dz5ZjTLa06DPBcCEj8WwDfwUty0rj2lczhrO86]tracy@e...[/url
Sent: Friday, March 12, 2004 8:57 PM
To: basicstamps@yahoogroups.com
Subject: [noparse][[/noparse]basicstamps] Re: Re: sun tracker
Here is a link to an interesting sundial-on-a-chip from Jet Propulsion
Labs:
http://www.nasatech.com/Briefs/Jan04/NPO30872.html
There is also a link to a pdf that has a lot more detail.
<deleted>
Funny, but I did find the SunAngle program. It was written 15 years ago
in Turbo Pascal 6.0 and, as usual with Pascal, it is small: 9K source,
13K compiled.
Latitude and longitude are considered to be constants, appropriate to my
part of the world, but can easily be converted to changing inputs or
prompted inputs.
As written, the program outputs a table for an arbitrary date, a
starting time, an ending time and a time-step, but this too can be
easily changed.
Mathematically it is simple and uses an approximation for the
time-equation which proved good enough. You can probably translate the
whole thing quite easily because Pascal is reasonably self-documenting.
The compiled program (done 15 years ago) still works in a DOS window of
a WINXP machine.
Let me know if you want it and I'll send it to you (and whoever is
interested) off-list.
Dov Yassky
5, Shapira Street
Tel Aviv 64358
Israel
Original Message
From: HSchwenk@w... [noparse]/noparse]mailto:[url=http://forums.parallaxinc.com/group/basicstamps/post?postID=Fw7zOy6EFqMs7hfBmUp4FMA2TvN-AlX1FbMObSVwoQK9YLRaD18cHZINWgrEznSB5lVJo68]HSchwenk@w...[/url
Sent: Friday, 12 March 2004 12:32 AM
To: basicstamps@yahoogroups.com
Subject: Re: [noparse][[/noparse]basicstamps] Re: sun tracker
Hi Dave, Rick, Dov, Jack and.....
thanks for Your quick answers
Dave
Your program is exactly what I am looking for. I don't understand Turbo
Pascal, but know somebody who may help me. Also, If You have the
calculation in usual math, I may have the chance to make my stamp to do
the job......
I would like that my stamp calculate first the azimuth and elevation
and then calculate the steps for my two step motors to move to.
In my program I like to use the time and date the latitude and
longitude.
As I don't need high angel resolution I can ignore the height above sea
level and may be simplify the calculation too.
Rick
How did You calculate This?: "peak of 50 degrees above my horizon. On
the first day of
winter it is a pitifull 26.5 degrees and the first day of summer it is
at 73.5 degrees"
...................................................................
The U.S. Naval Observatory site is interesting and the link there to
the Geonam Query page too.
My LATITUDE is 50° 04' 00" N
My LONGITUDE is 007° 27' 00" E
Rick, I would like my Stamp to calculate every think and move, my panels
faced to the sun, my be to move every minute a bit, even if there are
only clouds.
I used an shade-seeker before, but on a day where the sun cams out only
sometimes for some minutes, the shade-seeker didn't find the right
position and with a scan the whole thing moved up and down for nothing.
Then I added "a small automatic moving in interval in case the
shade-seeker could not see the sun..but I like the idea to find the
"sun's position" by calculation ..and .less hardware .
Any way I need a stamp to do some other job too:
**to turn the panels back in the night,
** passé reference switch
**to check if there is to much wind, to put the panels in save position
and fix them.
**and some alarm/safety functions.
...
ooh my e-mail gets long..
I am from germany but some panels should be used in Portugal too, so I
want to change only
LATITUDE and LONGITUDE in the program and it should wok.....
regards Heinz
Original Message
From: Dov Yassky
To: basicstamps@yahoogroups.com
Sent: Thursday, March 11, 2004 8:30 AM
Subject: RE: [noparse][[/noparse]basicstamps] Re: sun tracker
Heinz,
Many years ago I wrote a Turbo Pascal (or maybe it was Power Basic)
program that calculates sun azimuth and elevation for any latitude,
longitude, date and time. I don't remember if height above sea level
was considered too. The results were within 1 or 2 degrees compared
to
almanac values. I doubt if the program can practically be translated
into pbasic for stamp usage, but if you are interested, I'll try to
find
it.
Dov
Original Message
From: HSchwenk@w... [noparse]/noparse]mailto:[url=http://forums.parallaxinc.com/group/basicstamps/post?postID=Fw7zOy6EFqMs7hfBmUp4FMA2TvN-AlX1FbMObSVwoQK9YLRaD18cHZINWgrEznSB5lVJo68]HSchwenk@w...[/url
Sent: Wednesday, 10 December 2003 10:12 PM
To: basicstamps@yahoogroups.com
Subject: Re: [noparse][[/noparse]basicstamps] Re: sun tracker
Hi Rick and group
Your "two cents" are interesting!
they give help in my project. (playing with solar panels)
I would like to calculate the position of the sun, only
depending, on my position an the earth, and depending, on the date and
time.
I have an RF atomic time receiver (for Germany), 2 stepper motors and
a
stamp.
The clock with the stamp und the steppers work fine, but I have
problems
with the
calculations of the position of the sun.
Do You know the formula, or a link, or a similar project,
or even an pbasic program?
It would make it easier for me
Regards Heinz
Original Message
From: Richard C. Walter Jr.
To: basicstamps@yahoogroups.com
Sent: Wednesday, March 10, 2004 2:46 AM
Subject: Re: [noparse][[/noparse]basicstamps] Re: sun tracker
I thought I would throw my two cents into the array (sorry for the
pun).
The earth actually turns about 361 degrees per day. It would be
easier to
explain with a diagram but here goes. Since the earth rotates on its
axis
and revolves around the sun, the earth must turn a little more than
360
degrees per day to play "catch up" to the sun. If you think of the
earth
moving in its orbit aorund the sun, it moves around 1 degree per day
(360
degrees in 365 days). Since the earth moved through space about 1
degree,
it must turn on its axis an extra degree (361) to point back to the
sun.
In other words, if you had a sundial on the earth indicating it is
noon, the
earth would turn about 361 degrees to have the sundial say it is
noon
again.
This is one reason why we have the equation of time. (The difference
between
clock time and sundial time). The sun runs "fast" and "slow" at
different
times during the year because the of the earth turning (rotating) a
different amount than 360 degrees per day.
Also, at the solstices, the sun appears to move parallel to the
ecliptic
(sun's path on the celestial sphere) so the sun moves a greater
distance
eastward per day. At the equinoxes, the sun's path is more of a
right
angle
to the ecliptic (sun is moving above or below the celestial equator)
so it
does not move as far eastward as other times of the year.
Look for "analemma" with google and check out the very good
explainations
regarding this process. The analemma is a figure 8 that show the
equation of
time on the X axis and the declination of the sun (or the latitude
of
sun's
rays 90 degrees overhead) for each day of the year on the Y axis.
It
used
to be commonly found on old maps and globes in the Pacific Ocean
where
there
was nothing but water!
Finally, since we call one day (24 hours) the time it takes from
sunrise to
sunrise it does not matter if it is 360 or 361 degrees. Everyone is
correct
about the sun moving 1 degree every 4 minutes, but you must remember
that is
an average.
If you want to refer to a day as the time it takes the earth to turn
exactly
360 degrees, we are talking about a sidereal day (star time). A
sidereal
clock runs faster than a "sun" clock (like on the wall). A sidereal
day is
approx. 23 hours, 56 minutes, and 4.09 seconds.
If you view a star above a branch of a tree tonight at 9 PM (on your
regular
clock) and go out each night at 9 PM, the star will continually move
away
from the branch. If you went out at 9 hours on your sidereal clock
each
night, the star will be in the exact same position relative to the
tree,
night after night.
By the way, solar clocks (wall clocks) and sidereal clocks agree on
one day,
the autumnal equinox.
Sorry you got me started. I'll crawl back in my hole and lurk
another
3 or
4 years.
Rick
To UNSUBSCRIBE, just send mail to:
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please email to hellkat909@y...
Dov Yassky <dovy@b...> wrote:
Heinz,
Funny, but I did find the SunAngle program. It was written 15 years ago
in Turbo Pascal 6.0 and, as usual with Pascal, it is small: 9K source,
13K compiled.
Latitude and longitude are considered to be constants, appropriate to my
part of the world, but can easily be converted to changing inputs or
prompted inputs.
As written, the program outputs a table for an arbitrary date, a
starting time, an ending time and a time-step, but this too can be
easily changed.
Mathematically it is simple and uses an approximation for the
time-equation which proved good enough. You can probably translate the
whole thing quite easily because Pascal is reasonably self-documenting.
The compiled program (done 15 years ago) still works in a DOS window of
a WINXP machine.
Let me know if you want it and I'll send it to you (and whoever is
interested) off-list.
Dov Yassky
5, Shapira Street
Tel Aviv 64358
Israel
Original Message
From: HSchwenk@w... [noparse]/noparse]mailto:[url=http://forums.parallaxinc.com/group/basicstamps/post?postID=Ig9a-w9ceCJtx0La40lnywEufK5thymcR2WGQUcvYtB-N3q7SZ258M4T7B0DjvKycx3HOMT-f4c]HSchwenk@w...[/url
Sent: Friday, 12 March 2004 12:32 AM
To: basicstamps@yahoogroups.com
Subject: Re: [noparse][[/noparse]basicstamps] Re: sun tracker
Hi Dave, Rick, Dov, Jack and.....
thanks for Your quick answers
Dave
Your program is exactly what I am looking for. I don't understand Turbo
Pascal, but know somebody who may help me. Also, If You have the
calculation in usual math, I may have the chance to make my stamp to do
the job......
I would like that my stamp calculate first the azimuth and elevation
and then calculate the steps for my two step motors to move to.
In my program I like to use the time and date the latitude and
longitude.
As I don't need high angel resolution I can ignore the height above sea
level and may be simplify the calculation too.
Rick
How did You calculate This?: "peak of 50 degrees above my horizon. On
the first day of
winter it is a pitifull 26.5 degrees and the first day of summer it is
at 73.5 degrees"
...................................................................
The U.S. Naval Observatory site is interesting and the link there to
the Geonam Query page too.
My LATITUDE is 50° 04' 00" N
My LONGITUDE is 007° 27' 00" E
Rick, I would like my Stamp to calculate every think and move, my panels
faced to the sun, my be to move every minute a bit, even if there are
only clouds.
I used an shade-seeker before, but on a day where the sun cams out only
sometimes for some minutes, the shade-seeker didn't find the right
position and with a scan the whole thing moved up and down for nothing.
Then I added "a small automatic moving in interval in case the
shade-seeker could not see the sun..but I like the idea to find the
"sun's position" by calculation ..and .less hardware .
Any way I need a stamp to do some other job too:
**to turn the panels back in the night,
** passé reference switch
**to check if there is to much wind, to put the panels in save position
and fix them.
**and some alarm/safety functions.
...
ooh my e-mail gets long..
I am from germany but some panels should be used in Portugal too, so I
want to change only
LATITUDE and LONGITUDE in the program and it should wok.....
regards Heinz
Original Message
From: Dov Yassky
To: basicstamps@yahoogroups.com
Sent: Thursday, March 11, 2004 8:30 AM
Subject: RE: [noparse][[/noparse]basicstamps] Re: sun tracker
Heinz,
Many years ago I wrote a Turbo Pascal (or maybe it was Power Basic)
program that calculates sun azimuth and elevation for any latitude,
longitude, date and time. I don't remember if height above sea level
was considered too. The results were within 1 or 2 degrees compared
to
almanac values. I doubt if the program can practically be translated
into pbasic for stamp usage, but if you are interested, I'll try to
find
it.
Dov
Original Message
From: HSchwenk@w... [noparse]/noparse]mailto:[url=http://forums.parallaxinc.com/group/basicstamps/post?postID=Ig9a-w9ceCJtx0La40lnywEufK5thymcR2WGQUcvYtB-N3q7SZ258M4T7B0DjvKycx3HOMT-f4c]HSchwenk@w...[/url
Sent: Wednesday, 10 December 2003 10:12 PM
To: basicstamps@yahoogroups.com
Subject: Re: [noparse][[/noparse]basicstamps] Re: sun tracker
Hi Rick and group
Your "two cents" are interesting!
they give help in my project. (playing with solar panels)
I would like to calculate the position of the sun, only
depending, on my position an the earth, and depending, on the date and
time.
I have an RF atomic time receiver (for Germany), 2 stepper motors and
a
stamp.
The clock with the stamp und the steppers work fine, but I have
problems
with the
calculations of the position of the sun.
Do You know the formula, or a link, or a similar project,
or even an pbasic program?
It would make it easier for me
Regards Heinz
Original Message
From: Richard C. Walter Jr.
To: basicstamps@yahoogroups.com
Sent: Wednesday, March 10, 2004 2:46 AM
Subject: Re: [noparse][[/noparse]basicstamps] Re: sun tracker
I thought I would throw my two cents into the array (sorry for the
pun).
The earth actually turns about 361 degrees per day. It would be
easier to
explain with a diagram but here goes. Since the earth rotates on its
axis
and revolves around the sun, the earth must turn a little more than
360
degrees per day to play "catch up" to the sun. If you think of the
earth
moving in its orbit aorund the sun, it moves around 1 degree per day
(360
degrees in 365 days). Since the earth moved through space about 1
degree,
it must turn on its axis an extra degree (361) to point back to the
sun.
In other words, if you had a sundial on the earth indicating it is
noon, the
earth would turn about 361 degrees to have the sundial say it is
noon
again.
This is one reason why we have the equation of time. (The difference
between
clock time and sundial time). The sun runs "fast" and "slow" at
different
times during the year because the of the earth turning (rotating) a
different amount than 360 degrees per day.
Also, at the solstices, the sun appears to move parallel to the
ecliptic
(sun's path on the celestial sphere) so the sun moves a greater
distance
eastward per day. At the equinoxes, the sun's path is more of a
right
angle
to the ecliptic (sun is moving above or below the celestial equator)
so it
does not move as far eastward as other times of the year.
Look for "analemma" with google and check out the very good
explainations
regarding this process. The analemma is a figure 8 that show the
equation of
time on the X axis and the declination of the sun (or the latitude
of
sun's
rays 90 degrees overhead) for each day of the year on the Y axis.
It
used
to be commonly found on old maps and globes in the Pacific Ocean
where
there
was nothing but water!
Finally, since we call one day (24 hours) the time it takes from
sunrise to
sunrise it does not matter if it is 360 or 361 degrees. Everyone is
correct
about the sun moving 1 degree every 4 minutes, but you must remember
that is
an average.
If you want to refer to a day as the time it takes the earth to turn
exactly
360 degrees, we are talking about a sidereal day (star time). A
sidereal
clock runs faster than a "sun" clock (like on the wall). A sidereal
day is
approx. 23 hours, 56 minutes, and 4.09 seconds.
If you view a star above a branch of a tree tonight at 9 PM (on your
regular
clock) and go out each night at 9 PM, the star will continually move
away
from the branch. If you went out at 9 hours on your sidereal clock
each
night, the star will be in the exact same position relative to the
tree,
night after night.
By the way, solar clocks (wall clocks) and sidereal clocks agree on
one day,
the autumnal equinox.
Sorry you got me started. I'll crawl back in my hole and lurk
another
3 or
4 years.
Rick
To UNSUBSCRIBE, just send mail to:
basicstamps-unsubscribe@yahoogroups.com
from the same email address that you subscribed. Text in the
Subject
and Body of the message will be ignored.
Yahoo! Groups Links
[noparse][[/noparse]Non-text portions of this message have been removed]
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[noparse][[/noparse]Non-text portions of this message have been removed]
But it appears that where the sun is at any given time will not be where the
ecliptic was/will be a few hours before or after, since the ecliptic also
appears to shift throughout the day.
The ecliptic can be imagined as like a big hula hoop, that appears to swing
up and down and around roughly once a day. It's hard to tell it's shifting,
because there aren't that many celestial bodies riding the ecliptic to show its
motion obviously.
The ecliptic (the average plane of the orbits of the Earth, moon and the
planets about the Sun] only *appears* to vary when viewed from Earth, due to the
23.5 degree offset of Earth's rotation from the ecliptic.
The ecliptic for a given location's Earth latitude is "locked in," and quite
predictable. Its maximum apparent height in degrees above horizon (always seen
directly due South, in the Northern Hemisphere) never changes, though the
time of day of maximum does, depending upon the day of the year.
This maximum angle above horizon can be simply computed: it is equal to (90
minus the degrees in latitude of the location) + 23.5.
For example, if you live in New York City, the latitude there is 41N.
Subtracting 41 from 90, equals 49; add 23.5 to 49, and you know that the
ecliptic
reaches a maximum of 72.5 degrees above horizon in the southern sky over NYC.
The time of day that this maximum occurs changes through the year. On the
summer solstice the maximum 'height' due South is at local noon. This makes
sense; everyone knows, the sun gets highest on the longest day of the year,
about
the 21st of June (for the Northern Hemisphere; December 21 in the Southern
Hemisphere).
On the winter solstice, the maximum height of the ecliptic (still due South,
it's ALWAYS due South) is at midnight. On the Vernal (spring) equinox, the
maximum due south is at 6AM, and on the Autumnal equinox, it's at 6:00PM.
For this reason, the brightest, highest full moon is the one that's closest
to December 21 every year. But the highest *half* moon will be on one of the
equinoxes, depending on whether the moon is waxing or waning.
Hey, a MOON tracker... now THERE's a PROJECT!!!
David P. Reaves, III
TransLanTech Sound, LLC
Creators of the Award-Winning "Ariane Stereo Audio Leveler"
In a message dated Wednesday, March 10, 2004 2:46 AM, Richard C. Walter Jr.
writes:
> <<
> · · I thought I would throw my two cents into the array (sorry for the pun).
>
> · · The earth actually turns about 361 degrees per day.· It would be easier
> to
> · · explain with a diagram but here goes. Since the earth rotates on its
> axis
> · · and revolves around the sun, the earth must turn a little more than 360
> · · degrees per day to play "catch up" to the sun.· If you think of the
> earth
> · · moving in its orbit aorund the sun, it moves around 1 degree per day
> · (360 degrees in 365 days).· Since the earth moved through space about
> 1
> · degree, it must turn on its axis an extra degree (361) to point back
> to the
> · sun.
>
> · · In other words, if you had a sundial on the earth indicating it is noon,
> the
> · · earth would turn about 361 degrees to have the sundial say it is noon
> again.
> · · This is one reason why we have the equation of time. (The difference
> between
> · · clock time and sundial time).· The sun runs "fast" and "slow" at
> different
> · · times during the year because the of the earth turning (rotating) a
> · · different amount than 360 degrees per day.
>
> · · Also, at the solstices, the sun appears to move parallel to the ecliptic
> · · (sun's path on the celestial sphere) so the sun moves a greater distance
> · · eastward per day.· At the equinoxes, the sun's path is more of a right
> angle
> · · to the ecliptic (sun is moving above or below the celestial equator) so
> it
> · · does not move as far eastward as other times of the year.
> >>
[noparse][[/noparse]Non-text portions of this message have been removed]