Day of the week calculation (from the julian day)
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Posts: 46,084
Hi,
Does anyone know of a formula or algorithm to calculate the day of
the week from the julian day? I am familiar with the "doomsday"
algorithm and know the formula for that given the year.
any help would be appreciated.
Thanks,
RP
Does anyone know of a formula or algorithm to calculate the day of
the week from the julian day? I am familiar with the "doomsday"
algorithm and know the formula for that given the year.
any help would be appreciated.
Thanks,
RP
Comments
Check out Tracy's site above all the Julian stuff you want and more much
more!
Original Message
From: <rpsu279@y...>
To: <basicstamps@yahoogroups.com>
Sent: November 23, 2001 6:20 PM
Subject: [noparse][[/noparse]basicstamps] Day of the week calculation (from the julian day)
| Hi,
| Does anyone know of a formula or algorithm to calculate the day of
| the week from the julian day? I am familiar with the "doomsday"
| algorithm and know the formula for that given the year.
|
| any help would be appreciated.
|
| Thanks,
| RP
|
|
|
| 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.
|
|
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|
|
I even have printouts of most of his stuff. I refer to it constantly.
However, I could not find any mention of "day of the week" (Sunday,
Monday, etc.) given the date (or julian date). I know he has code for
finding out the month and day (value) from the julian day of the
year.
--- In basicstamps@y..., "Larry Gaminde" <lgaminde@t...> wrote:
> http://www.emesys.com/BS2math4.htm
>
> Check out Tracy's site above all the Julian stuff you want and more
much
> more!
>
>
>
Original Message
> From: <rpsu279@y...>
> To: <basicstamps@y...>
> Sent: November 23, 2001 6:20 PM
> Subject: [noparse][[/noparse]basicstamps] Day of the week calculation (from the julian
day)
>
>
> | Hi,
> | Does anyone know of a formula or algorithm to calculate the day of
> | the week from the julian day? I am familiar with the "doomsday"
> | algorithm and know the formula for that given the year.
> |
> | any help would be appreciated.
> |
> | Thanks,
> | RP
> |
> |
> |
> | To UNSUBSCRIBE, just send mail to:
> | basicstamps-unsubscribe@y...
> | from the same email address that you subscribed. Text in the
Subject and
> Body of the message will be ignored.
> |
> |
> | Your use of Yahoo! Groups is subject to
http://docs.yahoo.com/info/terms/
> |
> |
Original Message
From: <rpsu279@y...>
To: <basicstamps@yahoogroups.com>
Sent: November 23, 2001 8:35 PM
Subject: [noparse][[/noparse]basicstamps] Re: Day of the week calculation (from the julian day)
| Oh, yeah! I've been there. Tracy's site is the best I've seen so far.
| I even have printouts of most of his stuff. I refer to it constantly.
| However, I could not find any mention of "day of the week" (Sunday,
| Monday, etc.) given the date (or julian date). I know he has code for
| finding out the month and day (value) from the julian day of the
| year.
|
| --- In basicstamps@y..., "Larry Gaminde" <lgaminde@t...> wrote:
| > http://www.emesys.com/BS2math4.htm
| >
| > Check out Tracy's site above all the Julian stuff you want and more
| much
| > more!
| >
| >
| >
Original Message
| > From: <rpsu279@y...>
| > To: <basicstamps@y...>
| > Sent: November 23, 2001 6:20 PM
| > Subject: [noparse][[/noparse]basicstamps] Day of the week calculation (from the julian
| day)
| >
| >
| > | Hi,
| > | Does anyone know of a formula or algorithm to calculate the day of
| > | the week from the julian day? I am familiar with the "doomsday"
| > | algorithm and know the formula for that given the year.
| > |
| > | any help would be appreciated.
| > |
| > | Thanks,
| > | RP
| > |
| > |
| > |
| > | To UNSUBSCRIBE, just send mail to:
| > | basicstamps-unsubscribe@y...
| > | from the same email address that you subscribed. Text in the
| Subject and
| > Body of the message will be ignored.
| > |
| > |
| > | Your use of Yahoo! Groups is subject to
| http://docs.yahoo.com/info/terms/
| > |
| > |
|
|
| 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.
|
|
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|
|
>Does anyone know of a formula or algorithm to calculate the day of
>the week from the julian day? I am familiar with the "doomsday"
>algorithm and know the formula for that given the year.
>
>any help would be appreciated.
>
>Thanks,
>RP
That's easy! You just divide the Julian day by 7 and look at the
remainder. Say you count successive days from "1" on January 1,
2001. That was a Monday. If you divide the Julian day by 7 and the
remainder is one, that too is a Monday. 2=Tuesday etc. That goes if
you continue the count on into years in the future.
-- Tracy
--- In basicstamps@y..., Tracy Allen <tracy@e...> wrote:
> >Hi,
> >Does anyone know of a formula or algorithm to calculate the day of
> >the week from the julian day? I am familiar with the "doomsday"
> >algorithm and know the formula for that given the year.
> >
> >any help would be appreciated.
> >
> >Thanks,
> >RP
>
> That's easy! You just divide the Julian day by 7 and look at the
> remainder. Say you count successive days from "1" on January 1,
> 2001. That was a Monday. If you divide the Julian day by 7 and the
> remainder is one, that too is a Monday. 2=Tuesday etc. That goes
if
> you continue the count on into years in the future.
>
> -- Tracy
what I was thinking
using the date from 1950 I think that's how far back Tracy's Julian stuff
goes back to
6-24-01 = 18438 Julian days 6-25-01 is 18439 pick a date that is before
your last date needing to be checked and pick a day that is / 7 like 18210
for example then using a for next loop like below you will check for
remainder if there is a remainder the loop continues on until remainder = 0,
when = to 0 then I will be how many days or group of 7 days from your
starting point which you pick and know what day you started with then using
a lookup table or something of you choice. this is not working code but I
hope you can use the Idea I have not been working with the stamps for a few
months so I'm a bit rusty on the code
for i = 0 to 6
day = (18438 - 18210) - i
day = day //7
if day > 0 next
day += i
Original Message
From: <rpsu279@y...>
To: <basicstamps@yahoogroups.com>
Sent: November 25, 2001 6:29 PM
Subject: [noparse][[/noparse]basicstamps] Re: Day of the week calculation (from the julian day)
| That's only for this year, right?
|
| --- In basicstamps@y..., Tracy Allen <tracy@e...> wrote:
| > >Hi,
| > >Does anyone know of a formula or algorithm to calculate the day of
| > >the week from the julian day? I am familiar with the "doomsday"
| > >algorithm and know the formula for that given the year.
| > >
| > >any help would be appreciated.
| > >
| > >Thanks,
| > >RP
| >
| > That's easy! You just divide the Julian day by 7 and look at the
| > remainder. Say you count successive days from "1" on January 1,
| > 2001. That was a Monday. If you divide the Julian day by 7 and the
| > remainder is one, that too is a Monday. 2=Tuesday etc. That goes
| if
| > you continue the count on into years in the future.
| >
| > -- Tracy
|
|
| 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.
|
|
| Your use of Yahoo! Groups is subject to http://docs.yahoo.com/info/terms/
|
|
here
using the Julian date formula of Tracy's you get a number starting I think
in the year 1950. What I did was take a date that goes back as far as you
last date needed, and get the Julian date for it like 18210 which needs to
be divisible by 7, so taking the date 6-24-01 the Julian number is 18438
minus your starting date 18210 ( you also need to know the day for this
date ) then minus I ( I is number of days from your start point of Sunday or
what ever day you pick ) then // 7 look for remainder. If remainder is = 0
you have the same day as you start point plus I so I = day of week 0 =
Sunday 1= Monday 2 = Tuesday and 6 = Saturday you could use a lookup table
or just use the # to represent the day
for I = 0 to 6
day = ( Julian date(18438) - starting Julian date(18210) ) - I
day = day //7 : look for remainder
if day = 0 then I = to the day of the week 0 being Sunday or what ever it
really works out to.
Original Message
From: <rpsu279@y...>
To: <basicstamps@yahoogroups.com>
Sent: November 25, 2001 6:29 PM
Subject: [noparse][[/noparse]basicstamps] Re: Day of the week calculation (from the julian day)
| That's only for this year, right?
|
| --- In basicstamps@y..., Tracy Allen <tracy@e...> wrote:
| > >Hi,
| > >Does anyone know of a formula or algorithm to calculate the day of
| > >the week from the julian day? I am familiar with the "doomsday"
| > >algorithm and know the formula for that given the year.
| > >
| > >any help would be appreciated.
| > >
| > >Thanks,
| > >RP
| >
| > That's easy! You just divide the Julian day by 7 and look at the
| > remainder. Say you count successive days from "1" on January 1,
| > 2001. That was a Monday. If you divide the Julian day by 7 and the
| > remainder is one, that too is a Monday. 2=Tuesday etc. That goes
| if
| > you continue the count on into years in the future.
| >
| > -- Tracy
|
|
| 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.
|
|
| Your use of Yahoo! Groups is subject to http://docs.yahoo.com/info/terms/
|
|
Hi Ravi,
No, the Julian Day Number is sequential for a period of years. The
base date for astronomers is 1 January 4713 BC on the Julian
Calendar. Do you need to go that far back?! More convenient for a
Stamp is a base date of January 1, 2001.
Here is a subroutine that calculates the Julian Day Number from that
date (1-Jan-2001, as day #1) to any other date in the 21st century up
to Dec. 31, 2099. JD="day of year", JDN="days counted from 1/1/01"
example 11/25/01 is JD=329, JDN=329
example 11/25/99 is JD=329, JDN=36123
' returns Julian Day Number JDN for years 2001 to 2099
' Julian Day is sequential for current year.
' DD/MM/YY is day/month/year as integers (not BCD)
julian:
JD=MM-1*30+(MM/9+MM/2)-(MM max 3/3*(YY//4 max 1 +1))+ DD
JDN=JD+(YY-1*365)+(YY-1/4)
return
That is the same as the routine on my web page
<http://www.emesys.com/BS2math4.htm #JulianDate>, except there I used
1950 as the base date and covered up to 2048. Had to cover Y2K then,
back in the 20th century (hehe). To find the day of the week, divide
the JDN by 7 and look at the remainder:
DOW=JDN//7
1=Monday, 2=Tuesday, 3=Wed. 4=Thurs 5=Fri 6=Sat 0=Sunday
329//7 = 0 Sunday 25-Nov-2001
36123//7 = 3 Wednesday 25-Nov-2099
-- regards,
Tracy Allen
electronically monitored ecosystems
mailto:tracy@e...
http://www.emesystems.com
>
>--- In basicstamps@y..., Tracy Allen <tracy@e...> wrote:
> > >Hi,
> > >Does anyone know of a formula or algorithm to calculate the day of
> > >the week from the julian day? I am familiar with the "doomsday"
> > >algorithm and know the formula for that given the year.
> > >
> > >any help would be appreciated.
> > >
> > >Thanks,
> > >RP
> >
> > That's easy! You just divide the Julian day by 7 and look at the
> > remainder. Say you count successive days from "1" on January 1,
> > 2001. That was a Monday. If you divide the Julian day by 7 and the
> > remainder is one, that too is a Monday. 2=Tuesday etc. That goes
>if
> > you continue the count on into years in the future.
> >
> > -- Tracy
Thanks again for your formula. I ran a program in regard to that and
it works like a charm.
--- In basicstamps@y..., Tracy Allen <tracy@e...> wrote:
>
>
> >That's only for this year, right?
>
> Hi Ravi,
>
> No, the Julian Day Number is sequential for a period of years. The
> base date for astronomers is 1 January 4713 BC on the Julian
> Calendar. Do you need to go that far back?! More convenient for a
> Stamp is a base date of January 1, 2001.
I don't need to go back at all. In fact, as long as it works for this
year, it is good.
>
> Here is a subroutine that calculates the Julian Day Number from
that
> date (1-Jan-2001, as day #1) to any other date in the 21st century
up
> to Dec. 31, 2099. JD="day of year", JDN="days counted from 1/1/01"
> example 11/25/01 is JD=329, JDN=329
> example 11/25/99 is JD=329, JDN=36123
>
>
> ' returns Julian Day Number JDN for years 2001 to 2099
> ' Julian Day is sequential for current year.
> ' DD/MM/YY is day/month/year as integers (not BCD)
> julian:
> JD=MM-1*30+(MM/9+MM/2)-(MM max 3/3*(YY//4 max 1 +1))+ DD
> JDN=JD+(YY-1*365)+(YY-1/4)
> return
>
> That is the same as the routine on my web page
> <http://www.emesys.com/BS2math4.htm #JulianDate>, except there I
used
> 1950 as the base date and covered up to 2048. Had to cover Y2K
then,
> back in the 20th century (hehe). To find the day of the week,
divide
> the JDN by 7 and look at the remainder:
> DOW=JDN//7
> 1=Monday, 2=Tuesday, 3=Wed. 4=Thurs 5=Fri 6=Sat 0=Sunday
>
> 329//7 = 0 Sunday 25-Nov-2001
> 36123//7 = 3 Wednesday 25-Nov-2099
Great. That will work just fine.
>
> -- regards,
> Tracy Allen
> electronically monitored ecosystems
> mailto:tracy@e...
> http://www.emesystems.com
>
>
> >
> >--- In basicstamps@y..., Tracy Allen <tracy@e...> wrote:
> > > >Hi,
> > > >Does anyone know of a formula or algorithm to calculate the
day of
> > > >the week from the julian day? I am familiar with the "doomsday"
> > > >algorithm and know the formula for that given the year.
> > > >
> > > >any help would be appreciated.
> > > >
> > > >Thanks,
> > > >RP
> > >
> > > That's easy! You just divide the Julian day by 7 and look at
the
> > > remainder. Say you count successive days from "1" on January
1,
> > > 2001. That was a Monday. If you divide the Julian day by 7 and
the
> > > remainder is one, that too is a Monday. 2=Tuesday etc. That
goes
> >if
> > > you continue the count on into years in the future.
> > >
> > > -- Tracy