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Heliocentric Julian Date calculation

Mark Blackford's picture
Mark Blackford
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Joined: 2011-01-15

Hi All,

not sure if this is the right forum to ask my questions but it does relate to my observations of eclipsing binaries. I am aware of several websites where Julian dates can be entered from which Heliocentric Julian Dates are then calculated but I want to do the calculation in a my own Excel spreadsheet. 

Can anyone provide the relevant equations? The only input parameters as far as I can see would be JD and the object's RA and Dec. 

Any advice would be much appreciated. Cheers,

Mark

These two links should
Herr_Alien's picture
Herr_Alien
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Joined: 2012-04-24

These two links should help:

http://en.wikipedia.org/wiki/Heliocentric_Julian_Day

http://en.wikipedia.org/wiki/Position_of_the_Sun

You'll need the second link to compute the RA and DEC of the sun.

HJD spreadsheet
BGW's picture
BGW
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Joined: 2010-10-03

Here's one:  I haven't used it myself...

www.lewcook.com/SUNTime.htm

Cheers,  Gary Billings

HJD
Mark Blackford's picture
Mark Blackford
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Joined: 2011-01-15

Thanks Alexandru,

I'll take a look at these. Cheers,

Mark

HJD
Mark Blackford's picture
Mark Blackford
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Joined: 2011-01-15

Thanks Gary,

I've used Lew Cook's spreadsheets, very useful but the details of calculations are hidden. I was contacted off-line by a colleague who provided his spreadsheet based on info in Astronomical Algorithms by Jean Meeus, so I think I have what I've been looking for. Cheers,

Mark

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