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Heliocentric Julian Date calculation

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Mark Blackford
Mark Blackford's picture
Heliocentric Julian Date calculation

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

Herr_Alien
Herr_Alien's picture
These two links should

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.

Mark Blackford
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HJD

Thanks Alexandru,

I'll take a look at these. Cheers,

Mark

BGW
BGW's picture
HJD spreadsheet

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

www.lewcook.com/SUNTime.htm

Cheers,  Gary Billings

Mark Blackford
Mark Blackford's picture
HJD

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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