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Re: Local solar time [message #39975 is a reply to message #39904]

Tue, 29 June 2004 11:54

Craig Markwardt
Messages: 1869
Registered: November 1996

Senior Member

David Oesch <oesch@giub.nospam.unibe.ch> writes:

>> With some massaging, I think you can get what you want by using the
>> IDL Astronomy Library routines SUNPOS to compute the (RA, DEC)
>> position of the sun, and CT2LST, to compute the local mean sidereal
>> time, and then use the definition,
>>
>>
>>
> I got the Sun Azimuth and Sun zenith already, and use the LMST routine
> from the Johns Hopkins University/Applied Physics Laboratory to
> calculate the local mean sidereal time. Is the "local mean sideral time"
> the same as "local solar time"?

No, that's why I supplied the formula below. The local hour angle of
the sun is effectively the local solar time, plus a constant:

>> local hour angle of the sun = local sidereal time[1] - RA of sun[2]

and local apparent solar time = local hour angle + 12 hours

[1] is calculated with CT2LST
[2] is calculated with SUNPOS

Craig

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Craig B. Markwardt, Ph.D. EMAIL: craigmnet@REMOVEcow.physics.wisc.edu
Astrophysics, IDL, Finance, Derivatives | Remove "net" for better response
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[Message index]

		Local solar time By: David Oesch on Mon, 28 June 2004 02:01
		Re: Local solar time By: David Fanning on Wed, 30 June 2004 06:29
		Re: Local solar time By: kuyper on Wed, 30 June 2004 05:59
		Re: Local solar time By: Craig Markwardt on Tue, 29 June 2004 16:36
		Re: Local solar time By: James Kuyper on Tue, 29 June 2004 13:19
		Re: Local solar time By: Craig Markwardt on Tue, 29 June 2004 12:13
		Re: Local solar time By: Craig Markwardt on Tue, 29 June 2004 11:58
		Re: Local solar time By: Craig Markwardt on Tue, 29 June 2004 11:54
		Re: Local solar time By: Michael Wallace on Tue, 29 June 2004 08:28
		Re: Local solar time By: Haje Korth on Tue, 29 June 2004 08:00
		Re: Local solar time By: Haje Korth on Tue, 29 June 2004 05:12
		Re: Local solar time By: David Oesch on Tue, 29 June 2004 05:12
		Re: Local solar time By: Haje Korth on Tue, 29 June 2004 05:09
		Re: Local solar time By: James Kuyper on Tue, 29 June 2004 04:51
		Re: Local solar time By: Craig Markwardt on Tue, 29 June 2004 02:48
		Re: Local solar time By: David Oesch on Mon, 28 June 2004 23:31
		Re: Local solar time By: Craig Markwardt on Mon, 28 June 2004 20:46
		Re: Local solar time By: Haje Korth on Mon, 28 June 2004 08:07

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