RE: GJD to HJD

["Creager, Robert S" <CreagRS@LOUISVILLE.STORTEK.COM>]

Hey Michael,

Depending on your level of interest, I'd be happy to do this, or help you do
this, or watch you do this ;-)

I had thoughts of using Math::BigInt (just for grins -
http://search.cpan.org/search?dist=Math-BigInt - it does 'floats' also) for
arbitrary percision, but then you'd have to create your own trig functions
and such...

Cheers,
Rob

> -----Original Message-----
> From: Michael Koppelman [mailto:lolife@bitstream.net]
> Sent: Tuesday, June 18, 2002 9:15 AM
> To: TASS
> Subject: Re: GJD to HJD
> 
> 
> I don't know if this is interesting to y'all or not...
> 
> After more discussions with Patrick Wallace of SLA, I now 
> have a program 
> that computes the heliocentric correction to an accuracy of 
> less than 1/2 
> of a second. Note that I'm using his routines verbatim, the 
> hard part for 
> me was getting the JD into a format usable in his routines, 
> which is year,
>   day of year and fractional day. Thus, what I've learned 
> would still be 
> useful if we use C-wrappers around the FORTRAN SLA library.
> 
> The numbers from Taichi Kato and Lew Cook (for the example 
> I'm working on)
>   were also under 1/2 sec of accuracy. This is compared to 
> numbers Patrick 
> gave me.
> 
> Patrick suggested that I port his algorithms to perl. If I am 
> true to the 
> routines, I think we can have a win-win: the algorithms have been 
> extensively tested, but we have a simple perl script that can 
> run without 
> dependencies. I'm going to give this a shot, but don't hold 
> your breath!
> 
> Cheers,
> Michael Koppelman
> 
>