[Coco] Looking for CoCo astronomy and space software.

[jdaggett at gate.net]

Alex

You can use what ever you wish to mark time. Every astronomical program 
I have seen has done a conversion of Gregorian Calendar date and time to 
Julian. From there the conversion is to either Local Sidereal or Grenwich 
Mean Sidereal time. 

Now if you want to keep time some other method so bo it. What ever floats 
your boat. There are lioteraly hundreds of ways to do it. 

james


On 19 Jan 2004 at 14:23, Alex wrote:

From:           	Theodore (Alex) Evans <alxevans at concentric.net>
Subject:        	Re: [Coco] Looking for CoCo astronomy and space 
software.
Date sent:      	Mon, 19 Jan 2004 14:23:49 -1000
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> 
> On Jan 19, 2004, at 1:21 PM, jdaggett at gate.net wrote:
> 
> > Alex
> >
> > The only way to do planetarium style programs is to convert
> > Gregorian calendar date to Julian calendar. By using Julian dates
> > and scaling one can predict with some degree of certaincy the skies
> > as they appeared over say the Middle  East in 10,000 BCE. Or the
> > skies over New York city in 10,000 CE. In fact in 12,000 CE the star
> > Vega in the constellation Lyra will be the North Star. During the
> > fall in the early evening it is the brightest star in the northern
> > skies.
> 
> There is a confusing term.  Unfortunately todays Julian date can be
> interpreted as 2453024 (the one you mean), 2004019, or 6 Jan 2004. 
> While (astronomical) Julian dates are the typical way of doing such
> things, they are hardly the only way.  For example one could easily
> use a 64-bit signed Unix date.
> 
> 
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