[Coco] Looking for CoCo astronomy and space software.

[jdaggett at gate.net]

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. 

james
 

On 19 Jan 2004 at 12:29, 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 12:29:36 -1000
To:             	gene.heskett at verizon.net,
	CoCoList for Color Computer Enthusiasts 
<coco at maltedmedia.com>
Copies to:      	Send reply to:  	CoCoList for Color Computer 
Enthusiasts <coco at maltedmedia.com>
	<mailto:coco-
request at maltedmedia.com?subject=unsubscribe>
	<mailto:coco-
request at maltedmedia.com?subject=subscribe>

> On Jan 19, 2004, at 12:12 PM, Gene Heskett wrote:
> 
> > There was an solar or lunar eclipse predictor program published
> > maybe 15 years ago in IIRC Byte, written in basic-5.22, whatever
> > that was. It looked a lot like truebasic in styling.  I had  fun
> > converting it to C srcs and making it run, but was never convinced
> > it was 100% accurate.  It made heavy use of julian time, which with
> > the south american fellows trig libraries from the rainbow, seemed
> > to fall apart in March, 4714 BC IIRC.  I don't think julian time
> > likes itself when it goes below zero...
> 
> I have seen too many programs over the years that fail to take into
> consideration that on our calendar 1 BC (753 AUC) is the year before 1
> AD (754 AUC) and as a result are a year off for everything before 1
> AD. 
>   Of course you can easily start to get into all kinds of special
> problems as you go back especially as the Julian calendar only goes
> back to c. 700 AUC (c. 50 BC).
> 
> 
> -- 
> Coco mailing list
> Coco at maltedmedia.com
> http://five.pairlist.net/mailman/listinfo/coco