Re: potential visibility utility

Leo Barhorst (
Tue, 21 Jul 1998 12:41:42 +0000

Walter Nissen wrote:

> If elsets from OIG are going to be at a premium, has anyone thought of 
> writing a utility which would go thru a file of elsets and divide it, or 
> at least the catalog numbers, into 2 sets: 
> a) those whose orbits will be illuminated in the dark above a given site 
> during a given period, i.e., those which are potentially observable if the 
> drag produces a suitable mean anomaly            --and-- 
> b) those which definitely won't be visible. 
> With a utility like this, people wouldn't have to waste requests for 
> elsets of objects they won't see anyway. 

In Patrick Will's SAT 4.75, the old DOS prediction program of the 
Belgian Working Group, this feature is available.
In the Various Calqulations you can plot per satellite the visibility 
periods for your observation place for one year. It is shown in a 
graphical form.

> 'Course, this wouldn't be absolutely perfect.  E.g., you'd still have to 
> include such as shuttles and decayers which might be self-luminous. 

This is true for one place. But what about the differance between US 
and Europe or southern hemisphere?
A satellite not visible for the US can be perfectly visible in Europe 
or Australia.
So we'll need TLE's of all satellites in order to keep everybody 

Leo Barhorst