[Kstars-devel] [ask]Little features, with ISS and transits...

[Jason Harris]

Hi JB,

Sounds very interesting, I'd welcome such a feature in KStars.  We have had 
several inquiries about such a feature (just had one yesterday, in fact).  
However, I was always reluctant because I feared the CPU burden of having 
Earth satellites zooming by overhead in real-time.

However, on reading your suggestion, I realize that we wouldn't need to do it 
that way.  As you say, we can simply draw the curve of the satellites track, 
which would be static on the sky.  You could even add tickmarks and labels 
showing the time at which the satellite passed.  I think that would be great!  

We don't really have a plugin architecture; I suggest we add satellite tracks 
as a new class of objects drawn on the skymap.  How many satellites are you 
thinking of including?  Presumably, we will add a page to the configuration 
window that allows the user to select which satellite tracks are shown.

So, to get started, I guess we need a SatelliteTrack class that contains 
the satellite's TLE data, and a QValueList<SkyPoint> containing the track 
across the sky.  It should also have a QValueList<QTime> containing the time 
at each position along the track.  It will also need methods to determine if 
it is visible on a given night, at a given location; and to compute the track 
for a given night, at a given location.  Once this is in place, we can start 
integrating it into the rest of the code (Skymap, Options dialog, KStarsData 
for reading in data files and updating the tracks, Whats Up Tonight for 
predicting satellite passages, etc).

As for the accuracy of our Sun and Moon positions, they are pretty good.  
KStars does a good job of reproducing solar eclipses.

Other thoughts?

Jason

On Thursday 09 June 2005 01:24 pm, jb wrote:
> Hi all :)
>
> We're currently working on a fork of  "predict", a software that can
> compute stallites trajectory, aiming that we could compute ISS transits on
> SUN and MOON.
> But, we have pbs, because accuracy of Sun trajectory and moon tajetory are
> bad. (and we are poor programmers ...)
>
> So, as Kstars have (I think) a good accuracy for Sun and Moon position, i
> wonder if we could add a plugin (or other ways) to compute ISS (or other
> satellites) trajectory with TLE's. (Three Line Elements, Keplerian elements
> of orbit)
>
> Clear skies,
>
>     JB BUTET, Lin4astro
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KStars: KDE Desktop Planetarium
http://edu.kde.org/kstars