[amsat-bb] Orbitron Help

[GARY ELLIOT]

Morning to the Group,

I am a "newbie" as far as satellites go and having some problems with Orbitron as my tracking software. I realize that the software offered my AMSAT SATpc32 certainly looks like the one to go with or Nova but at this stage of my venture into satellites I wanted to stick with a free piece of software. That being said, here is the problem I am having.

First off my computer is fairly new running XP and 1GB of RAM and my clock is right on with WWV

I have updated Orbitron with the latest TLE's or Keps so they are current

Now when I run predications on Orbitron 3.71 and compare them with the pass predications on the AMSAT web page they are really different ???? not even close, yet when I look at the actual real time position of a satellite say AO51 on both the AMSAT page and my Orbitron they are very very close, in fact look the same to me by eye.

So why are the pass predications so off from each other ????? I assume it must be in my setup in Orbitron but have gone over these several times. I had a VE2 gentlemen who was running Orbitron trying to help me but when he runs his pass predications and compares them to the AMSAT pass predications they are the same ?

Obviously I have something wrong so not sure where to go here, delete Orbitron and start with another download and try again ? that does not seem to likely to be the answer to me ? I also took a look at SATscape as a tracking problem but that seem rather confusing so gave up on that one as could not get it to run right either.

So I am open to some suggestions/advice on Orbitron or any other free tracking software to try and then compare to the AMSAT page to make sure they are the same as far as predications.

73 Gary

[Alan P. Biddle]

Gary,

Is the difference in pass prediction times by any chance the difference
between your local time and UTC? Since the real time data is correct, you
have the QTH and keps correct. I am not familiar with Orbitron, but most
programs give you the choice of display in local or UTC.

Alan
WA4SCA

[Franklin Antonio]

Post by GARY ELLIOT
when I look at the actual real time position of a satellite say AO51
on both the AMSAT page and my Orbitron they are very very close, in
fact look the same to me by eye.
So why are the pass predications so off from each other ?????

If the satellite position is same in the two predictions, but the
azimuth and elevation are different, then the difference must be in
the position of YOUR STATION. Perhaps you have entered the station
position incorrectly? I'm not familiar with Orbitron, but a common
problem with many programs is confusing east longitude with west longitude.

On the other hand, when you say "they look the same by eye", that may
not be the best comparison method. How accurately have you set your
PC's clock? Low orbiting satellites move over your station quite
quickly. You want time to be set within a few seconds of the correct
value. You don't want to be a few minutes off.

[Tim Tuck]

Hi Gary,

One thing you might like to check, that is really easy to overlook, is the Time
Zone of your computer. If thats not set correctly your predictions will be off.

cheers

Tim