It's all about the Software

I notice that there is a 5-6 minute difference in the ISS AOS/LOS times between satellite tracker in SDRC versus the prediction in PstRotator. Both applications have the exact Lon/Lat . Any ideas on how to resolve this? As far as I can tell, the keps are updated for both applications. I'm not sure which one is "incorrect". For example, the next ISS path is listed in PstRotator as AOS 00:05UTC whereas SDR has the next pass at 00:11 . Other satellites/ships seem to be more accurate.


Andy K3UK

Andy,

I see absolutely no usable info here, for example screenshots. I can't help you based on the lack of info .

Which one agrees with Heavens-above.com? They are usually VERY accurate with their plots for the ISS as well as other orbiting objects.

For example, my location:
https://www.heavens-above.com/PassSumma ... t=0&tz=EST

They did get a little boost in their orbital altitude when the Space-X Crew 1 arrived last week. That's all it take to throw off the times a few minutes.
So possibly a change in the Keps?

73 Kriss KA1GJU

Also,

You must ensure you have the latest TLE data. AMSAT US's data sets are often out of date, there was a recent docking which always nudges the ISS hence get the latest TLE, I suggest Celestrak.

My software takes TLE data from many files and uses the most recent TLE data.

The attachment shows the PstRotator on the left and SDRC on the right. Note the LOS/AOS time difference.
I'll check the source for the keps.

Andy

Kriss, I am not sure how Heavens Above's listed times differ based on my actual location as I see no place on their site to provide my coordinates. However, they cite AOS of 17:40 today. SDRC cites 17:36 and PstRotator cites 17:43

Andy.

k3uk wrote: ↑Sun Nov 29, 2020 11:18 am The passpicture.jpg attachment shows the PstRotator on the left and SDRC on the right. Note the LOS/AOS time difference.
I'll check the source for the keps.

Andy

No No No!

For goodness' sake take a proper screenshot and look at the data. A pic with a GSM is a total waste of time.

Andy, go to the home page of Heavens-Above, and check out Configuration.
You can directly enter coordinates or us the map and click on your location (be sure to zoom in once in the general area).
Also make sure the proper time zone and offset are good.
You don't have to be a member, i.e. sign up. It will remember your location until changed.

73 Kriss KA1GJU

IMO the only reason for difference between two programs known to be good is different date of TLE. The date is actually in the TLE data.

Simon, as you know I have been a long time supporter of your software. Going back to the early days of HRD, moderating a section in the old HRD forum, still moderating the GroupsIo SDRC group, and a member of the test teams going back to beta testing of DM780 . Until my retirement, I was a regular contributor to your "dog food campaign". I have been increasingly weary of your browbeating and worsening intolerance towards those asking questions. My profession has been one of helping others and thus demonstrating a willingness to be patient with some seemingly unnecessary requests for help. A key element of customer service is not "scolding" people like a baby .
Thus, I will today end this relationship, remove myself from the moderating duties at the Groupsio site and switch to other SDR software.

Andy K3UK