Author Topic: Problem observing Tiangong 1  (Read 5419 times)

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Offline Barry Brown

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Problem observing Tiangong 1
« on: July 09, 2014, 08:28:18 PM »
I'm a new Sat Tracker user. I tried to observe Tiangong-1 last night, but ran into difficulties. This was my first time attempting on that particular satellite. The heavens-above website said there would be bright overhead pass around 9:30pm.

I downloaded the "Human Spaceflight" TLE from the space-track website and loaded it into Satellite Tracker. Then I did a batch predict, but it did not come up with anything. I unchecked all the filter options, but still nothing.

Clicking on the World Map showed the satellite bizarrely hovering over the north pole--or so it seemed as a novice user.

I verified that the TLE file contained lines for 37820, the ID for Tiangong-1.

I am able to successfully use Batch Predict for satellites from the "Visible" TLE file, so at least I know the app is working well.

What could I be doing wrong?

Offline John Eccles

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Re: Problem observing Tiangong 1
« Reply #1 on: July 09, 2014, 10:55:04 PM »
You probably already know this but I will say this anyway just in case:

1.  Make sure your location is correct and accurate in the Satellite Tracker application.
2.  Make sure you date and time is accurate in the Satellite Tracker application.
3.  Make sure that the orbital elements file is up to date and you have selected that up to date file.
4.  Make sure that what you are seeing on heavens-above for that particular satellite has the correct location, date and time for you viewing position.

Other than that maybe someone else can chime in on this one. I do not have a setup up and running yet so I can't help you with that.

Also, please let me know if any of these things caused your problem and, if not, and you have solved your problem please publish your results here.

John Eccles
« Last Edit: July 09, 2014, 10:56:37 PM by John Eccles »
Regards, John Eccles, Owner of Satellite Tracker Application, the Satellite Tracker Forum, and the Yahoo Groups called Satellite Tracker

Offline Barry Brown

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Re: Problem observing Tiangong 1
« Reply #2 on: July 09, 2014, 11:44:07 PM »
You probably already know this but I will say this anyway just in case:

1.  Make sure your location is correct and accurate in the Satellite Tracker application.
2.  Make sure you date and time is accurate in the Satellite Tracker application.
3.  Make sure that the orbital elements file is up to date and you have selected that up to date file.
4.  Make sure that what you are seeing on heavens-above for that particular satellite has the correct location, date and time for you viewing position.

Other than that maybe someone else can chime in on this one. I do not have a setup up and running yet so I can't help you with that.

Also, please let me know if any of these things caused your problem and, if not, and you have solved your problem please publish your results here.

1. Yes. I am able to track satellites in the "visual.txt" TLE file. The scope is spot-on when the satellite appears.

2. Same.

3. I'm downloading from the "Recent TLEs" -> "Current Catalog Files" page.

4. Yes. At the appointed time, the satellite appeared over my head and arced across the sky. Wasn't able to follow it with the scope, though.

Here is the TLE file I downloaded.

1 25544U 98067A   14189.90173361  .00010607  00000-0  19028-3 0  6627
2 25544 051.6477 351.9236 0003462 223.5395 293.6531 15.50490712894694
1 37820U 11053A   14189.88815728  .00045776  00000-0  30233-3 0  1850
2 37820 042.7706 180.3214 0012659 156.1986 282.0516 15.74705272159465

Load it up in Sat Tracker and plot it on the world map. You'll see that it's sitting above the north pole.

Offline Barry Brown

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Re: Problem observing Tiangong 1
« Reply #3 on: July 09, 2014, 11:53:02 PM »
Another oddity:

When you open up the TLE file, the "ISS Monitor" sidebar goes wonky. Most of the fields get zeroed out and the map becomes blank.

Perhaps there is something peculiar about that specific TLE file that Sat Tracker can't handle.

Offline John Eccles

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Re: Problem observing Tiangong 1
« Reply #4 on: July 10, 2014, 07:53:01 AM »
From jimmyjujames with post on the Yahoo Group:

Satellite Tracker requires a 3 line TLE
Line 0 can be up to 24 characters long.
Changed your 2-line tle to 3-line tle and working as advertised.

1 25544U 98067A   14189.90173361  .00010607  00000-0  19028-3 0  6627
2 25544 051.6477 351.9236 0003462 223.5395 293.6531 15.50490712894694
1 37820U 11053A   14189.88815728  .00045776  00000-0  30233-3 0  1850
2 37820 042.7706 180.3214 0012659 156.1986 282.0516 15.74705272159465

ISS
1 25544U 98067A   14189.90173361  .00010607  00000-0  19028-3 0  6627
2 25544 051.6477 351.9236 0003462 223.5395 293.6531 15.50490712894694
Tiangong-1
1 37820U 11053A   14189.88815728  .00045776  00000-0  30233-3 0  1850
2 37820 042.7706 180.3214 0012659 156.1986 282.0516 15.74705272159465

Jimmy
Regards, John Eccles, Owner of Satellite Tracker Application, the Satellite Tracker Forum, and the Yahoo Groups called Satellite Tracker

Offline Barry Brown

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Re: Problem observing Tiangong 1
« Reply #5 on: July 11, 2014, 06:16:12 PM »
Thanks! That worked.

The reason I downloaded the 2-line files is that's what the application's help file suggested. I understand now that TLE stands for "two line element", but there are 3-line and 2-line versions.

I think that in the next version of Sat Tracker, it either ought to warn that 2-line files are not compatible or it should allow 2-line files.

Anyway, thanks again. Now I can go set up the scope to look for the satellite tonight.

Offline John Eccles

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Re: Problem observing Tiangong 1
« Reply #6 on: July 11, 2014, 10:10:12 PM »
I will check on this and make the necessary corrections. Sorry about the confusion.

John
Regards, John Eccles, Owner of Satellite Tracker Application, the Satellite Tracker Forum, and the Yahoo Groups called Satellite Tracker