Hello,
this night I did some tests with my image train. To do this I spotted on NGC891 with my C9+Reducer (f=1485mm).

The first plate solving worked very well, NGC891 was centered in the picture. I took some photos (approx 2 hours) and then did an autofocus. After that I did another platesolving. BUT: the coordinates had changed!!! I realized that after watching the first picture after that plate solving, the galaxy was not centered...

 

To solve this issue I had to go to kstars and klick on NGC891 - Details - Center in Telescope. After doing so, the plate solving used the right coordinates and centerd the galaxy. I had this problem already rarely in the past. What is wrong???

CS

Juergen

Nobody an idea why the coordinates of NGC891 where changed from RA02:23:57 DEC42:26:45 to RA02:22:57 DEC42:30:17?

Platesolvenig just show any close object. I think your scope just drifted away for some reason.

Plate solving should center the object I want. I want to center NGC891 (=PGC9031). Until line 3 NGC891 has the coordinates RA02:23:57 DEC42:26:45. In line 4 they changed to RA02:22:57 DEC42:30:17.

I dont think that NGC891 jumped to the new coordinates...

If you look on the delta in line 4 you see that the NGC891 was already nearly centered before. So why are the coordinates changed for NGC891????

That are solved coordinates of frame center. Last two columns is how far off target you are. On fourth line it is 17' off. So that is when you needed to recenter?

The first two rows are the RA/DEC coordinates of the target. The last two rows are the values how far I'm off the target. The first two rows should not change when I dont change the target. If you look at the first three lines: the RA/DEC rows dont change since I dont changed the target. The plate solving was succesfull. In the fourth line the RA/DEC changed but I dont changed the target. It is still PGC9031, as you can see in row number three.

If the coordinates in the first two rows were frame center coordinates they would have changed in the first three lines (and also form line four to line five), but they didnt. So these are target coordinates.

Juergen,

I believe I understand what could cause the plate solving target to drift several arc-minutes in a few hours. I agree it is not the desired behavior. Wolfgang, Jasem and I have discussed it, and the two of them are discussing how to correct the issue.

Hy

HI Hi

Did you ever figure out what would cause the RA and DEC coordinates to change - I am having a similar issue

Best

Mike

Hi Mike,
as far as I can say and understood the issue, it was a "bug" in kstars. It should be solved since version 3.5.6. Due to continuousliy bad weather I couldnt check it till now

What version of kstars do you use?

Best regards


Jürgen