T-Point troubles

[gregbradley]

Just 6 weeks ago I did a successful 300+ point Tpoint model.

Now it won't plate solve saying check the RA and Dec of the files. This is with the Sky X and a quite recent (6 week old or so) build.

I don't enter the RA and Dec as it picks it up automatically. They appear to be correct. I have the images on auto save.

The only change is the scope from an AP140 to the AP RHA.

If I click on astrometric solve it plates solve then. But I am trying to do a recalibration of a T-point model.

Greg.

[cfranks (Charles)]

I believe that changing your OTA will negate your previous TPoint run and requires you to do a new 'Full' calibration. I don't know the parameters of your telescope(s) but I would suspect the 'arcseconds per pixel' parameter has changed.

Charles

[gregbradley]

Thanks Charles. Yes I did enter the new arc seconds per pixel numbers and I can plate solve manually in CCDSoft and also from a photo in Sky X.

A new model would be needed as I am sure the dynamics are quite different now with the new scope being a lot heavier than the last ones I used.

For some reason it is giving me this error to check RA DEC values in the file and it could not find a match.

I am confident the image scale is correct and even the north angle is correct.

At one stage I did get an error saying I needed to reload the sky database.

Perhaps I should do that. There is an option in one menu to do that.

I should check for any software updates on Sky X and TPoint.

Greg.

[cfranks (Charles)]

Hi Greg, that error message also says 'double check the image scale'. Check your binning too. I think it uses the value in the Telescope/TPoint Add On Settings/Automated Calibration/Setup/Image Scale. I usually guess and then press 'Take and Image Link photo 'button'. If that is successful, it gives you the correct value and the PA. Image Link Blind solve can be useful too, if you are not too far out. That Image Link All Sky search is magic!
Good luck.
Charles

[rally]

Greg,

I'm not sure what Tpoint parameters your model is using but, but Tpoint in Auto mode considers a heap of parameters - many of which are completely dependent (and exclusive) to the particular type of scope you have as well as the specific scope as its installed at that time.
ie some parameters only apply to mirrors and not refractors, so if they are missing or are not being using or different then its not likely to be working very well.

In your case you have switched between a refractor and a mirror, with probably different mounting systems.

There is little chance that one Tpoint model will work properly with another type of scope and even the removal and reattachment of the same scope could potentially mess things up.
Especially if there is any offset with the physical and optical axis, mirror flop etc

Just redo a new model.

Rally

[jase (Jason)]

Yep, scope change = new model. Don't stuff around with recalibration.