Equipment compatibility - Forums

Topic starter

Apr 16, 2021

Posted a question yesterday but the post disappeared never showed up. I'll try again;

I was using my Celestron 1100HD and Starlight Xpress Trius 814 OSC with the Celestron .7 focal reducer. I was unable to perform an automated TPoint run using TheSkyX pro and my Software Bisque Paramount MX+. Kept getting the error message: not enough stars to perform an image link. Tried a manual calibration run with only 12 stars scattered across both sides of the meridan. Was able to obtain an excellent polar alignment. However, pointing accuracy was horrible. Mount would not place target on chip. Could it be that my OTA/camera combination is incompatible? The 814's sensor is fairly small at 3388 x 2712 pixels with a pixel size of 3.69. Anyone with similar experiences please chime in with any feedback or any techniques on performing a calibration run with this combination. I might have to change it up.

Patrick G.

Helpful Engaging

Tim Hutchison

Apr 17, 2021

Hi Patrick.

With this setup you are at 0.39"/pixel (unless I got something wrong). That is severely oversampled. I typically try to stay between 0.7 - 2.0"/pixel.

The oversampling may be making it difficult to plate solve your images. You may want to consider binning, if that is an option with that camera. I am not familiar with that camera but typically there is a software setting that will allow you to bin. With your focal reducer, binning 2x2 will get you over 0.7 which should work. If you can do it, it's a quick, cheap test. If you can't, try to take an image and see if you can solve it with another plate solver like PlateSolve2 from PlaneWave or ASTAP (both free) or upload to nova.astronomy.net just to see what happens. It will be good information if you are forced to talk to the folks at Bisque to try and debug.

Hope that helps.
Tim

Well Written Helpful Insightful Supportive

Patrick Graham

Topic starter

Apr 17, 2021

Tim,

Sounds like you're correct. I didn't consider the oversampling consequence. I don't have that issue with my triple APO refractor and that same camera. The TPoint runs flawlessly and puts the target dead center on the sensor. I'll try the binning at 2x2. I should have thought of that before so thanks for the suggestions.

Pat