Topics

CCD Inspector Image / Flat Frame Analysis of AP130GTX + Quad TCC


johnrogerjennings@...
 

I've attached a CCD Inspector flat field image / analysis of my master flat. Without going into the details of the image train except the camera is a full frame QHY410C, is the attached result typical of this combination? (Ignore the camera over scan issue at the top of the frame) I've seen posts that indicated there is some residual vignetting in the corners this optical configuration. I.e.; Should I expect a reasonably (2-3%) flat frame all the way to the sensor diagonal edges (43.26mm) with only the AP130GTX and the Quad TCC and no other image train elements?

Does anyone have a CCD Inspector image / analysis of their system they are willing to share? Otherwise it could be subjective...


johnrogerjennings@...
 

Someone has pointed out to me the Cosine 4th law that describes diminished illumination across the image plane independent of vignetting.  Attached is a single flat frame from the same optical system with my QHY268C camera (APS-C sensor)  that is not vignetted due to any obstruction. It appears the same Cosine 4th illumination drop off can be seen starting at the center of the image. The only difference is the size of the sensor and total off axis distance.