Reply To: Bias Frames for CMOS

Forums Photometry Bias Frames for CMOS Reply To: Bias Frames for CMOS

Grant Privett

The paper:

is quite an interesting read. Looks like a reasonable number of noisier pixels on quite a popular camera.

AAVSO also have a report on the QHY600 camera from 2020 and S&T have a review of the QHY600 (De Cicco?) – where the bias issues were mentioned.

One thing to remember is that it comes in two flavours: research grade (best used with their fibre link) and the lower quality chip (mainly USB3) cameras.

I’ve been wondering how each pixel having its own read out noise characteristics works when stacking images using Medians or Sigma Clipping. My gut instinct says not quite as well, but I would recommend testing that in practice. I think it means dithering may have become an essential but the saved readout time over a night may balance out the need for more frames.

Might also try a defect map.

  • This reply was modified 7 months, 3 weeks ago by Grant Privett.