Guide to Preprocessing of Raw Data with PixInsight

[cloudbait]

What I was trying to say is that, with the IMX571 sensor, calibrating flats with bias or with short exposure darks doesn't make any differences (or at least I couldn't see any in my tests)

As a bias frame is just a special case of a dark, where the exposure time is short enough that the dark current signal doesn't rise above the noise floor, it is worth testing any camera to determine what that maximum exposure is. The only time I've ever seen a controlled exposure dark be required for calibrating a flat is with some narrowband flats where the exposure time actually gets up to 10 seconds or more.

(I also think there are some special cases that involve sensors with significant amp glow, although I've never had to deal with that myself.)

 

[bulrichl]

The following changes were made today in my guide "Preprocessing of Raw Image Data with PixInsight":

• A reference is given for correct calculation of dark current even when /optical black level subtraction/ is applied in the camera.
• Information about the ASCOM platform, INDI and Indigo is moved into an endnote.
• The term "native camera driver" is replaced by "direct camera driver".
• Architectural and performance differences between direct and ASCOM camera drivers are described.
• Streaming data (video) mode and single exposure (still) mode are mentioned.
• The section about metadata in proprietary raw file formats is enhanced.
• WBPP: input of missing metadata required for computing astrometric solutions is described.
• The recommended Debayering method for astronomical images is VNG.
• Some wrong cross references within this guide are corrected.
• Several references are complemented.

Bernd

 

[bulrichl]

The following changes were made today in my guide "Preprocessing of Raw Image Data with PixInsight":

• Sections A3.2 "Metadata required for correct image calibration" and A3.3 "Metadata required for exact computing of astrometric solutions" are revised. Passages about WBPP are transferred into chapter D.
• Section C2 "Cosmetic Correction" is complemented by recommendations for the correction of images of OSC cameras
• Section C4 "Blink Tool, Subframe Weighting" is revised.
• The chapter about WBPP is rewritten. It now contains an outline about WBPP's development, structure and elements of WBPP's user interface, and WBPP's mode of operation.

The PDF file is now compressed in order to enable upload to this forum.

Bernd