Description

This image was obtained with a Canon 7D Mark II 20-megapixel digital camera and 300 mm

f/2.8 L IS II lens plus a 1.4x teleconverter giving 420 mm at f/4 and ISO 1600. No dark frame

subtraction, no flat fields. Tracking with an Astrotrac and no guiding. The 57 minutes total

exposure (57 1-minute exposures).

Modern DSLRs like the 7D Mark II include on sensor dark current suppression and low fixed pattern

noise at ISOs around 1600 and higher, making no need for dark frame subtraction. Modern raw

converters correct for light fall-off and also correct for hot/dead/stuck pixels. This makes

processing low light images easy: simply align and average.

More information on the image and my methods are here:

http://www.clarkvision.com/galleries/gallery.astrophoto-1/web/m33.c08.13.2015.0J6A5389-445-57frames-e-1200vs.html

