Shortest exposure to minimize "iris" effect?
Hi, I am commissioning a new Apogee Aspen CG16M Camera. I'm used to the SBIG type rotating shutter and not used to the Iris type shutter that the Apogee's have. I noticed that in short exposures its easy to see the opening/closing iris effect which I'm not used to seeing.
So, as a rull of thumb, how long to do you have to expose, both science images and flat fields, to reduce the effect so that it does not unduly affect your photometry?
--- Dave LDJ