First of all hello everyone, I am a newcomer both to the forums and have owned PI for abt 3 months. I am very pleased of the sofware and very eager to learn to use it.
I am a DSLR user (D7100) but am unaware of the details how the camera sensors work, ie how the picture is affected by different things in the macro level. So basicly I am very noob on that sense, so learning is almost 100 pct of following the tutorial examples and seeing what happens, then altering the parameters a bit and seeing again the difference. And although I can English pretty well the technical camera vocabularity is not that clear.
Before my first question this is a direct quote from PI main site on 'Master Calibration Frames: Acquisition and Processing' by Mr. Vicent Peris:
++++
IC is optimized to work with calibration libraries: don't worry about differing temperatures and exposure times between dark and light frames. IC will always rescale the dark noise to match every light frame.
It is also very important to have a bias library, because thermal noise must be bias-subtracted: only thermal noise must be rescaled in the master dark to match the thermal noise in the light frame.
After experimentation, I highly recommend taking at least 10 dark and bias frames. Never use less bias than dark frames, because this would introduce too much read noise in the bias-subtracted master dark: a 50-frame master dark will have almost all the read noise of a 10-frame master bias.
++++
Ok, I also just learned about making the super BIAS, and tested it also with one of my Master BIAS which was created from my abt 40 BIAS frames. The outcome was very smooth. But as the SUPER BIAS description tells me the program does something to the master BIAS so that it multiplies the Master by tens or even hundreds making it an equivalent of, let's say a couple of thousand individual BIAS frames. At least if there are the 200 BIAS frames to start with.
The thing that puzzles me is that as on the Mr. Peris tutorial he says that 'never use less BIAS than Darks'. I usually take 30 darks frames from each session. They are always the same length as my light frames and temperature is also quite close to the actual temp wich was outside as I start taking those outside when unriggin my gear.
Another thing I noticed now then is that PI is advanced software so it can scale the darks and that libraries are used. So basicly as I have gathered from all my sessions propably abt a few hundred darks during this year could I just use them now? But it would still be less than with the super BIAS.
I have not taken flats so far.
Here to recap my questions:
aa) The number of BIAS (using the super BIAS) vs the number of DARKs?
bb) How much does the noise differ on the same camera sensor with time?. (Ie could I just make a one Master Dark for each ISO setting I use out of for example thousand DARK frames of 10 sec exposure each taken indoors and use that always).
cc) Same as bb but with BIAS.
Thanks,
Arnie
