I have run the specs for readout noise for my AC 455 with the firmware version 27 installed. I have included the test results below. The test was performed using MaximDL 7LT and the PixInsight script Instrumentation -> BasicCCDparameters. The test was performed with the camera cooled to 0 degrees C. The results are in the range expected for the IMX 455 chip, with the high gain noise being impressively low at 1.6 e-. I am still having some issues using the ASCOM drivers with TheSky. Everything works well at the high gain setting. However, if I try to change the setting to low gain, nothing happens, and the camera still reads out at high gain. If anyone has some relevant experience, please let me know. I will try using the thru-Maxim option in the camera setup in TheSky, and see how that works (I have been resisting because of my long experience with TheSky). High Gain Result Low Gain Result .
Great news - thanks for confirming. Hmmm.... I'm not sure exactly what you experienced. Did you change the ASCOM properties to Low Gain, with a Low Gain multiplier of 1.0? Looking at the data tables above, the gain change gave the expected different result (exactly 3.0). Was this data acquired through TheSky or MaxIm? Perhaps another user can chime in.
All of the data for the test I showed was collected using Maxim7 LT. When I use ASCOM through TheSky the gain does not appear to change no matter what setting I choose in the ASCOM camera setup window. The ASCOM setting window has two numeric fields for high and low gain. The numbers in the ASCOM setting window are 3.0 (high gain) and 1.0 (low gain). I do not change these. In this same setting window, there is a text field with three gain choices: Camera Default; High Gain; or Low Gain. I get the same data regardless of which choice I put in the text field. The results are the same as I would get using the high gain setting in Maxim 7LT.
I added these for clarity. The below images are from running ASCOM Diagnostics. The first image I was running diagnostics and pulled the camera properties. This is the same window I see when setting properties in TheSky. As stated in the above note, the Default Readout Mode text field allows three options: Camera Default; High Gain; and Low Gain. The next image down is described below. This below image is from the ASCOM diagnostics, where I connected to the camera and got the profile. Most of this has little meaning for me. I did notice that there are Gain Adjustment fields mentioned.
Vince, I can confirm that the ASCOM gain settings are not getting through to the underlying driver as expected; so it seems if you set the gain values in MaxIm, they will get used in ASCOM. This is not right. Our engineering folks will have to dig into this.
