Hi, I'm entertaining the idea of a new camera and have a couple of questions about the StackPro feature and how it relates to binning the data. First, my assumptions/understanding on how StackPro works. The AC2020BSI has a 12-bit A/D converter - so images taken have essentially 4096 values. Using StackPro, the camera will take 16 individual images - all at 12-bits. My understanding is that the in camera stacking is a straight summing of the data of all 16 images - so if a pixel in has a value of 2000 ADU in each image, the resulting image will have a value of 32,000 ADU for that pixel. The end result is that StackPro creates a true 16-bit image coming out of the camera with that summing. So that brings me to two questions as I consider how I'll use this camera if/when I obtain one. My plan is for *some* astrophotography, but mostly photometry. What happens in terms of binning the camera 2x2 and using StackPro? With a longer focal length scope I'd need to bin the data to get around the 1.5"/pixel that'd be ideal for photometry in my typical seeing conditions. If I have four pixels that have a value of 32000 ADU after stacking 16 frames in camera, the binned pixel will have a value of 128,000 ADU after binning - so it'll come out with a value of 65,535 - and clip the data. Is the data just clipped then, or is there something in this scenario that would preserve the dynamic range gains of StackPro? Is StackPro controlled specifically in MaximDL or the camera driver? I'm using a Paramount mount, so there's value in using TheSkyX for all of the telescope control. Is StackPro operable from TheSkyX or do I need to be using MaximDL? I haven't determined which software I'll use to control the telescope/camera at this point. I'm familar with both.....just planning my usage. Thanks, Mike
The GSENSE2020BSI sensor does not have built-in binning capability. Binning is performed in the driver after image download. It averages the four pixels so the dynamic range is preserved - it does not clip the data. StackPro is controlled by the camera. There is a setting to specify your target subexposure length, and the camera automatically optimizes the number of subexposures it takes to try and get as close to that as possible. That allows you to adjust the exposure length as you need without having to worry about constantly tweaking the StackPro settings. When using TheSky, the target subexposure duration would be set in the ASCOM driver. A complete description of the StackPro behavior is included in the user manual. https://diffractionlimited.com/downloads/SBIG_Aluma_AC_Series_Users_Manual.pdf Here is the relevant excerpt: Typical values for the Subexposure duration would be in the 10 to 30 second range.
Thanks for the quick response Doug, This is encouraging. I was making an assumption that all binning is/was additive and thought that it meant that StackPro and Binning were mutually exclusive things. I'm very happy to see that they're not. Thanks, Mike
