Why does the image appear dim compared to other cameras?

Altair cameras do not scale up to 16bit output automatically for consistency reasons, but some cameras do. This can appear as if the camera is not sensitive compared to other cameras. The same amount of data is there, however. To see the detail, the image needs to be “stretched”. If not stretched, this can cause problems with star detection and stacking in software which relies on intensity to identify star shapes. There’s usually a setting in your processing software to auto scale the camera output to 16bits, which will make it appear brighter, or you can just apply a manual stretch in post processing. There is also usually an option in the capture software to make your image appear brighter on the screen for focusing and framing, often this is called “screen stretch”. Another cause of a dim image can be if 8bit mode is selected when capturing the image, instead of 12bit or higher bit depth, depending on what you camera ADC supports. You can check your .FITS file to determine whether you may have used 8bit mode inadvertently. Here is a YouTube video about stretching deepsky images. (Opens new window).