I have recently started using an ASI 183MM Pro CMOS camera for photometry. I started off using the ZWO ASIIMG software for image capture. However on checking the times recorded in the DATE-OBS field of the FITS header, as far as I can see, these record the end time of the exposure when they should record the start. If anyone is using this software, it might be worth checking that the information in the DATE-OBS field is what they are expecting it to be. I have now switched to SIPS which seems to be fine.