Important !!!

There is a FITS header bug in the MaxIm DL 6.21 release that may cause corrupted image data with some camera drivers.

If you upgrade to MaxIm DL 6.21 and you rely on time stamps for photometry series derived from the FITS header entry DATE-OBS or rely on ACP's True Focal Length, True Image Centre etc, FIT's header entries then check that the DATE-OBS is correctly added to the FITS header with your choice of camera driver.

It seems that MaxIm DL 6.21 handles the DATE-OBS header entry differently for some ASCOM drivers against direct plug-in drivers.

I have lost four nights worth of photometry data this week, over three hundred images, after upgrading MaxIm DL to version 6.21 last weekend and had not noticed that the FITS header entry for DATE-OBS was corrupted, or that ACP was reporting errors with each image taken, my bad for not looking at the ACP logs until today.

I have uninstalled MaxIm DL 6.21 and reinstalled version 6.20 and have confirmed with a ACP run using simulators that the bug is not present in version 6.20.

Screen-shot images below show the FITS header and ACP Console results with simulators for MaxIm DL 6.20 and 6.21.

I was going to post this on the Diffraction Limited forum but I see another user has done that already however I think this is also worth posting here.

Bob, you might think this is worth an alert to save users from unexpected problems when they process their data after upgrading to MaxIm DL 6.21.

MaxIm DL 6.20 FITS header OK, ACP OK.

MaxIm 6_20 Fits Header ok.jpg

MaxIm DL 6.21 FITS header not ok, ACP not OK.

MaxIm 6_21 Fits header error.jpg