Lodestar/MaxIm Guide Fade Fade Reprise 3

[Ronald Crouch]

Hello All,

Posting this on Maxim too. The problem: Super bright guide stars fail to be detected by Maxim.

OK. Hardware.. Lodestar 1 shot binned 2x2 as guider. Full calibration fresh darks.. In ACP a guider S/N of 12 was requested. I moved that up from 6 after guiding simply failed totally. A typical guide star box image has noise of 30 and the star at 23000 counts. SNR in Maxim aperture says > 90/1. Problem.. guide star fade over and over. If Maxim registers a "fade" during actual acquisition not a big problem cause tracking is superb.. My Mach 1 is < 1 arc-sec PE with the 120mm APO.. If fade prevents guiding from ever starting it can be a small problem for 180 sec subs but a big problem for 900 sec subs. The attached zip file is a directory which contains the ACP log, MaximLog, Tracking Log and another folder with all the guide star images over the same period which was about 3:56 til 4:56 UT.

My inspection of guide star images suggests they are undersampled being binned 2x2 which is about 2.1 arc-sec/pixel. Main OTA is at 1.5 or 1.75 arc-sec/pixel depending on reducer. It is a crazy sharp 120mm APO with the lodestar on the guide port of a QSI583wsg8. Guide chip/path look fairly free of dust and smudges.

Basically this long standing Maxim guide star fade problem means I cannot reliably use Maxim 6.13 which means I cannot use ACP or Focusmax 4. I can go back to Maxim 4.61 / Focusmax 3 and CCDA which does not have the problem. TheSkX/CCDA is also an option. Both TSX and PHD will guide forever and never fail to see the guide star. It seems a pity to have invested so much money in 3 software packages which have great promise but can be non-productive because a bright guide star cannot be be seen by one of the packages. I LOVE ACP and hate to have to give it up . Really great clear nights are precious and I simply cannot lose subs with a great setup for such a reason.

Any suggestions appreciated. Does anyone see something to try other than not binning the guider but I know others have tried that to no avail already. I sure wish ACP for just image production without an observatory could escape Maxim 6. Just sayin..

Best,
Ron