Problem with autoguiding MaximDL

[konstantinos75]

Hi

During a multiple nights CCD astrophotography I faced a problem with autoguiding. I used MaximDL to make the autoguiding over the ST4 port of my mount.

The first night all went successfully. I took 20x10min exposures in Ha. Dithering was set to be 3 pixels between the exposures. Then I parked the scope and did not dismantle it.

The second night, I configured MaximDL to capture 60x1min exposures in every filter R,G,B for the same target as first night. Dithering was set to be 2 pixels between the exposures. Autoguiding went wrong. My frames ended up with elongated stars. Then I parked the scope and did not dismantle it.

The third night, I configured MaximDL to capture 30x1min exposures in R filter for the same target as previous night. Dithering was set to be 2 pixels between the exposures. Autoguiding went again wrong. I received an error message from MaximDL that autoguiding went wrong.

I attach the tracking graphs for three nights plus the MaximDL track logs for nights 2,3.

Does anybody has an idea what went wrong with autoguiding the second and third night?

Thank you

Konstantinos

www.albireo.gr

P.S. the target was IC 1871 in Cassiopeia

autoguiding.zip

[swag72]

I know that you didn't dismantle anything - But did you recalibrate the guiding in between times? If I ever had any issue with guiding, then my first port of call would be to recalibrate.

[ollypenrice]

Also guider cables. These are very fussy, especially if you are using the original Lodestar.

Olly

[konstantinos75]

Hi 

I re calibrated between different nights and also cables were firmly connected.

[konstantinos75]

I did some research on this issue by studying better the MaximDL tracking graph.

I strongly believe that my problem was caused by the fluctuation in brightness of the guiding star in nights 2,3.

Maybe this was triggered by bad seeing, or some cloud in the upper layers of the atmosphere.

Have a look at the next attachments which prove my assumption of guide star issue.