[Slawomir (Suavi)]

Hi Andrew,

I have noticed two things that I will try to comment on.

1. You have pixel size set to 1micron for the Meade camera. From memory it should be about 8microns, thus guiding errors represented on this graph are really eight times larger. That will make both graphs comparable, but does not explain elongated stars with SSAG.

2. SNR for the star you have been guiding on with SSAG is way too small IMO. I'm getting over 100 to close to 200 with my autoguider. You either need to make your guiding exposures longer or find a brighter star or improve focus. From my experience with SSAG, 1 second might not be enough and seeing will cause your graph to go all over the place. Gradually try longer exposures until the blue graph stops alternating from exposure to exposure and you start getting consecutive corrections in the same direction. Then you can tweak aggressiveness, min movement etc to fine tune it. And since seeing varies even during one night, sometimes 1s guiding exposures will be fine, while other times you will need longer (2-4 second) guiding exposures. I would suggest trying 2s exposures and go from there.

Unfortunately HEQ5 may give less round stars with longer autoguiding exposures, but apart from fine tuning it mechanically there is not much more that can be done about it.

One more thing, those occasional spikes in Dec (red graph) will definitely spoil data - I think they highlight a mechanical / flex problem.

Please keep us informed.

Suavi