New user question guiding

Hi everyone

Just started to try this software out over last few days - and very impresssed! I have read through the copious and very good documentation (have tried to absorb it all!) and managed to successfully work with the simulators. Made good progress last night working with the real sky and got very close to a successful 1st auto image. Where I hit a problem was in the autoguiding area, specifically the A0-7 that I have used for a number of years. I had calibrated the autoguider and for me the x-axis calibration was checked in Maxim - and it successfully nudged the star when it wandered too far when guiding withn Maxim only. But within ACP I found that the x-axis calibration was checkbox unchecked right at the point of ACP doing a guide - I wasnt expecting this so checked it several times and this is indeed happening. So rather that a nudge recentering a star it is moving it away from the field of view when guiding. I did wonder if I needed to change the sensor orientation PA - so retried at 90, 180 and 270 degrees but all gave the same problem. At that point i ran out of ideas! I see previous posts having similar problems but cant see if/how it was resolved.

I am sure you may need additional information to help me but wanted to keep the initial question short just incase there is an obvious answer.

Cheers, Alan

Alan --

1. Are you using a rotator?
2. Is this an off-axis pickoff or an internal guide chip (SBIG)?

ACP does not require you to calibrate the AP-7 Drive, only the AO-7 AO must be calibrated (which I am sure yours is). The key things are, under settings, the Reverse X, Reverse Y and Swap Axes settings, and ACP manages them. For the gory details see my engineering paper Rotated Guiding of Astronomical Telescopes.

Once I know the answers to the above 2 questions I may be able to help further.

Hi Bob

thanks for your reply and super quick response. In answer to your questions

- no rotator - it's on the shopping list but haven't gotten there yet
- it's an internal sbig guide chip

yes the ao-7 is calibrated. I did read that ACP doesn't need anything else which was my understanding which is why I assumed it unsets everything in the guide calibration. And that is the dilemma for me as can't think of anything I can set/unset

let me know what you think and can try

Kind regards Alan

Then set it to External Guidescope and check the adaptive optics checkbox. Then calibrate the drive looking east. I know it's confusing but even with no rotator, by request it assumes that you are rotating manually if you select Internal or Off-Axis. If you aren't then it needs to treat it as an external guidescope. I'm not sure this will work though... I am not 100% sure I tested it.

Ok will give it a go next clear night - hope I can get this to work. Do I assume that this new approach uses the guider calibration results from Maxim?

Btw I notice reading back that previous users have experienced similar problems and managed to get it working on previous releases. Has the code in this area changed a lot since then

thanks Alan

The AO calibration from MaxIm is used. The Drive calibration from MaxIm would be used for your non-rotated configuration.

Hi Bob

no clear weather yet but just been checking the screens. Assume you mean I modify settings in ACPs preferences-guiding tabs? But if I set the sensor configuration. To "external guide scope" the ao check box is greyed out (though it remains ticked). Am I doing the right thing?

thanks Alan

Hi Bob

not great conditions tonight but good enough to allow me to try out what you suggested. As per earlier post I set guider to external in preferences which greyed out the ao7 check box that was already checked. Then calibrated which set my x-axis. Then tried test image and again at the same point ACP unsets the x-axis check box and my guide star is knocked out of the image when it tries to guide.

so do I conclude it doesn't work for my setup? I do read back 3 or so years ago someone got it working with similar equipment (ie no rotator and an ao7) but this was for an earlier release of ACP - don't want to keep investing time if it isn't going to work with my setup (which would be a pity as everything else seems to be working very well so far ).

cheers Alan

Alan, I apologize. I am at a conference and not in a position to do the detailed engineering analysis/review of my code. As I said at wasn't 100% sure I ever tried/tested AO with no rotator or no manual rotation. I'm going to say right now theta the configuration is not supported. I'm sorry!!!