I recently came across this informative and useful .pdf article by Jim McMillan regarding the many nuances of autoguiding. When the general literature gives the impression that it is a straightforward and relatively easy process it is reassuring to read Jim's article revealing that it is far from being so as I have spent the last year discovering. With the feedback I'm getting from Metaguide my last few sessions have clarified just how much the seeing affects autoguiding performance. I usually try and start imaging as soon as it gets dark but in reality this is often when the seeing is quite poor and it is only after a few hours that it might improve. Although an accuracy of around 2 arcseconds does seem possible under good conditions it is often 6 arcseconds or worse on some evenings.


caracol_uk said...

That's a very interesting document Pete. The methodical layout of the theory and subsequent analysis of the results achieved make it clear that the author spent much time analysing the information he obtained before reaching the recommendations.

I've filed this one away for future reference as I've not yet entered the world of autoguiding. However, that will hopefully change soon as I've recently ordered the Orion ST80 as my chosen guidescope. Ironically it's the same guidescope the author of this document is using. I was also a little surprised that the imaging scale he is using is well below 1 arc sec/pixel. I'd worked mine out to be about 0.83 arc sec/pixel and everything I have read so far suggests that is far too low. Apparently a good target to aim for is about 2-3 arc sex/pixel on the main imaging camera unless you have a superb mount and superb seeing in which case you might get away with 1 arc sec/pixel.

I'm quite looking forward to experimenting with autoguiding, and it certainly looks like the PEMPro graphing utility will come in handy to better understand what is actually going on.


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