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Old 09-11-2015, 06:05 PM
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Paul Haese
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Join Date: Jan 2009
Location: Adelaide
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A comparison between an AO and without

Whilst working on this project I thought it might be interesting to compare the set I started with last year and the set from this year. Since installing the AOX to my SBIG STXL11002 camera I have noted several completed images have shown distinctly sharper detail from traditionally guided data. Well at least I think it is distinctly sharper. It's not so much the larger detail components, it's the fine detail components that look sharper to me.

I have used identical processing techniques on both sets of data and it should be noted that one set contains 4.5 hours of data and the other contains 2 hours of data. Seeing was also very similar on both sets. The traditional guided images contains images which range from 2.45 -2.63" (4 in all) FWHM. With most being around 2.52". The AOX guided set contains FWHM values from 1.89 to 2.32" (9 in all) with most being around 2.11". I measured the values using CCDinspector. Now that might not seem like much but overall it seems to have an impact to the look to the image. The AOX set was hampered by high cloud in several subs. I have been imaging at 0.2 seconds with the AOX which equates to 3.6hz. It can image far faster rates but guide stars are hard to find which allow that.

I guess the point I am trying to make here is that even at modest guide rates the detail is sharper than traditional guiding. I don't think the AO works well in poor seeing though and that would seem to indicate that it does not cheat the seeing, so you need good seeing to get the best out of it. I don't know if it is purely eliminating mount related defects either. It just allows faster guiding without making many mount guide corrections (or at any rate far fewer).

Sorry about the different orientations, but this one of the downsides to using an AO.

Click here for image without AOX

Click here for image with AOX

Feel free to discuss. For me I have vindicated the cost outlay I made for the unit, but is it really difference worth that much in the minds of others?
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