Incredible dark, transparent skies here last night! So I had a real nice opportunity to try out the AT102. I did a little comparison with the SW120 but mostly I just wanted to get a feel for the scope.
The quick version: If you are on the fence about this scope, don't be, just grab one. It is excellent. Overall I felt it outperformed its aperture.
I used mine mounted on a Vixen Superpolaris mount set in alt-azimuth mode with Vixen aluminum tripod legs and a set of anti-vibration pads that really weren't needed. It was a solid smooth set-up. The focuser was very smooth and stable and the fine focus allowed for vibration free focus with no backlash. The nice thing about this focuser is that I know I don't have to even think about upgrading it - unlike what I ended up doing with my SW120ED.
Optically it was super-sharp. I mostly used the 30mm APM UFF (24x, 3.0 deg TFOV) and the 18.2mm DeLite (39x, 1.5 deg TFOV) and the 18.2mm DeLite with the 1.6x Nikon and 3.0x TV barlows. I did use the 9mm and 6.5mm Morpheus a little as well. With the barlows the 18.2mm DeLite gave 63x and 120x. So most of my observing was 24x, 39x, 63x, 120x.
30mm APM UFF: I used this eyepiece quite a bit. It provided clear, sharp views with no EOFB. It was not sharp to the field stop, but there was minimal fall off and surprisingly I think the edge performance stayed about the same with the AT102 as the SW120. With the 80mm SV Access there is a pretty noticeable drop in edge performance. Highlights with this eyepiece include:
~Framing NGC7789 and neighboring bright stars in the field with room to spare and the bright stars sharp.
~M24 star cloud and dark nebula
~M8 with a Lumicon UHC filter ... and spans of nebulosity below the Lagoon that I had never noticed before. While the high quality of the AT102 contributed to seeing this, so didn't the exceptional sky conditions last night.
~M6&7 star clusters
~M22 - suprisingly resolved at 24x
18.2mm DeLite: This is something I was looking forward to. I really like the image scale at ~40x possibly more than any magnification below 100x. However, the 18.2mm DeLite gives 50x with my 120ED. The 39x it gives with the AT102 was perfection from start to finish. It began with my first target of the night - open cluster NGC6819 and ended with NGC 457 as my last target of the night and everything in between.
The eyepiece is super sharp and the field is really clean with the AT102. The exit pupil is 2.6mm and the image scale is really nice. It did not matter what I looked at, the 18.2mm DeLite with the AT102 was a continuous "wow".
Surprise of the night: How much nebular detail and resolution of start clusters the AT102 provided compared to the SW120. I first noticed early on when I got to M27. At that point I had the SW120 out cooling in its case but I wasn't sure if I was going to use it. So I grabbed my mount for the 120 and did some back and forth comparisons for a few different objects, but mostly comparing M27, M17, and the M24 starcloud with NGC 6603. I didn't feel the amount of visible difference was in line with the aperture difference. I consistently felt that the AT102 was outperforming its aperture.
Higher magnification deep sky: I stuck within my normal exit pupil limits for deep sky but the AT102 easily handled exit pupils <1mm. Most common was the 18.2mm DeLite with the 3x TV barlow for 120x magnification. DSO still seemed sufficiently bright and the scope continued to present pinpoint sharp stars.
The other nice thing is how light and portable this scope is - particularly having that sliding dew shield to pack it up at the end of the night.
Anyway, nothing but praise for the AT102.