Ended my observations with the Bresser AR-102L on a high note, and with some of the traditional long refractor objects: Double stars & star clusters. I spent 2 hours last night in Bootes & Coma Berenices with my excellent 1971 Criterion RV-6 Dynascope, and I returned to those constellations tonight with the AR-102L.
DSO seeing tonight was 9 / 10. Drier air than the 3 or 4 previous nights, which also made it feel a bit cooler. I could easily see Alpha CB (V=4.35) with my own eyes.
I put the AR-102L on my Meade StarFinder pedestal version, so the eyepiece was at a comfortable height for observing at the zenith. Light as the Bresser is, the rig was vibration-free up to 200x. I used a 2" dielectric diagonal with 1.25" adapter for most observations. No issues with the focuser.
I've observed M3 with at least a dozen different scopes over the past few weeks. The AR-102L presented the cluster well for a 4" refractor. I got resolution of the outermost fringes at 150x, and the view stayed sharp & bright enough at 200x with UO HD 9mm & 6mm Orthoscopics. M53 looked to be about half the extent, but also held relatively sharp & bright at 200x. Background sky was charcoal to black.
For a small constellation, CB has some spectacular double stars. 24 Comae (5.2, 6.5; PA 271º, separation 20.3") is the most impressive: Brilliant orange primary, & cool blue secondary. In my APOs, the secondary is a blue-gray with a hint of deeper blue or violet. In the AR-102L, it's blue with a bit of green. (As a cross-check for colors, I had my Takahashi FC-50 set up on the VersaGo last night.)
The 30mm finder isn't much help in star-hopping to the DSOs you can see in this refractor. On my 4" & larger scopes, I use a minimum 50mm finder, and the AR-102L needs one. Using memory, I located M56 & M100. Again, the views of these two galaxies at ~ 100x was good for this aperture -- plenty of detail for sketching.
IMO, the AR-102L does well with the DSOs I'd target with a high F-ratio achromatic refractor. I have larger reflectors for observing faint fuzzies, but even these can be viewed with the scope, and I find the differences interesting.
Edited by Bomber Bob, 26 May 2019 - 10:18 AM.