As to the scope that's being reviewed here, I noticed there were some discussions when these Bressers hit the market originally, and always there were issues with the lens cell and – as BB explicitly says – especially with the too-flimsy retaining ring and that ill-fated non-circumferential threading.
However, I also notice that once these issues have been dealt with, the Bresser 102L seems to be capable of very nice high-power views. What BB describes on the Moon, sounds very promising to me.
I am still curious how false color is compared to other Achromats. My personal experience is that I don't bother about any false color in a 60mm f/15 and also an 80mm f/15. I do find it a bit disturbing in my 90mm f/11 sometimes, but still like the pinpoint sharp stars and also the crisp lunar details in this scope a lot. Huygens eyepieces are much better with achromats as they seem to cancel out some of the false color of an Achromat, but I don't have many quality ones yet.
Theoretical calculations tell me that the 102mm f/10 should be considerably worse than the 90mm f/11, while a 102mm f/13.4 should be very similar.
So my current impression is I wouldn't want to buy the Bresser
(1) cause I also dislike the flimsy lens cell. I repeat again I would not mind if the focuser would be much simpler. What's the point of that rotating feature and generally more elaborate design at this price point? Especially if it comes at the expense of the much more important lens cell.
(2) in my opinion the false color is maybe just a bit too much (if what BB said so far is true, that it kind of matches the 4" f/10). I'd rather want a 90mm f/14 then, or jump to an ED scope / other scope design instead. Maybe the Bresser 90/1200 would be more "my" purchase. It's even more cheap and maybe even better in color correction. (t's maybe too close to my 90/1000.) The problem is that the Bresser is no classic. You love classics because of all kinds of other reasons than just their "perfect" performance. The Bresser, though, is a new scope. I see that with different eyes.
(3) I'm not sure if buying a classic achromat means more hassle than buying this thing brand new, if it still involves all that fuzz about sorting out the lens cell and collimation before you can put it up to good use. But, YMMV. It surely is nice that Bresser cares for that niche despite all these issues, and let's hope they maybe get some stuff right if they ever happen to modify their offerings.
I fully understand that mirror optics can also be excellent, I have (had) some myself. But that's an entirely different discussion which is off-topic here.
Edited by memento, 14 April 2019 - 12:16 PM.