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I was reading up about the Mewlons recently. Among glowing reviews, the only negative I've come across is the reportedly limited back-focus of the 250. (I don't know if this applies to the 300.)
The discussion below came from the Tak Yahoo group. It looks like you can fit in a camera, adaptive optics unit and a reducer if you have the right bits and pieces, but I haven't been able to ascertain how difficult this is in reality.
I suppose you've looked into this. Has anyone any more info? If it's not a problem, I'd be keen on an M300 myself.
[UncensoredTakGroup] Re: Mewlon 250
"Well I have had my Mewlon 250 on its EM200 mount for several months now. It tracks perfectly and has tremendous optics. It is a very good visual scope and is fine for prime focus photography where the camera is placed right at the visual back of the telescope.
My biggest concern about this telescope is that compared to my Celestron 9.25" scope it has very little backfocus. I find this to be a really major problem."
"Hi Paul: I forgot to address the back focus so called problem with the
mewlon-250. It all depends on how much stuff you want to hang from the mewlon. There is a low profile adapter for the mewlon-250 for less than infinity and also equipment trains. I have the mewlon-250 and FS-102 on a NJP mount. Also the secondary can be lowered a little closer to the primary for focusing with the longer equipment trains."
"Hi Rick, my push set screws on the secondary are almost flush with the top of the ring. I have a mewlon-250 also and use the optional cassagain focuser/rotator, I seem to have a lot of back focus. The secondary height will help with more back focus, the closer to the primary the more back focus."
"Takahashi makes a shorter version of the 2" ocular adapter that is
about an inch shorter than the standard version."
"I had the same issue with the lack of back focus on my M-250. I
couldn't get my ST-10, AO-7, and reducer setup to come to focus.
After speaking to Fred at TNR, I moved the secondary/focuser unit
back a bit. With this adjustment, and a custom made short ocular
holder, I am able to get enough back focus have my ST-10, AO-7, and
reducer come to focus. I would suggest that you talk to Fred before
making any adjustment to the secondary."
"http://www.astrofactum.de/Astrofactum/index.htm
Using this clamp you will get about 22mm more back focus. It is
designed to hold havy binoviewer or ccd camera equipment in place.
Heiko."
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