To Mod or not to Mod

[Hans Tucker (Hans)]

A few years ago I purchased my Mewlon 250S which is a native f/12 scope. Takahashi have released a 3 element ED Corrector ($1100 US)contained within a replacement baffle tube assembly. This new corrector supposedly eliminates coma, flattens the field and reduce the f-ratio slightly to f/10 I think. There is also a 0.73X reducer (f/7.2) ($699 US) and 1.5X (f/14.9) ($499 US) available for use with corrected Mewlon to turn it into a Tri-Focal scope. The question is would it be a good idea to make this modification or should I leave it as an f/12 scope? I can see a lot of positives to this but is there any negatives that may be overlooked?

[loc46south (Geoffrey)]

Hi - I am in the process of setting up a M250 as an imaging scope. If you want a visual scope then leave it at f12. If you want a planetary imaging scope again leave it at f12. If you want to use it for DSO's then you will need to get the corrector and the reducer - personally I wouldn't bother with the 1.5X extender. Without them the scope is far too slow - even at f10 you may still have to resort to binning your image to cut exposure times.

[gbeal]

Hans, while each will have a differing slant on this, I'm with Geoff. I have the M210, and while it isn't the M250, it is mighty slow, and imaging isn't really what I bought it for. Visual, or lunar and planetary is fine, but DSO's, nope, you can do better I reckon.
To get the feet wet with longer focal length DSO imaging, use the money you had earmarked for the "upgrade" and grab a used 8" R/C. Try it and see. If you can live with the F8 that these typically are, then maybe think about the M250 and reducer. Maybe.
Gary