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IM 715,703 or Tak mewlon 180

Started by cysmarc, 12/16/2007 12:40PM
Posted 12/16/2007 12:40PM Opening Post
Well the title says it. What would you go for?
My observing habits are planets, doubles, globs and nebulae (orion, dumbell, ring, swan ..) I do not go much for galaxies for at 7 inches it will still be a faint fuzzy.
The longer fl of the 715 will be very good for the planets and (I think) that for the dso's that I go for the small fov should still be good.
The Tak has a shorter fl but has a spider I think that the co is similar to the 715.
What do you guys have to say?
Posted 12/16/2007 01:08PM #1
Unless the Tak is significantly cheaper, I wouldn't want the large coma that the Dall-Kirkham inherently has. I think of the D-K as a good high power lunar/double star/planetary scope. However, I see the Tak 180 losing out to the IM 703 off axis because of the coma and essentially tying it on axis, and I see the Tak 180 again losing this time on axis to the 715 due to it's smaller CO.

The only other factor that may come into play is some of the Intes and IM scopes I've seen are a bit rough mechanically, while the Tak is "like butta". Perhaps IM has gotten better since I last saw one?

In any case, I would probably spring for the 703 and give up a bit to the 715 but gain a more flexible scope. If I had a different wider field scope, I would spring for the 715 for lunar/planets/double stars.

Posted 12/16/2007 01:51PM | Edited 12/16/2007 01:52PM #2
I have had very good luck with the I-M Maks and Mak-Newts. Since you have the 4" refractor and you tend toward planets, doubles and globulars with some DSO work as well, I would think the 715 would be a good choice. Two I-M Maks have passed through my hands, a 6" F/12 and a 10" F/12.5 and several Mak-Newts from the MN56 to MN76. The 10" and MN76 were stunning, the smaller two were solid performers as well but a tad small for my tastes.
Posted 12/17/2007 06:49AM | Edited 12/17/2007 06:50AM #3
After having owned an f/10 STF Mak and a Mewlon 180, I would say Philip is right on with the tie or close tie with on axis performance between the 703 and M180. There is coma off-axis on the M180, but I never intended to use it as a wide field scope. Both scopes I owned were extremely good at lunar/planetary/double star work.

IMHO, the IM715 would be worth a serious look. I have a good friend that owns one and he uses a .63 focal reducer when he wants to observer deep sky. Sounds like the best of both worlds to me.