Maksutov-Newtonian?

[michaelmorris]

I'm researching upgrading my ageing 8" LX200 classic as the main scope in my observatory. I already have a 80mm apo and a guide scope. I had settled on getting a Celestron 9.25", but now I'm having second thoughts. I'm thinking more and more about getting a Maksutov Newtonian as I am getting more and more into visual double star observing.

However, I also need the new scope for planetary imaging and for deep sky imaging using initially a dslr and later using a ccd camera with filter wheel. Will a Maksutov Newtonian produce a good planetary image with a 5x powermate? Will it have enough back focus with a ccd and filter wheel?

Thanks

[wavydavy]

I have the mak Newtonian MN190 by skywatcher................what one are you thinking of getting? I can reach focus with my filter wheel and my atik 314, however, if I use an OAG I cant, and would have to upgrade the focuser to a moonlite or something similar with a shorter tube. So for me I have a separate guidescope.....let me know what you thinking of getting. My reason for going the mak newt route was that I hate coma I kept getting with Newtonians.

[michaelmorris]

Yes it's the SW MN190 I was thinking of.

[wavydavy]

Its a great scope............its way better than a standard newt, no coma, flat field, and optimised for imaging.........

[DaveS]

Yes, it sounds a great 'scope but I've also read that they need extensive fettling before they're really usable, pretty much a full strip-down and rebuild with a new focuser and serious attention to the mirror cell, one reason for excluding it from my imaging to-buy list.

[Peter Drew]

DaveS.  Can you point me to where you read of these comments, we have been bequeathed a MN190 but haven't had chance to use it yet. It would be interesting to know what might be needed. 

[DaveS]

I'm trying to find it, but there was a long thread by a member who replaced the stock focuser with a Moonlight, and Per has said the mirror cell needs to be more stable. Putting those together involved taking the whole thing apart to fettle it.

It's possible that I'm over-reacting and that one would be fine "out of the box" but it's put me off considering one. That and the fact that I'd need a new mount at a higher level.

[Stu]

3 minutes ago, DaveS said:

I'm trying to find it, but there was a long thread by a member who replaced the stock focuser with a Moonlight, and Per has said the mirror cell needs to be more stable. Putting those together involved taking the whole thing apart to fettle it.

It's possible that I'm over-reacting and that one would be fine "out of the box" but it's put me off considering one. That and the fact that I'd need a new mount at a higher level.

This one?

 

[DaveS]

Thanks Stu, that's the one. Put the wind up me good 'n' proper given my cackhandedness.

If I did buy a MN190, I'd be looking to fit one of these:

https://www.firstlightoptics.com/starlight-instruments-feather-touch-2inch-crayford-focusers/feathertouch-crayford-focuser-for-newtonian-telescopes.html

Which looks to come with a base-plate to fit the Skywatcher Explorer range of 'scopes.

[Stu]

57 minutes ago, DaveS said:

I'm trying to find it, but there was a long thread by a member who replaced the stock focuser with a Moonlight, and Per has said the mirror cell needs to be more stable. Putting those together involved taking the whole thing apart to fettle it.

It's possible that I'm over-reacting and that one would be fine "out of the box" but it's put me off considering one. That and the fact that I'd need a new mount at a higher level.

I may be wrong on this, but wasn't the reason Per needed to modify the primary cell related to his unguided setup and the need for complete stability to allow his sky model to work correctly? With a more standard setup, I think it is less of a problem? But hey, I just look at stuff through my scope so what do I know? ??

I've always fancied an MN190. One day perhaps...

[DaveS]

I think that was the case, and I've been over-thinking things.

Still muttering about going unguided with an ASA DDM60 (Don't let Olly hear!), so I'd be in the same situation of needing stability.

 

 

***** Goes off muttering about big triplet apos ******

[Peter Drew]

Thanks DaveS and Stu. The post made an interesting read. Collimation doesn't frighten me these days, I also have a MN56 which I diismantled and fitted a different focuser, I don't expect the MN190 to be much different, we will see. For visual use they are just F6 Newtonians with an added corrector.