6" CC for doubles?

[Mr Spock]

With my light pollution I'm getting a bit frustrated with the 4" only reaching mag 10.0 most nights. I reckon I need something which can go fainter, but will still fit on an EQ5.

I'm thinking about the SL 6" CC. At £429 it's not that expensive, plus it gives an extra 0.9 mag over the 4". In addition it has a 'proper' focuser instead of shifting the mirror up and down as with Maks.
Negative is I won't have the wide field 'finder' view of the 4". It can manage 1.5° with the 42mm LVW, so I'm hoping that will be enough; I can fit my 8x50 RACI to it so all is not lost though I would prefer an RDF.

Thoughts anyone?

[bosun21]

I have owned both the 6" SL CC and the 150 SW Maksutov and for doubles and stars in general the mak is far sharper with no diffraction spikes. I see hardly any mirror shift with the newer maks and even then it's tiny at very high magnifications. You could always fit a standard dual speed focuser to the visual back and eliminate the mirror shift altogether. Oh and the CC is a pain in the proverbial to collimate.

[Mr Spock]

Yeah, I've had a Mak before and it was really easy to collimate - and sharp too. It was a OO140 with premium optics (better than they sell now) - absolutely dire focuser though.

I can keep it in the shed so cooldown wouldn't be a problem.

[Mr Spock]

I note the Bresser 152 has a R&P focuser. Horrible finder though.

[John]

I'm interested in a Mewlon 180 for similar reasons 🙂

It still has diffraction spikes though 

[lunator]

Hi Michael 

The CC would be a very good scope. The only downside I can see is the 38% CO might affect close uneven doubles resolution. It's not a big issue as my OMC250 has a similar CO. 

Cheers

Ian

[magnahrl]

I have had a second hand CC8 for ca 1 1/2 month. Not used it much due to lumbago pain  and too short dark nights here at 57N.  But the little I have observed with it indicates sharp, nice stars at 300X. Almost like a biggger version of my Intes MK66. I bought it for doubles and planetary observations. And because it`s not so sensetive to dewproblems (?) and of course I got it for a good price! And I could also test the scope before deciding.

The CC is a special kind of scope with it`s narrow field of view and the spikes . I dont`t find the spikes to be any problem though. I can only see them on brighter stars. And they will appear when observing planets. Anyone who find the spikes to be irritating should stay away from CC:s  and  Newtonians as well.

I will evaluate this CC8 in mid august when darkness returns. Will be intressting to se how it holds collimation and if the horrorstories about collimating are true. This scope is a project for me but this far it`s been promising🤫I have never used a CC before!

 

Magnus A.

[Oscar23]

Can't comment on the CC - I'll defer to Magnus on it. Diffraction spikes, either you can deal with 'em or you can't. But I do like Maks. My dad bought his 4SE used, not sure how old it is exactly but it's been around the block. The optics, far as my eyes can see, are still in perfect collimation (not that there'd be any way to fix it, but no need, no problem). There's something to be said for the simplicity of the secondary on a Mak. Very sleek. Mirror shift... we haven't seen it yet in the 4SE, and of course there's fixes and workarounds for it as mentioned. The only thing I don't like is that it's got the diagonal built in. They're robust and very effective little scopes. So, if I were buying a 6" Cassegrain for myself, I'd get a Mak.

[Mr Spock]

I think at £429 the CC seems a good price compared to the Mak which is £619. I'm not so much bothered by diffraction spikes; they'll only be on bright stars anyway as observed with my 12" Newt. With the Mak it would have to have a dewshield added to the cost.

I've already got in the post a 60mm finder which can take eyepieces. So I'm thinking a 13mm Nirvana would give x18 and 4.6° which is more than enough for me to star hop on fainter stars. That would make up for the narrow FOV on the CC. I'm used to using a 42mm LVW in my 4" Tak as a finder to star hop - that is 3.7°.

It all gives me what I want and doesn't break the bank (I'm a poor pensioner lol). FLO has them in stock so it's a done deal.

[Oscar23]

Put a 24mm UFF (or similar) in that finder for fun I think your LVW 22 would also give you around 5.3° TFOV, assuming I approximated your finder's focal length closely enough. 234mm or so?

Edited May 23 by Oscar23

[IDM]

This may not be relevant but I used to have a CC8 with primarily used for imaging planets and I never got on with it. The focuser is poor, The need to change the back focus using the supplied rings was difficult. Its very heavy for the aperture. I have now sold mine for a very low price so I don't think they hold their value. I bought due to people saying how difficult SCT's are to manage due to dew issues and thermal cooling of the tube. I have however recently picked up a secondhand C8 and have had no problems, I simply leave the scope out from early afternoon on any night its forecast to be clear and use a dew shield and heater band, its also easy to focus and every time I pick it up it makes me smile as its so light and easy to manage and mount compared to the CC8.