Mak or sct

[astro1965]

Hi all, was just wondering wether a Mak or SCT would give a sharper(con trasty) view.Have read various reviews that say a well collimated,cooled SCT matches the views through a Mak,others say the Mak is far superior.Would like some input from those who have owned both these scopes at some stage.I am thinking of one of these as a second scope.Currently have a 12 inch dob.Thanks,Nick.

[casstony]

What aperture are you looking at Nick? Visual only or imaging as well? Planets or deep sky?

A 4" ED refractor or an 8" Celestron Edge HD are both useful scopes. The vents make it easy to add active cooling to the Edge. Cooldown is a serious issue with closed tubes in our temperate climate.

[astro1965]

Hi,I would be strictly visual and my interests are both planets and some bright deep sky stuff.Since I have a 12 inch dob,I think something in the range of 6 to 8 inch aperture.

[MortonH]

I had a Skywatcher 6" Mak-Cass and now have a C6 SCT. The Mak may have been slightly sharper and had a touch more contrast but the C6 is very good. On deep sky the C6 is brighter, perhaps due to having Celestron's best coatings.

One of the issues with OLDER Skywatcher Mak-Cass scopes is the primary mirror is undersized for the corrector, meaning that the effective aperture is more like 140mm. The latest models have oversized primary mirrors to correct this issue.

SCTs are also lighter than a Mak of the same aperture. A 6" Mak weighs about the same as a C8.

Both scopes have some thermal issues in winter but not nearly as bad as a C8 I once borrowed.

[AG Hybrid]

Newer Skywatcher Mak's have had the downsized aperture issue resolved. It was caused by baffling being too restrictive.

I suggest you spend some time in the Cloudynights forums and check out their "Cats & Casses" section. I spent a several good hours there reading over the materials available and chose the MCT myself.

[MortonH]

The comments I've read were all about the primary being undersized, not an issue with the baffling. The corrector in a Mak-Cass diverges the rays slightly so the primary mirror needs to be larger than the corrector otherwise some light is lost.

Is there something that confirms the issue has been addressed?


EDIT: This thread on CN confirms that new Synta Maks have larger primary mirrors and are operating at full aperture.

http://www.cloudynights.com/topic/533792-at-last-a-skywatcher-180-v-intes703-direct-comparison-possible/

[AG Hybrid]

Were they measuring the size of the primary and path of the light rays with the "Torch test"? That's been deemed as inaccurate now. A laser test was developed that's far more accurate. Maybe its a different issue, but there was also a vignetting issue that reduced effective aperture due to the rear baffle being too narrow.

The new versions have a wider rear baffle. Confirmed by a user on CN who spoke with an Orion engineer who confirmed it. But, the new Skywatcher and Orion Mak's are now working at the advertised aperture.

[MortonH]

That's good to know. :thumbsup:

[AG Hybrid]

I picked up my MAK as a special instrument to go with my 12". A long focal length instrument for lunar/planetary and double stars that has tracking.

[dannat]

once you've had Mak you won't go back, though above 6" they become too pricey compared with SCT & some don't like the long focal lengths

the 6" mak astromelb has for sale in classifieds would be a good buy, cool quicker than your 12" & give good blk backgrounds

[ausastronomer]

Hi Nick,

Assuming there are no manufacturing or design flaws and everything else is constant, then an equal aperture Maksutov Cassegrain should slightly outperform an equal aperture SCT, as a lunar planetary telescope. There are optical reasons for this. However, when you start to introduce design and or manufacturing flaws like the undersized primary mirror and or the undersized baffle tube discussed above by Adrian and Morton, then everything changes. If you could locate a 2nd hand Maksutov Cassegrain from Intes, or Intes Micro, or the 7"/F15 Meade LX200 Maksutov Cassegrain you would likely find these to be better scopes optically than the newer offerings made in the far East. These occasionally come up on Icetrades and often come up on Astromart. They sometimes come up really cheap also, but with no mount. You may of course be happy with a reasonable performing scope and just buy a new one from Skywatcher or Celestron. The prices on these have come down dramatically in the last 20 years in relative terms.

Notwithstanding the mirrors on this 7" Intes needed a recoat it was a steal at $500 (http://www.iceinspace.com.au/forum/showthread.php?t=135604) It's a better telescope than anything made by Celestron and Skywatcher.

Cheers,
John B

[g__day]

Besides the weight of the MAK - generally I have found the SCT is a lot easier to collimate than a MAK is - if that is even possible of some MAKs...

[astro1965]

Thanks guys for all that info,funnily enough,there is a Meade 7 inch Mak for sale on ebay at the moment,but I was really only after the OTA and this one on ebay comes with the fork mount and tripod.Looks very nice indeed.
The more reviews I read ,the harder it gets to decide.Does anyone have any experience with the Skywatcher 7.1 MaK? I would only use it for visual observing.Thanks Nick.

[MortonH]

The thread on CloudyNights in post #6 has lots of info on the Skywatcher 180mm Mak. Worth a read.

[astro1965]

Thanks Morton,will check it out.

[ausastronomer]

Pity that. I am not a Meade fan and I don't normally push their gear. I don't own and have never owned one single piece of optical equipment made or sold by Meade and never will. But I have to say the Meade 7"/F15 Maksutov is an outstanding telescope and one of the very best telescopes Meade ever made. These were made in the Irvine California factory.

Cheers,
John B

[Hol_dan]

I would choose a Celestron SCT 8 over a 6" mak simply because of the extra aperture, less weight and wider field with any given Ep.

Celestron scopes are great and many accessories for them.

[raymo]

I'm with Holly, but I would choose a 7"Mak over an 8" SCT.
raymo

[AG Hybrid]

Good guy Mak-Cass.

Completely dismantled while its main tube and primary baffle can be flocked.

Still collimated once reassembled.

[MortonH]

There are lots of people on CloudyNights that rave about the Orion (Synta) 127mm Mak-Cass. I've always fancied trying one since they're so compact. Central obstruction is only 30% so contrast should be reasonably good, certainly better than a typical SCT.

If anyone reading this has a 127mm they want to sell , send me a PM!

[Wavytone]

Morton from mine at least, the Skywatcher 180mm Maks out-resolve most C8 or Meade 8" SCT's on lunar and planetary. Contrast is also better. The image is however noticeably dimmer in side-by-side comparisons with a C8.

A C9.25 EdgeHD or 10" Meade ACF however is a match in most respects with better light grasp (aperture) and if a good one came up secondhand I'd say buy it.

Ultimately up to you.

If I had $25k to spare and the time to go observing, I would definitely order one of the APM 275mm f/14 Maks currently on Astromart without hesitation. But I haven't got the time anymore. Maybe when I retire...

[Camelopardalis]

I used to have one...it got replaced by an orange C6 :P

The C6 cooled quicker and has almost 2x the light gathering for fuzzies, giving up nothing when it came to planetary.

[AG Hybrid]

I find the cool down time of my 150 to not be bad at all. About an hour. Then again once been conditioned for the last six years to wait for a 12" to cooldown. I think people exaggerate how long it takes. Maybe it's because they ate often compared to little refracters. But Then a 5" or 6" refracter still takes some time to cool down.

[astro1965]

Does anybody have any opinions whether there is a difference visually between a 6 and 7 inch Mak or would the views be very similar and not worth going for the 7 inch.Thanks,Nick.

[MortonH]

I've had both sizes and would say the 7" would be a worthwhile improvement. Of course the negatives are more weight, longer cool-down, etc.

[Camelopardalis]

I think on the east coast of NSW, QLD there's a gentler temperature gradient between day/night/inside, compared to most over the big pond that bleat about it when they take it from a heated house to a sub-zero deck :rolleyes:

[MortonH]

That C6 is a great scope and a keeper! :)

Have had an offer to borrow a 127mm Mak so will be interesting to compare them side by side on the planets.

[raymo]

I think your figure was a bit off, Morton. The C-6 has slightly less than
1.5x [1.44x] the light grasp of the 127mm, not slightly less than double.
cheers raymo

[dannat]

ray it wasn't morton that suggested it almost Dbl light gathering

[Camelopardalis]

Yeah my bad :lol: I was thinking C6->C8...

[MortonH]

If the 127mm Mak is an older one with effective aperture of 118mm, and taking into account Celestron's superior coatings, I estimate that the C6 could be transmitting about 80% more light to the eyepiece.

[MortonH]

FWIW, I've just been viewing Mars at 250x in my C6. Great little scope. :)

[raymo]

My humble apologies Morton.
raymo