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6" Mak or Classical Cassegrain?

Beginner Cassegrain Maksutov
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#1 Maks343

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Posted 10 August 2021 - 12:42 PM

I am new to the hobby and trying to decide on what scope to go with.  I had narrowed down to either the Skymax 127 or 150, but then I came across the AT6CC and the turmoil reignited.  Unfortunately, none of these options are in stock anywhere so I still have time to do some research.

 

My budget is probably in the $1000-$1200 range, to include the Celestron CG4 mount I'm considering.  I plan to use the scope visually for planets/moon/sun and splitting binary/multi systems.  And I live under light-polluted suburban skies, so portability is one factor in looking at the Mak/CC platform.

 

I have read thru a number of the postings here and find that the discussion inevitably gets way more technical and advanced than my caveman understanding.  So I guess what I'm looking for is some input/advice on which optical system would be better suited to a) my circumstances and purpose, and 2) my lack of astronomical sophistication.  Or are the Mak and CC similar enough as to make it a moot issue?  Is there a better 6" Mak to consider?

 

I should add that I have no gear (mounts, EPs, diagonal, etc.) currently, so this would be a new start.  I'm not asking anyone to make my decision for me, just to help me cut thru the minutia to see the big, simple picture.

 

Thanks in advance.


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#2 RajG

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Posted 10 August 2021 - 01:24 PM

Looks like Orion has the 6in CC in stock. There is a long discussion here:

 

https://www.cloudyni...cal-cassegrain/

 

Performance-wise the mass market CCs, Maks and SCTs are all good choices, differences are likely more due to in-sample variation than inherent superiority of any one of these designs. Be aware that the true aperture of the 127 Mak is actually 118mm, and that of the 6in CC appears to be 136-140mm. The Skymax 150 Mak and 6in SCT appear to work at full aperture, based on what I've read on CN.

 

A few points:

 

1) The 6in SCT is the lightest at about 8lbs, the 6in Skymax Mak is ˜11lbs, the 6in CC is heaviest at about 12lbs (OTA weight only). There is also the IOptron 6in mak (a different design) but it is more expensive and even heavier.

2) SCTs and Maks are more subject to dewing. As the CC is an open tube design, it is immune to dew but will have diffraction spikes due to the spider (which is really a matter of personal taste not an inherent flaw).

3) SCTs and Maks tend to have longer cool down times, but if insulated they don't require any cooldown.

4) Collimation on CCs can be more challenging than for SCTs and Maks.


Edited by RajG, 10 August 2021 - 01:26 PM.

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#3 RajG

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Posted 10 August 2021 - 01:32 PM

BTW, if you are just starting out and don't have any gear yet, consider a 6 or 8 in dobsonian. They are much cheaper, typically come with 1-2 eyepieces and include an alt-az dob base. So you won't need extra gear right away...


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#4 Supernova74

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Posted 10 August 2021 - 01:38 PM

Lol why is it that an OP requires advice on a particular optical design of a scope ie in this case a maksutov or a cassagrain.then all of a sudden typically the dob is thrown into the mix.we don,t know yet what his or hers preferences are yet or even there observing style.


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#5 dweller25

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Posted 10 August 2021 - 01:40 PM

RajG has summed it up perfectly.

 

A CG5, EQ5 or Vixen GP mount would work best with the Skymax 150 and AT6CC, the C6 is very light and would be OK on the CG4.

 

For me the choice would be the SW 150 Mak as they are well built, get consistently good reviews and hold collimation well. I would also add two layers of thermal insulation to avoid the slow cool down issue plus it holds the dew off.

 

But thats me - good luck with your choice waytogo.gif


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#6 barbarosa

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Posted 10 August 2021 - 02:17 PM

 

My budget is probably in the $1000-$1200 range, to include the Celestron CG4 mount I'm considering.  I plan to use the scope visually for planets/moon/sun and splitting binary/multi systems.  And I live under light-polluted suburban skies, so portability is one factor in looking at the Mak/CC platform.

 

 

I agree with most of what has already been said. For the targets you identified the answer is some ways is comme ci comme ca.

 

My points of difference are not critical but here they are-

 

Maks, unless handled very roughly are never going to need collimation. Compare the number of posts about collimating SCTs and Newts with those about Maks. You will not have to clean the mirror with a Mak.

 

The impact of dew varies considerably by location. Where I am no scope is immune to condensation. It's dew heaters, dew shields, insulation and shields up most times of the year. 

 

Insulation is a hot topic on CN. There is some science involved, usually lost in the discussion. I see the primary advantage as moving condensation from the optical tube to the outer  face of the insulation. The other advantage for me is that a dew heater under insulation requires less power for equal effect. Don't make dew a critical factor. Don't worry about insulation. 

 

Mount choice- Over mounted beats under mounted every time.

 

What do I recommend in your price range? Something on a go to mount., Nexstar 6 or Evolution 6.

 

Why? There is a lot more to see than double stars and a go to mount makes that much simpler. Plus it is a good platform for live imaging (EAA). EAA brings many objects into view that are otherwise just gray fuzzy things and it does so in color.

 

Alternate scope choice- a 6" or 8" RC.

 

 

Whatever you decide enjoy it. This is a great hobby.


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#7 Supernova74

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Posted 10 August 2021 - 02:27 PM

Well just to add if you would to like to know the quality of the 150mm maksutov optics.and what thay are capable of approximately 3 years ago when I owned the skywatcher (synta) on par with the celestron,Orion USA equivalents.i took this simple snap shot of the moon in useing this very iPad mini 4 with only 5 megapixel camera over the eyepiece.ok admittedly it will not win any awards soon however considering the very basic tools I used I feel it’s really not that bad.

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#8 Maks343

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Posted 10 August 2021 - 07:42 PM

So am I correct that of the three types, the Mak is the minimal maintenance/ease of use winner, aside from the dew/cool down issue?

 

What would be the advantage of the SCT over the Mak?

 

And isn't the RC an imaging specific design, not really suited for visual only users?



#9 RajG

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Posted 10 August 2021 - 08:12 PM

So am I correct that of the three types, the Mak is the minimal maintenance/ease of use winner, aside from the dew/cool down issue?

If by minimal maintenance you mean collimation, then likely yes. Ease of use is basically identical across all three designs

 

What would be the advantage of the SCT over the Mak?

Weight. The SCT is significantly lighter, so you can get away with a less beefy (hence cheaper) mount. It has a shorter focal length than a Mak, so you can get slightly wider fields and lower magnification with the same eyepiece. Also SCTs are a bit more versatile - you can get an f/6.3 reducer, or a hyperstar which will convert it into a very fast f/2 imaging scope.

 

And isn't the RC an imaging specific design, not really suited for visual only users?

Correct, the RC (Ritchey-Chretien) is intended for imaging. It typically has a large central obstruction (50%) to minimize vignetting, but as a result it is not very well suited for visual use due to loss of contrast. 

 

Don't confuse an RC with a CC (classical cassegrain) which is an entirely different design. CC's are intended for visual use.


Edited by RajG, 10 August 2021 - 08:14 PM.


#10 vahe

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Posted 10 August 2021 - 08:53 PM

 I plan to use the scope visually for planets/moon/sun and splitting binary/multi systems.  And I live under light-polluted suburban skies, so portability is one factor in looking at the Mak/CC platform.

 

 

 

One major difference between a Mak/SCT and classical Cassegrain is the secondary support which generates diffraction spikes, some folks get used to diffraction spikes and some just can't stand it. I personally prefer Maks for their refractor like images when it comes to bright planets.

Anyway, something to consider in an effort to avoid unexpected surprises.

.

Vahe


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#11 barbie

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Posted 10 August 2021 - 09:04 PM

I've observed with classical cassegrains and Maks and have seen both designs do well but prefer the Maksutov-Cassegrain for lunar, planets and brighter binaries.


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#12 Maks343

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Posted 11 August 2021 - 05:30 PM

There's a substantial ($300) price difference between the CC and SW 150.  Is there that big a manufacturing cost difference between having an open tube design vs the corrector lens or is there some other reason for the gap?



#13 RajG

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Posted 11 August 2021 - 08:33 PM

The SW Mak comes with a 2in diagonal, finder scope and eyepiece, while the CC is sold as an OTA only. Also Skywatcher recently raised their prices. The CC's are made by GSO and haven't (yet) gone up in price, so they are a relative bargain.



#14 Maks343

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Posted 11 August 2021 - 08:55 PM

Got it.  So since I don't have a diagonal, finder scope or EP, by the time I outfitted the CC with those items I'd probably have spent about as much as the SW.  Without that gear the CC would just be an expensive paperweight, correct?

 

Of the 6" Mak options, any thoughts on the better/best as far as optic quality, included components- that sort of thing?  Again, I'm going to be using it for visually for brighter targets.

 

And does AT offer a Mak or is the CC it?



#15 RajG

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Posted 12 August 2021 - 07:52 AM

Yes, you would need to buy them separately but they probably won't add up to $300 in cost. Of course if you buy premium items  they could add up to considerably more. 

 

Optically the Meade, Celestron, Orion & Skywatcher Maks are essentially identical. I think they are all made by Synta. The Orion Mak comes as OTA only, or bundled with the Star Seeker IV mount in which case you get a complete kit with goto mount, finder, diagonal & eyepieces. The IOptron is a different design and is supposed to be better but it is more expensive and heavier.

 

AT sells the SW & Celestron-branded Maks. They also sell Questar which only comes in 3.5in & 7in versions,  these are legendary but very expensive.



#16 luxo II

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Posted 12 August 2021 - 07:58 AM

There's a substantial ($300) price difference between the CC and SW 150.  Is there that big a manufacturing cost difference between having an open tube design vs the corrector lens or is there some other reason for the gap?

The difference is the corrector. But (a) no diffraction spikes, and (b) the closed OTA means the optics will be good for a very long time - 10-20 years, possibly 30+.


Edited by luxo II, 12 August 2021 - 08:00 AM.

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#17 Maks343

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Posted 12 August 2021 - 05:02 PM

I meant to ask if AT makes a Mak?  I should've been more accurate with my word choice.

 

The SW comes with 2" components whereas the others seem to all be 1.25".  Is there an advantage to 2" with a Mak?



#18 RajG

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Posted 12 August 2021 - 05:57 PM

AT used to sell an AT-branded Mak, the AT6M, but have discontinued it. It was made by Bosma, and likely the same design as the IOptron Mak that is still available.

 

A 2 in diagonal will permit wider views using 2 in eyepieces but there will likely be some vignetting which may or may not be noticeable. Due to their focal length, Maks are really not wide field instruments, and for high-power planetary views you would use1.25in eyepieces anyway.


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#19 Maks343

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Posted 13 August 2021 - 07:44 AM

So aside from the 2" diagonal, the Skymax 150 and the Meade LX85 6" are essentially equal?



#20 luxo II

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Posted 13 August 2021 - 07:59 AM

Is there an advantage to 2" with a Mak?

Yes, some can usefully handle 2" eyepieces - the Intes 6" maks have a 2" back and no issues with filling a big 2" low-power eyepiece such as my 38mm SWA, LVW42, or others similar.

 

Having a 2" back also opens the door to virtually all the bits & bobs for imaging - note that for example the ZWO ASI cameras all have 2" extension tubes and 48mm threads for pretty much everything - OAG, filter wheels, you'll want a 2" 0.5X reducer for DSO, and a 2" Barlow for planets. 

 

While the accessories supplied with the ASI533MC Pro (I have one) include a 1.25" nosepiece which is fine if you're just putting it on in the place of an eyepiece, the snag with that is most of the other bits & bobs available are all 2". Even extension tubes - 1.25" ones are hard to find.

 

Lastly, as all of my scopes have 2" backs the hex turret loaded with eyepieces fits all of them.


Edited by luxo II, 13 August 2021 - 08:18 AM.


#21 Freezout

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Posted 13 August 2021 - 10:39 AM

If you want something light and easy to carry, be aware that the mak 150mm is still quite heavy and require a good mount. Equatorial mounts like cg5 are quickly cumbersome when travel is needed. I ended up taking an AltAZ mount.

#22 macdonjh

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Posted 13 August 2021 - 11:23 AM

For a beginner my recommendation would be the Maksutov Cassegrain because as has been said it is unlikely to need collimation. The views the all three scopes listed will be similar. Once you have some experience and have decided if you are a hobbyist and not a casual observer, you'll know if you can put up with more finicky designs or if you want to stay with something like a Maksutov or refractor.
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#23 RajG

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Posted 13 August 2021 - 04:17 PM

So aside from the 2" diagonal, the Skymax 150 and the Meade LX85 6" are essentially equal?

Yes



#24 Maks343

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Posted 13 August 2021 - 06:01 PM

If the 6" Mak weighs 13-14 lbs and the CG4 is rated for 20 lbs shouldn't that combo work since I'm only using it for visual, not attaching cameras?



#25 jkmccarthy

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Posted 13 August 2021 - 08:50 PM

>  Maks343, on 13 Aug 2021 - 05:44 AM, said:

>  So aside from the 2" diagonal, the Skymax 150 and the Meade LX85 6" are essentially equal?

 

Yes

It's not clear to me that the Meade 6" Mak-Cass is currently available new ... does anyone know?  (If no, follow-on question is whether it's simply out of stock, or has it been discontinued ?)

 

Meanwhile in addition to the aforementioned "Meade, Celestron, Orion & Skywatcher" Maks (all f/12 and made by Synta), there are also 6" Maks sold by Explore Scientific and Bresser (both f/12.5 and made by JOC).  One significant difference is that the ES and Bresser MC-152 model Maks have the primary mirror fixed and focus using an external rack-and-pinion focuser, whereas the Synta Maks piston the primary mirror forward and backward (using a knob extending from the rear of the scope on one side) to focus.  The latter approach is often accompanied by a (small, or sometimes not-so-small) sideways shift of the image in the eyepiece when one changes from clockwise to counter-clockwise (or vice-versa) rotation of the focus knob, because the focus knob internally only acts from one side, causing a slight (or sometimes not-so-slight) change in tilt of the primary mirror when reversing direction of the focus knob.  But I do not know if either of the JOC-made Mak-Cass 152mm OTAs are currently available to purchase new from stock anywhere.

 

And just to avoid misleading anyone, let me also note that the ES and Bresser 127mm Mak-Cass telescopes use the typical mirror piston knob for focusing.  The fixed primary and external rack-and-pinion focuser is unique to the MC 152mm, at least within the ES and Bresser lines.

 

I believe the Meade 6" Mak-Cass has a "mirror locking knob" that can be used to clamp the primary mirror in place, in cases where the user has added some other focusing mechanism onto the back of the telescope, but I don't believe the other companies (Celestron, Orion, or Skywatcher) selling 6" Mak OTAs with Synta-made optics have included this feature.

 

Hope this helps,

 

       -- Jim


Edited by jkmccarthy, 13 August 2021 - 08:55 PM.

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