Refractor vs Maksutov

[xvariablestarx]

I either read here or on CN, that a 102mm long refractor was roughly equal to a 127mm Mak.

Is this true, and if it is true, is it based on a average quality refractor, or one that costs thousands of dollars?

Does Mak have an advantage over a refractor other than the Maks small physical size?

 

 

[Sunshine]

I have a Mak 150mm, Mak's are a fair bit less expensive than refractors per inch of aperture especially when you get into 4 inch triplets and larger refractors, my 6 inch mak costs less than most 3 inch triplets for example.

I enjoy larger aperture but then again there is a central obstruction (secondary mirror) which does affect contrast as in any SCT, the silver lining is that secondary is smaller than in SCT's therefore offering better contrast than an SCT of comparable size. 

Refractors offer the best contrast (among other benefits like shorter focal lengths for AP and wider fields of view) as they have no central obstruction but are as mentioned,  more expensive to manufacture quality refractors.

Maks are what I like to call the "poor man's large APO" lol, they will offer the closest views possible to a frac of similar size, and cost a good chunk less, I have only given a few examples, others here im sure can expand on what I wrote. I love my Mak, planetary and lunar views are beautiful, yes, they are a niche scope, mainly lunar, planetary, and brighter DSO's, for deep sky not so great.

 

Edited June 24, 2018 by Sunshine
typo's

[Demonperformer]

Not sure, but my guess would be that it is something to do with the central obstruction of the mak (loss of light grasp).

[alan potts]

I bought a 180mm Mak in order to try and take my mind off a 150mm tripet, it didn't really work. I feel over all the contrast from a refractor is better than that from a larger Mak. I have 115mm APO and I have often used them the same night. In this case the Mak shows more as it a good deal larger. I still think Maks are fine scopes but there is just something about a refractor that I just can't put my finger on that still makes me want a larger one than I have. The refractor will most likely win on wide field views too as most Maks are F12 or so, mine is F 15, whereas the refractor is likely to be less than F8, though you can of course get longer ones. My Mak I tend to use for planets more than anything.

Alan 

[RT65CB-SWL]

I love this 'scope more now... than when it had the 'original' Meade backplate...

my 're-modded' ETX105. ? ?

Edited June 26, 2018 by Philip R

[Ben the Ignorant]

4 hours ago, xvariablestarx said:

I either read here or on CN, that a 102mm long refractor was roughly equal to a 127mm Mak.

Is this true, and if it is true, is it based on a average quality refractor, or one that costs thousands of dollars?

Does Mak have an advantage over a refractor other than the Maks small physical size?

 

 

Even a short 102 refractor if it's an apo. Like f/7.

Doesn't relate to price but to physics.

The Mak's advantage is only shortness and weight. Some light is absorbed by the mirrors, some is scattered, some is disturbed by the obstacle in the light path. Tolerances need to be very tight in a Mak, some are very sharp, especially the russian ones (Intes), but an apo that's a bit smaller will be about as bright with better contrast.

[chiltonstar]

Horses and courses, I find. I love the clear views from a frac of planets, doubles etc, but as stated above, they cost a lot more per inch than a Mak and the convenience of a short tube, 180mm Mak is something a frac could not deliver. Fracs are better though when the seeing is poor as the more visible diffraction pattern from the Mak can end up as a bit of a visible jumble, for example around double stars - an issue with any scope with a significant central obstruction.

The resolution of my 127 Mak (it's actually 119 mm clear aperture) is visibly better than the resolution of my 102 mm long tube frac, but in terms of brightness on a DSO like M1, they are about the same because of the obstruction and more optical surfaces of the Mak.

Nowadays, I get the best of both worlds - I put both my 180 Mak and my little ED80 on a SkyTee2.

Chris

Chris

[dweller25]

My Celestron C6 SCT almost matches the planetary views through my 4” Takahashi APO, the APO Views are just a little sharper with more contrast. The APO views are also more stable than in the SCT

My 7” Intes Micro Maksutov gives overall slightly better planetary views than my 5” Takahashi APO but again the views are sharper and more stable in the APO

In my opinion folded telescope designs can give very good results and offer excellent value for money, for me the shorter tube length is more enjoyable to use than with an APO

Refractors do give a very sharp, tight view that is less affected by atmospheric instability than with a scope with a central obstruction

Edited June 24, 2018 by dweller25

[John]

I've owned a few mak-cassegrains but never for very long - the cool down times don't suite my observing too well.

I owned a good Russian 6" F/5.9 maksutov-newtonian for nearly a year alonside an ED120 (4.7") refractor and compared them regularly during that period. The mak-newt's additional aperture gave it a definite edge when viewing deep sky objects but on the planets, the moon and double stars I found very little difference between the two scopes.

After a while I decided to let the Mak-Newt go to a new home because the two scopes were very evenly matched and I could not keep both. I would expect a decent 6" mak-cassegrain to be in a similar league, maybe ?

 

[xvariablestarx]

I may as well tell you the refractor I was interested in, its the Explore Scientific AR102

https://explorescientificusa.com/collections/firstlight/products/fl-ar1021000eq3

 

[John]

1 minute ago, xvariablestarx said:

I may as well tell you the refractor I was interested in, its the Explore Scientific AR102

https://explorescientificusa.com/collections/firstlight/products/fl-ar1021000eq3

 

I think I'd go for a 127mm mak-cassegrain rather than the AR102 in all honesty. If it was a nice ED doublet refractor (eg: Skywatcher ED100) I might swing the other way.

[Red Dwarfer]

8 hours ago, chiltonstar said:

Nowadays, I get the best of both worlds - I put both my 180 Mak and my little ED80 on a SkyTee2.

An underrated little scope - I seen the Cassini division in my ED80 last night with a 4.8 Nagler ?

[chiltonstar]

1 minute ago, Red Dwarfer said:

An underrated little scope - I seen the Cassini division in my ED80 last night with a 4.8 Nagler ?

Indeed yes, mine will show the division all the way round when Saturn is high enough and appropriately tipped. They are lovely scopes for the size and weight! I use a 3.7mm orion EP for planets.

Chris

[25585]

From an eyepiece use POV, refractors can be used with 2 or even 3 inch fit, while Maks are usually restricted to 1.25. 

SCT can have 2 inch adaptors which will vignette certain models. But it's the better than nothing. 

An alternative is a long focal length Newtonian such as a 6 inch F8 , or 8 inch F6 which would have smaller secondary mirrors. Their OTAs would be 4 feet long. Cheapest option for larger aperture lunar & planetary. 

[Alien 13]

If you go on price alone the Mak will win against most long fl achromatic s with a similar objective size (i,e, smaller) but they need a huge mount to perform. You cant compare a Mak with an ED frac at the same price because the frac will be 3-4 times or more the price per mm.

Alan

[xvariablestarx]

Is a Mak on a Goto mount kind of a waste, since it is best on planets, not hard to find DSOs?

edit:

The type of scope I want next, if any depends on how my new camera will work on my Dob; if I can get planetary images that are acceptable to me, then I may not need a new scope, and if I don't then... well that is the reason I post on here about telescopes

If the Dob works I might be content with an ETX 80 to learn where the DSOs are, then aim the Dob at the target.

Edited June 24, 2018 by xvariablestarx

[Ags]

Mak on GoTo makes a lot of sense. They have such narrow FOV it is hard to find faint stuff manually, so GoTo helps. Maks aren't bad on DSOs, my 102 mm Mak is about as bright as my 80mm frac for star clusters and nebulae, and shows very pure star colors too.

[ABQJeff]

Contrast effects (important for planets) largely goes as the linear diameter of central obstruction.  So a 127mm Mak with a 33% obstruction by linear dimension (ie 42 mm) will give contrast of an 85mm ED/APO refractor.  When most people say XX refractor vs YY Mak or SCT on planets, they are generally comparing contrast performance.

Brightness effects (important for DSOs, and in a Mak we are talking planetary nebulas and globular clusters, not widefield DSOs like Veil or North American nebulas) depends on area of obstruction.  The same 33% obstruction in a 127mm Mak by linear diameter will only impact area by 11%, so a 127 mm Mak provides the same brightness as a 120mm ED/APO.

And a Mak 127 is less expensive than 120mm ED doublets (and triplet 85mm APOs for that matter), weigh less, and are shorter (ie easier to mount, travel with, store, etc.)

But Maks also only give narrow fields of view (no sweeping the Milky Way or seeing all of M45).  Also Maks and SCTs require either insulation (what I recommend) or cool down to eliminate thermals interior to the tube.

Current 150mm and larger MCTs now have 2” visual backs, so that helps, but again that will only get you to about 1.5 degrees.  Doing widefield isn’t why you get a Mak.  

Planets, detailed lunar crater views, double stars, planetary nebula, small tight open clusters (eg Wild Duck) and globular clusters are a Mak’s domain, at a fraction of what a refractor would cost to give equal performance on these objects.  You can then take the saved money and get a Rich Field Telescope (small focal length, low magnification telescope, eg ST80, 120ST, ED80) to give you the big open clusters, big nebula and Milky Way sweeping at 3 degrees plus TFOV, that the Mak (or an SCT for that matter) can’t deliver.

 

[StarGazer2000]

This is a typical answer from someone who has never looked through a maksutov and take their "knowledge" from rumours of rumours of rumours of other people who never have either.

No, the linear obstruction "rule"  for contrast effects is not a direct fonction of the linear obstruction, it is much more complicated than that and anyone who has looked through both a mak 127 and a 85mm refractor will laugh their head off at your statements.

Maks are good for everything:  galaxies, nebulas, planetary nebulas, globulars. THE VEILS too (you can still frame  a large part of it in a mak 127 and see it very clearly with fine details).

The vast majority of  DSOs are small or even  tiny, just a few arcminutes in diameter. You actually sound like someone  who is so focused on observing only the bigger targets like M45 and M31 that you don't realize that these are the exceptions...

Put M45 and the couple of very large fields or objects aside, 99% of serious telescopes cannot frame them anyway.

Maks require insulation? What kind of rubbish is that?? ---They require cool down to eliminate thermals interior to the tube--- Ok and other instruments don't?

My 127 mak is ready in 30mn.

So please, ABQjeff,  people like you are a disgrace to the stargazer community, always using the same silly arguments that put  potential mak users off.

[josefk]

Wow @StarGazer2000 - thats a pretty abrasive 1st post here and in fact containing several misconceptions and inaccuracies. Never mind you are commenting a 3-year old thread.

You may want to have a look at a few of the other "which scope/what kit?" type exchanges on here to see that friendly and respectful exchange of different points of view is the order of the day. We definitely DO NOT call other members "a disgrace to the stargazer community". 

Edited August 1, 2023 by josefk

[Stu]

1 hour ago, StarGazer2000 said:

This is a typical answer from someone who has never looked through a maksutov and take their "knowledge" from rumours of rumours of rumours of other people who never have either.

No, the linear obstruction "rule"  for contrast effects is not a direct fonction of the linear obstruction, it is much more complicated than that and anyone who has looked through both a mak 127 and a 85mm refractor will laugh their head off at your statements.

Maks are good for everything:  galaxies, nebulas, planetary nebulas, globulars. THE VEILS too (you can still frame  a large part of it in a mak 127 and see it very clearly with fine details).

The vast majority of  DSOs are small or even  tiny, just a few arcminutes in diameter. You actually sound like someone  who is so focused on observing only the bigger targets like M45 and M31 that you don't realize that these are the exceptions...

Put M45 and the couple of very large fields or objects aside, 99% of serious telescopes cannot frame them anyway.

Maks require insulation? What kind of rubbish is that?? ---They require cool down to eliminate thermals interior to the tube--- Ok and other instruments don't?

My 127 mak is ready in 30mn.

So please, ABQjeff,  people like you are a disgrace to the stargazer community, always using the same silly arguments that put  potential mak users off.

As Josef has said, SGL is not a forum where this kind of attitude is welcomed. It is quite possible to disagree with people’s opinions whilst remaining polite, kind and respectful; that is how we do it on SGL, so please follow suit.