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Sould I buy a 6" Mak?

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#1 astro42

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Posted 31 December 2019 - 03:37 PM

Would adding a 6" maksutov to my scope collection be redundant given my current line up of scope.

 

8" SCT 2000mm.

4" ED 714 mm refractor.

 

I guess what I'm asking is putting a 6" mak in the mix be a waste of money or would it give me sharper planet views than the SCT and give me the a longer focal length than my refractor.

Kind of a good dedicated planet scope.

 

Or I could be out to lunch and just looking for an excuse to spend more money.crazy.gif

 

 


Edited by astro42, 31 December 2019 - 03:40 PM.


#2 Eddgie

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Posted 31 December 2019 - 03:42 PM

Well, if you buy an very excellent one, then maybe, but if it is just a standard 152mm MCT, it is hard for me to think you will get an improvement on planets.

 

If that is what you are after, I recommend that you spend the money instead on a decent binoviewer and a pair of nice 25mm Plossls or some decent zooms.   These will do more for you planetary observing than a 6" MCT will.

 

Be sure to use the 1.25" diagonal and 2x Barlow that comes with most of the binoveiwers these days for planets, though you don't need the Barlow for other stuff.  

 

If you really want a big bump in planets though, a 10" dob with a good mirror is a fantastic investment. 

 

But if you have not used BVs, this is something that will absolutely improve your planetary performance. 

 

(Excellent MCT would be TEC or Intes Micro.   The other stuff is all going to vary greatly in quality. One might be pretty good, then next one might be barely passable.  If you get TEC or Intes Micro, it will absolutely be very good to excellent every time.  That is what a high price generally gets you in the telescope world, the knowledge that every scope will have high quality optics)

 

When viewing planets, I would rather have a cheap binoviewer and a pair of decent Plossls than the best "planetary" eyepiece ever made.  One of these has worked well for me in improving my planetary viewing results and the other was ho-hum. 


Edited by Eddgie, 31 December 2019 - 03:48 PM.

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#3 Gary Z

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Posted 31 December 2019 - 03:54 PM

Look, I purchased a slightly used 127mm Maksutov this past year.  It frames up nicely with my Canon 600D.  I have had good results for planetary imaging with my C8 for Jupiter and Saturn, but can't wait for July 2020 for these two planetary opposition to take place.  But for lunar imaging, OMG....yes, it makes a difference.  Here's a lunar shot I made this past October.

 

https://www.astrobin.com/nkj5ak

 

Gary



#4 photoracer18

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Posted 31 December 2019 - 04:04 PM

Everybody needs one of every kind of scope if you can afford it. It lets you buy a full set of eyepieces and use them all, not just a couple of them. I have 2 SCTs and 2 MCTs (both USSR made) in my collection.

 

You know you have been in this hobby too long when your equipment list is longer than any message you leave.


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#5 astro42

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Posted 31 December 2019 - 04:11 PM

Everybody needs one of every kind of scope if you can afford it. It lets you buy a full set of eyepieces and use them all, not just a couple of them. I have 2 SCTs and 2 MCTs (both USSR made) in my collection.

 

You know you have been in this hobby too long when your equipment list is longer than any message you leave.

Thanks,

I guess that's a yes!


Edited by astro42, 31 December 2019 - 04:11 PM.


#6 markb

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Posted 31 December 2019 - 04:15 PM

All I can add to Eddgie's comments is that a 6" mak will be tough to cool in a reasonable amount of time, particularly in your northern climate.

 

If you do go to a mak...

 

If you go that route I'd look for a Sital (on the Intes or Intes Micro) or other low expansion mirror. Mine was rough to use in cold weather. 

 

The Intes are, I think, more common than the Intes Micro, and are also very good indeed. I have heard the Intes Micros were slightly superior, but I think it was mechanically, only. The Intes diagonals and other accessories were very well regarded back when they were around. Mine are very high quality.

 

I think most Intes shipped at 1/6 wave and some were 1/8 wave, high strehl, but I am not sure. 1/4 wave were also available, and the figures were not imaginary. The MK67/66 Deluxe may have had the better mirrors? Its been a long time but lots of reviews are still online.

 

They really hold their value on the used market, no surprise there. WTB ads may flush some out.

 

I gave up on getting an etx even remotely close to the same quality, perhaps a hand selected Terabeam, but good luck (and no coatings), Eddgie is right on on the limited selection.

 

The Russian maks have a slightly different thread rear cell pitch which might, but not always, cause issues.

 

The knob focusing versions had virtually no focus shift IIRC. Mine didn't have any I noticed. And don't let the mickey mouse stick on letters on the ota sides scare you off.

 

A last suggestion from the dark recesses of memory, I think the planet-killers of the era were the mak-newts like the MN series with very small central obstructions.

 

Lots of Google results for reviews on such old scopes!

 

+1 on the binoviewers. Wish Baader would pump out some of the new Maxbrights already.


Edited by markb, 31 December 2019 - 04:17 PM.


#7 vtornado

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Posted 31 December 2019 - 04:15 PM

Over the summer I had a lunar/planetary shoot out of 5 inch scopes and a 100mm f/9 ED.

I thought the views were about the same in all.

My 10 inch dob bests them both easily. (sorry I don't have an 8 inch SCT or DOB).

I would assume that your 8 inch SCT would best a 150 MCT, this is based upon all of my 5 inch class scopes

produce about the same image.  (5 inch newt vs 5 inch SCT vs 5 inch MCT vs 4 inch ED).

 

Other intangibles.

The MCT is way easier to mount than the f/9 100mm.  TW1 or porta holds it, 100 f9 was to shaky to focus

accurately with theses mounts.  The refractor rides well on a CG4.

 

MCT has cooling issues.  Some folks wrap it with reflectorix, I have not tried this YET.

MCT has dew/frost issues.  Dew shield is no issue, but a dew strap is expensive and batteries.

MCT is less than half the price of the 100 ED.

 

Given the "scaling" factor, I would assume a 150mm mak is the equivalent of a 120ED for lunar planetary.


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#8 astro42

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Posted 31 December 2019 - 04:46 PM

All that said.

What about a 7" mak instead.

I assume it would give me better planetary views than my 8" SCT?

 

And I'm only looking at the Skywatcher Maks as I don't have the funds for high end optics.


Edited by astro42, 31 December 2019 - 04:48 PM.


#9 sunnyday

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Posted 31 December 2019 - 04:48 PM

Would adding a 6" maksutov to my scope collection be redundant given my current line up of scope.

 

8" SCT 2000mm.

4" ED 714 mm refractor.

 

I guess what I'm asking is putting a 6" mak in the mix be a waste of money or would it give me sharper planet views than the SCT and give me the a longer focal length than my refractor.

Kind of a good dedicated planet scope.

 

Or I could be out to lunch and just looking for an excuse to spend more money.crazy.gif

no relation whatsoever to your question, but what is your 4 inch 714 mm refractor.?



#10 astro42

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Posted 31 December 2019 - 04:50 PM

 

 

It's an AT 102ED.

From Astronomics.


Edited by astro42, 31 December 2019 - 04:53 PM.

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#11 sunnyday

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Posted 31 December 2019 - 04:53 PM

It's an AT 102ED.

i ordered the lunt 102 ed 714 mm I think it's the same
it serves you well?



#12 astro42

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Posted 31 December 2019 - 04:54 PM

Yes I think they are much the same.

It's a nice refractor with little to no CA.


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#13 Cali

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Posted 31 December 2019 - 04:56 PM

 

If that is what you are after, I recommend that you spend the money instead on a decent binoviewer and a pair of nice 25mm Plossls or some decent zooms.   These will do more for you planetary observing than a 6" MCT will.

 

 

Yeah, this one.

 

- Cal


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#14 Gary Z

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Posted 31 December 2019 - 04:59 PM

All that said.

What about a 7" mak instead.

I assume it would give me better planetary views than my 8" SCT?

 

And I'm only looking at the Skywatcher Maks as I don't have the funds for high end optics.

One thing that might be worth noting....the Celestron 7 inch Mak will work with the electric focuser Celestron sells....

As for views over your SCT. I will go with a resounding yes.  Even my 127mm Mak gives me better views.  

 

Also, although not very well documented, my Celestron F/6.3 corector/focal reducer will work with my 127 Maksutov....

 

Since you are looking/interested in Maks, do note the much narrow field of view vs your 8 inch SCT.

 

Gary



#15 astro42

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Posted 31 December 2019 - 05:02 PM

Thanks Gary,

So your 5" mak gives you better planetary views compared to your 8" Sct?



#16 vtornado

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Posted 31 December 2019 - 05:34 PM

Has the SCT been collimated?  Those results shock me.

 

One thing the MCT has going for it, it really holds collimation well. 

My SCT loses collimation if handles moderately roughly, like bumpy car trip, shoved into a knap sack etc.

If handled carefully, I don't have to touch it.



#17 luxo II

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Posted 31 December 2019 - 05:51 PM

A while ago I picked up an intes M615 to use as a travelscope as it’s small enough to pass as cabin luggage even on a small plane, whereas your current scopes won’t (the refractor is too long and the 8” SCT too fat). And it’s easily better than a 4” unless you want really wide fields.

A 7” F/15 mak may well outresolve 8” SCTs but you may have to do some work to find an excellent one. A few years ago I had a SW 180mm example that was optically perfect, and a good friend did a lot of swapping to find the best 8” bar none - and finally settled on an M715D which easily outperformed numerous SCTs in the moon and planets.

The standard intes models were indeed 1/6 wave and the deluxe (D) versions 1/8 wave.

Edited by luxo II, 31 December 2019 - 07:04 PM.

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#18 izar187

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Posted 01 January 2020 - 06:34 PM

Would adding a 6" maksutov to my scope collection be redundant given my current line up of scope.

 

8" SCT 2000mm.

4" ED 714 mm refractor.

 

I guess what I'm asking is putting a 6" mak in the mix be a waste of money or would it give me sharper planet views than the SCT and give me the a longer focal length than my refractor.

Kind of a good dedicated planet scope.

 

Or I could be out to lunch and just looking for an excuse to spend more money.crazy.gif

Tweak the 8".

Correct cooling and collimation issues.

Bino-viewer sounds neat too.

While I do not own an 8"sct, I've seen just beautiful planets in them, dead centered with their tracking, for hours.

And they out resolve 6" newts, unless the 8" sct is not cooled.



#19 izar187

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Posted 01 January 2020 - 06:42 PM

Over the summer I had a lunar/planetary shoot out of 5 inch scopes and a 100mm f/9 ED.

I thought the views were about the same in all.

My 10 inch dob bests them both easily. (sorry I don't have an 8 inch SCT or DOB).

I would assume that your 8 inch SCT would best a 150 MCT, this is based upon all of my 5 inch class scopes

produce about the same image.  (5 inch newt vs 5 inch SCT vs 5 inch MCT vs 4 inch ED).

 

Other intangibles.

The MCT is way easier to mount than the f/9 100mm.  TW1 or porta holds it, 100 f9 was to shaky to focus

accurately with theses mounts.  The refractor rides well on a CG4.

 

MCT has cooling issues.  Some folks wrap it with reflectorix, I have not tried this YET.

MCT has dew/frost issues.  Dew shield is no issue, but a dew strap is expensive and batteries.

MCT is less than half the price of the 100 ED.

 

Given the "scaling" factor, I would assume a 150mm mak is the equivalent of a 120ED for lunar planetary.

How would the 6" f/8 compare to those four?



#20 luxo II

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Posted 01 January 2020 - 08:23 PM

Sorry to say this but you’re spreading FUD regarding the 6”MCT.

The solutions for cooling (insulation) and dew (dwwcaps) are well known and trivial and for a 6” are simply not an issue at al.
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#21 vtornado

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Posted 01 January 2020 - 09:28 PM

Sorry to spread FUD, I thought that was a yank term lol.  I have read about reflectorix, but have not had the chance to try it yet. 

Some folks don't want to mess with their scopes, they are strickly hands off, weird but true.

I am not in that camp, I'm game to try just about anything.

 

I see you are in Sydney, how cold does it get there?

My scopes have to work down to 20F typically in winter, or sometimes down to 0F.

 

Anyhow,  I have tested my 6 inch f/8 newt against the 5 inch group and it is slightly better for planetary.

I say this looking for low contrast details in Jupiter's belts.

It is a lot bigger physically, it doesn't fit in my car if the car is also packed with kids, sleeping bags, fishing poles ...

 

Also should be noted, I have not gone through a bunch of scopes cherry picking the best.

These are all a sample of one.  They are all synta or gso.

 I don't own any lemons, but I may own fair to good scopes on the quality spectrum.


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#22 luxo II

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Posted 02 January 2020 - 12:30 AM

Hmm.. scopes 6" and below I'd expect to be immune to temperature/cooling issues. Dewing depends very much on the relative humidity and the specific microclimate at the observing site.

 

For mass-produced scopes from GSO/Synta/Skywatcher/Celestron/Meade...these are nothing special and are entirely replaceable, do what you like to these and don't think about it.

 

When the scope is collectible (any of the unicorns with premium optics) - keeping the scope in original condition should be very carefully considered vs making any modifications. Even if a modification is made, consider making it reversible. The unicorns include Maks from Intes, Santel, AP, TEC and APM/Matthias Wirth. A modification done poorly will seriously degrade the resale value.

 

Things that matter in this respect are dust/dirty interior of the OTA; loss of the original test report (Intes/StellarOptical), no serial number; test report serial number does not match that on the scope; missing the original accessories supplied with the scope including bag/box, finderscope, diagonal/eyepieces; attempts to add flocking (a total no-no); signs of disassembly (people futzing with the focussing mechanism and breaking it); signs the corrector has been removed/replaced without understanding how this should be done; careless attempts at "cleaning" (scratches or degrading the coatings); mechanical mods that require the OTA to be drilled/opened such as the addition of handles, curved blocks, finder brackets or new dovetails; missing or broken collimation screws for the primary/secondary (downright careless)...

 

While yes I am in Sydney I use 4 observing sites - two in suburbia and two in the mountains 2h drive west.

 

The suburban sites are essentially coastal and while the temperature won't drop below 8C (winter) / 10C (summer), dew is always issue as these have grassed dark soils which are watered and nighttime humidity is high, typically 90% or more.

 

The mountain sites are on inland mountain plateaus at 1100m altitude; the temps can drop to -6C (winter)/11C (summer) however these are in dry sandstone, with pale sandy soils that do not hold water and very little vegetation so dew is rarely an issue. Despite dropping below 0C I have never seen frost/ice at these sites in 45 years; nighttime humidity is usually below 40%.

 

It is well worth understanding the microclimate of your site and if possible choosing a good one vs a poor one, this significantly influences (a) the seeing and (b) dew. Many noobs do not understand this and think any spot is much the same as another; not true.


Edited by luxo II, 02 January 2020 - 01:19 AM.

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#23 elwaine

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Posted 02 January 2020 - 01:52 AM

All that said.

What about a 7" mak instead.

I assume it would give me better planetary views than my 8" SCT?

 

And I'm only looking at the Skywatcher Maks as I don't have the funds for high end optics.

Will a good 7” MCT be better on the planets than a good 8” SCT? Your question is predicated on comparing average commercial grade telescopes of different optical designs. And that “average parameter” is a wild card, - You pays yo money and you takes yo chances.

 

I’ve owned both Maks and SCTs (see below). Relying on memory and not from side by side comparisons, my guess is, that IF the optical quality of the 8” SCT is equal to the optical quality of the 7” MCT, and both are thermally stabile and well collimated, it would be difficult to tell which scope offered up the best planetary views. It will be close. On the other hand, if you take Eddgie’s suggestion and buy a binoviewer instead of a Mak, the improvement in views -regardless of whether your 8” SCT is average or very good - will be quite noticible and will not require side by side comparisons to see the difference. 

 

As for cooling problems with small to medium sized SCTs and MAKs, that is a thing of the past if the OTA is insulated. (I’m speaking from experience and not basing that statement on something I’ve read about.) There are many threads on that topic. 
________________
 

Caveat: I’ve owned 2, 8” SCTs (a Meade and a Celestron), a 5” Mak (Meade ETX), a 6” Mak (TEC), a 7” Mak (TEC), and an 8” Mak (Intes-Alter -Deluxe).  When I owned the SCTs, I did not have a Mak to allow me to do side by side comparisons.)


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#24 luxo II

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Posted 02 January 2020 - 02:05 AM

IF the optical quality of the 8” SCT is equal to the optical quality of the 7” MCT, 

Of course that's true, but it is unlikely. Intes guaranteed 1/8 wave P-V for the deluxe models (eg M715D) - there is no "taking chances". Yes they cost more than SCT's - even secondhand.

 

Celestron/Meade do not offer any guarantee at all, and the Russian test lab results show Celestron 8's average ⅓ wave P-V while Meade 8" SCT average ½ wave P-V.

 

"yo takes yo chance", indeed, while it is possible it, you're highly unlikely to find an SCT that matches the resolution of an M715D.


Edited by luxo II, 02 January 2020 - 02:14 AM.

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#25 elwaine

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Posted 02 January 2020 - 09:33 AM

luxo II, I agree with you. But the OP was asking about a Skywatcher 180mm and not about an Intes or TEC He wrote

I'm only looking at the Skywatcher Mak
I was addressing his specific question. Skywatcher does not guarantee the optical quality of their Maks.

 

While I never used a Skywatcher Mak, by all reports they are quite good, especially at their price point. Then again, there are, by reports, many very good SCTs. So I stand by what I wrote. In any case, a binoviewer will improve planetary views more than switching from an SCT to an MCT... and that was my main point. 
 

BTW, Yuri told me he obtained the mirrors for his TEC Maks from Intes.  Doesn’t Mathias Wirth source his mirrors from Intes also?


Edited by elwaine, 02 January 2020 - 09:47 AM.



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