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Walking on the Moon

Mak-cass advice


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Whether this is the right kind of telescope depends on a number a factors. What are you interested in doing with the scope? If your primary interest is visual observing rather than imaging then it could be a good choice. Particularly if your main interest is in observing things like the Moon, planets, double stars and the brighter smaller deep sky sky objects. I don’t think you would be disappointed with the views through a Mak on the right objects. If you have really dark skies or access to them and that is where you will observe from then a bigger Newtonian reflector will show you more. If you want to image deep sky objects then a shorter focal ratio instrument would be more suitable. This said, I love Maksutovs and currently have two of them, a 90mm and a 150mm. I have other scopes too, however, including a 12 inch Newtonian and 140mm and 71mm refractors so I have all bases covered…

Maksutov Pros: Compact and portable, deliver a long focal length in a small package, deliver very sharp contrasty views, great for objects that stand up well under light polluted skies, work very well for planetary imaging, require no collimation in the Gregory Maksutov type where the secondary mirror is simply an aluminised area on the inside of the front lens. 

Maksutov Cons: Not best suited to wide field low power observing due to high magnification and narrow field of view from their long focal ratio, can take time to cool down when taken outside due to thick meniscus lens at front end, not best suited to deep sky imaging, can attract dew on the front lens (easily fixed with a dew shield). 

 

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What do you currently have?

I have a 4 inch Mak-Cass which has impressed me on planets, yet to really test it on DSOs though. I think Graham covered it fairly well. Maks and SCTs do offer good aperture in a small package, though the ultraportable Dobs have them beaten I reckon and the cooldown undermines grab-and-go potential somewhat. The long f ratio means no widefield but does mean eyepieces won’t show aberrations so much - but if your eyepieces are also being used in fast scopes that’s less help.

I dare say that in terms of *quality* of view a good Mak-Cass might be second only to a good apo refractor? No coma, no diffraction spikes, small central obstruction. But Dobs have raw aperture on their side and diffraction spikes and coma can both be eliminated if you don’t like them.

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I had gotten a 127mm f/15 Maksutov, an ES/Bresser, my very first of the design...

Maksutov5c.jpg.11f53c9b1944c44a42ec3cb9207bd935.jpg

It simulates a 115mm f/16.5 achromat(refractor), yet with the refractor being 190cm in length, over 6'.  Among all reflectors, a Maksutov is the only design that has been described as being refractor-like, regarding the clarity of the views.  Those who favour a long-focus achromat find that they may have their cake and eat it, too, with a Maksutov; much shorter, compact.  Also, with the Maksutov being a reflector, the construction is tighter, and holds its collimation best among same.  Refractors, over all, are the most tightly-constructed, and require virtually no collimation, forever?

A 127mm Maksutov is the sweet-spot among the varying apertures of the design; not too big, not too small, just right.

I see within your signature that you have a 70/300 achromat, at /4.3.  I have one of those, too...

achromat4b.jpg.15bcdb477861c2496d146a9caab0d233.jpg

Most have a go-to mount for their Maksutovs, but I can't use one, as I have far too many trees surrounding me.  So, I will be using that little achromat as a finder-scope instead, and for my own Maksutov...

897346792_beforeafter.jpg.88a5748d4d9e4bb451b95e1abc51c7d6.jpg

I chose a 70mm over a standard 50mm, like a 9x50 optical-finder, as my Maksutov is blind as a bat.  It cannot serve as its own finder, a 59x127, no.  But with the 70mm, I may realise a 9x70 optical-finder, actually 9.4x, with a 32mm Plossl and a star-diagonal.  I knew what was coming, and became resigned to the fact that I would be observing with the Maksutov on manual mounts almost exclusively; for example, on an alt-azimuth...

paper.jpg.1d3ef6298ad9c49b344b67155cec0f9b.jpg

Note the dew-shield jutting out there, of black art-paper, and temporary, yet nigh as long as the telescope itself.  Since, I've gotten a proper one...

1854817417_dewshield8b.jpg.89e7e73b37d91fb325633f7b1dff13a7.jpg

A dew-shield is mandatory, absolutely, without a doubt for a Maksutov, as you don't want the "lens", the meniscus, to get dirty, or as dirty.  It also helps to block natural(the Moon) and artificial (street lights, passing cars) light-sources from entering the telescope, entering the view.

If you're wanting larger than 5", there are solid-tube and collapsible Newtonians and Newtonian-Dobsons at 6" and up. I have a 6" at f/5...

165138073_6f5ab.jpg.32c70b492a9693753c6f8a88d9a5ac21.jpg 

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My current scopes are the Orion goscope iii 70mm refractor and the National Geographic/ bresser NT114CF reflector .  I also have the 50mm/600mm National Geographic / bresser telescope (I seldom use this one but my autistic son has indicated he wants it once the diagonal is fixed) 

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Believe it or not, I have a 50/600 too, but from 1969, a Sears/Towa.  I got it off of eBay for $25, a few years ago.  I restored, enhanced it, then saw a globular-cluster with it...

achromat10.jpg.06af65daedf77558479470d3242db363.jpg

What's wrong with the diagonal?

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Another fan of the Mak 127 here - aperture is big enough to, on the right night, show Jupiter’a bands with some textture, Great Red Spot and watch the Galilean moons and their shadows’ constant dance around the planet.  Saturn shows the rings with Cassini division, shadow of the rings on the planet & vice versa 3 moons and some cloud band features.   On Mars right now the Mak is showing the pole and surface Mare features - amazing! 
The Moon of course shows a wealth of detail and the Mak can give the immersive “Apollo window” effect. 

It’s a very good double star instrument (splits pairs down to around 1 arc second if they are reasonably even in brightness) and on deep sky objects particularly star clusters & the brighter planetary nebulae, and whilst it won’t reveal huge detail on galaxies will show some form in the brighter ones on a good transparent night. 
 

Along with all that the Mak 127 is short, light &  robust enough to be a genuine grab and go option.  I leave mine set up as it’s so easy to be up & running fast. I have a 10” Dob  and various refractors but the Mak remains my most often used scope. 

 

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11 hours ago, Alan64 said:

Believe it or not, I have a 50/600 too, but from 1969, a Sears/Towa.  I got it off of eBay for $25, a few years ago.  I restored, enhanced it, then saw a globular-cluster with it...

achromat10.jpg.06af65daedf77558479470d3242db363.jpg

What's wrong with the diagonal?

Nothing other than the screws for it went missing and I have yet to find them 

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If the 50/600 achromat has a .965" visual-back, a hybrid star-diagonal would be required, in order to use current 1.25" eyepieces...

https://optcorp.com/products/ae-msdh-965inch-to-1-25inch-hybrid-mirror-diagonal, or... 

https://www.ebay.com/itm/234590518632?chn=ps&norover=1&mkevt=1&mkrid=711-117182-37290-0&mkcid=2&mkscid=101&itemid=234590518632&targetid=1263104805286&device=c&mktype=&googleloc=9013737&poi=&campaignid=14859008593&mkgroupid=130497710760&rlsatarget=pla-1263104805286&abcId=9300678&merchantid=8487194&gclid=Cj0KCQiApb2bBhDYARIsAChHC9tJFVKQCsDIvoENdP2mRJZVwR8iF5xUV_q_DEga3K8ByQ6oBuk5Mr4aAqFxEALw_wcB

However, if there are .965" eyepieces on hand to use... https://www.ebay.com/itm/115240816158, or... 

https://www.ebay.com/itm/234476833378?chn=ps&norover=1&mkevt=1&mkrid=711-117182-37290-0&mkcid=2&mkscid=101&itemid=234476833378&targetid=1263104805286&device=c&mktype=&googleloc=9013737&poi=&campaignid=14859008593&mkgroupid=130497710760&rlsatarget=pla-1263104805286&abcId=9300678&merchantid=8487194&gclid=Cj0KCQiApb2bBhDYARIsAChHC9ujMUAIo_VIYi4Tsh87dd6Mq6b4Lh3TQoMO0Q72xWWNQ7UFPf5Z3QwaAgRLEALw_wcB

If the telescope has a current 1.25" visual-back, this star-prism diagonal would serve...

https://telescope-warehouse.com/shop/ols/products/1-14-all-metal-unranded-90-degree-prism-diagonal

If that last one is sold by the time, then this star-mirror diagonal would also serve...

https://www.ebay.com/itm/363772085781?hash=item54b2818615:g:Dk8AAOSwPLFiOPgB

That is, if you can't locate the screws, or replacements for the original diagonal.

Telescope Warehouse, also on eBay as "scopehed1", is owned by Bill Vorce, a respected and well-known vendor in the astronomical community.  I've ordered a few things from them myself.

It would help to see a clear image of the diagonal in question.  Do you have one to post, to share with us?  If not, here's an image of one of my own.  You might then identify the problem for us more clearly...

153385383_diagonalparts.jpg.f913a235b473b82bcbb4f6ba7d70c1c1.jpg

 

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