127 Mak Question

[M4lcs67]

It may seem a daft question, but since I am new to astronomy I have a question.

Can anyone tell me why Maksutov telescopes only go up to 127mm diameter whereas Schmidt Cassegrains go larger. Would Maks loose their effectiveness if they went any larger?

Just curious really.

[GazK]

They don't stop at 127 - for instance:

150 Mak Pro

But the prices rise exponentially with aperture, which is why the bigger apertures are less common. The reason for this is presumably the same as for bigger refractors; cost of figuring the optics, and in particular (I assume) the corrector plate.

[nightfisher]

maks do go larger, i have a 140mm mak, and skywatcher make them up to 180mm

[GazOC]

As said they do go larger but the thickness of the corrector compared to a SCT is the main reason they are less common in larger sizes.

[Stu]

For my sins, I have an 8" mak :-). It's quite extreme at f20 but is superb on planets, the moon and also fantastic on smaller, brighter dso's like globular clusters and planetary nebulas. It allows you to use long focal length ep's and still get high mags. Eg a 28mm gives x 142.

It's also still quite compact, relatively easy to transport and of course rarely needs collimating.

Cheers

[Macavity]

Weight, cost and cooling time of the corrector. That said, I sometimes feel MAKs were getting a disproportionately bad press. Happily, positive practical experience of users, has overcome much of this...

(With a modest observatory) I can dream, I guess.

http://www.widescreen-centre.co.uk/Products/STF_MIRAGE_8_(1_6)_Maksutov-Ca.html

Not greedy... a mere 1/6 wave might do...

[nightfisher]

For my sins, I have an 8" mak :-). It's quite extreme at f20 but is superb on planets, the moon and also fantastic on smaller, brighter dso's like globular clusters and planetary nebulas. It allows you to use long focal length ep's and still get high mags. Eg a 28mm gives x 142.

It's also still quite compact, relatively easy to transport and of course rarely needs collimating.

Cheers

nice scope stu, the omc 200 is a bit of a rare beast, fancied one myself!

[johninderby]

No......what you really want is one of these.

John

ASTRO-PHYSICS

305mm F12.5 Maksutov Cassegrain

with Carbon Fiber Tube

[GazOC]

nice scope stu, the omc 200 is a bit of a rare beast, fancied one myself!

I've "nearly" bought one of those scopes several times.

[Whippy]

Maksutovs are fairly common up to 6" but as Gaz has mentioned, thinner corrector plates (which makes thermal equalibrium easier) and mass production of SCT's makes them more common in the larger sizes. Saying that, Ian (lunator) managed to split Sirius at SGL6 with his OMC250 and Intes Micro can make them up 16" so it is possible.

Tony..

[M4lcs67]

Thanks guys for clearing that one up for me. I guess the 127's are the most popular due to their reasonable price as well.

[Stu]

Whippy, I think the omc250 and larger scopes don't have a full aperture corrector plate which backs up the comments about the difficulties of making them at larger sizes. I think they have a spider aswell so probably aren't exactly the same as the smaller maks.

Nightfisher, thanks, it is a lovely scope. In good seeing and when cooled properly it gives amazing views - have used x400 a couple of times on Saturn a number of years ago in very good seeing and it was amazing. Will be at PSP in October if you are going.

Cheers

[GazOC]

yep Stu. a lot of the larger Maks have sub aperture correctors.

[swamp thing]

Hi

I remember seeing a 16" Mak in one of the astronomy mags.

Permanent mounting of course but what a tool.

Regards Steve

[Whippy]

Whippy, I think the omc250 and larger scopes don't have a full aperture corrector plate which backs up the comments about the difficulties of making them at larger sizes. I think they have a spider aswell so probably aren't exactly the same as the smaller maks.

Indeed, Ian's OMC 250 does have a sub-apeture corrector although AFAIK, the Intes Micro one's still have a full aperture corrector just like the smaller ones as seen here: Teleskop online Shop , TMB, APO , Dobson , Professionelle Teleskope, Kuppeln , Teleskopabdeckungen , Teleskope , Ferngläser , Teleskope online kaufen , APM Telescopes - Verkauf Beratung Herstellung Alter MN16 APM Spezial Lieferumfang . Of course, mounting such a beast and keeping it at ambient would be fun!

Tony..

[Stu]

Now that is a beast, and a very nice one too :-)

Stu

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