MAK 90mm for solar

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DSobserver
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MAK 90mm for solar

Post by DSobserver » Tue Sep 15, 2015 10:04 pm

Hi

have you ever try to use a small 90mm MAK + Herschel wedge?

I know that herschel should be only use with refractor, but maybe a 90mm mak wouldn't be that critical...

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Re: MAK 90mm for solar

Post by marktownley » Wed Sep 16, 2015 5:27 am

Might get a bit hot at the secondary?
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Re: MAK 90mm for solar

Post by DSobserver » Wed Sep 23, 2015 10:14 pm

no other point of view?

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Re: MAK 90mm for solar

Post by Merlin66 » Wed Sep 23, 2015 11:04 pm

No, not really.....
The heat on the secondary - which in the case of a Mak is a deposited aluminium disk and not "glued" to the corrector will be <<8W.
Should be minimal risk.
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Re: MAK 90mm for solar

Post by kornfeld » Wed Aug 02, 2017 9:22 pm

Merlin66 wrote:
Wed Sep 23, 2015 11:04 pm
No, not really.....
The heat on the secondary - which in the case of a Mak is a deposited aluminium disk and not "glued" to the corrector will be <<8W.
Should be minimal risk.
How about a quark with a 127mm Mak? I would for sure use an IR blocker at minimum back at the diagonal to shield the quark, but what are people's thoughts about the risk this would pose for the telescope itself?

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Re: MAK 90mm for solar

Post by DJD » Thu Aug 03, 2017 12:39 pm

Wasn't one of the early Quark variants targetted at the Questars, so presumably the combos would work ?
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Re: MAK 90mm for solar

Post by kornfeld » Thu Aug 03, 2017 1:25 pm

I should have been more clear---I'm considering doing this without a full size external ERF, and am curious about the risk this poses for the telescope.

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Re: MAK 90mm for solar

Post by Merlin66 » Thu Aug 03, 2017 3:48 pm

I'd be comfortable recommending just the UV/IR for the 90mm aperture, but not the 125mm without testing.....
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Re: MAK 90mm for solar

Post by kornfeld » Thu Aug 03, 2017 3:58 pm

If you were testing things, how would you go about doing it? I have a lead on a relatively cheap scope, and would be willing to risk it for the data collection. :)

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Re: MAK 90mm for solar

Post by Merlin66 » Thu Aug 03, 2017 4:44 pm

I would set the telescope up, no eyepiece etc. and use a series of aperture spots, 90mm, 100mm,110mm diameter and work my way through them - leaving the telescope tracking the sun for up to five or even ten minutes for each setting.
Checking all the time for obvious signs of energy damage - the secondary, the objective, the eyepiece baffle area etc.
If the tests go OK at full aperture then I'd say you should be OK.
Any questions, let me know.
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Re: MAK 90mm for solar

Post by DSobserver » Fri Aug 04, 2017 6:54 am

one more point : there is many plastic part in mak scope. If for any reason sun is not well centered : expect a melt plastic smell...

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Re: MAK 90mm for solar

Post by Astrograph » Sat Aug 05, 2017 3:57 pm

There is a version of the Combo made for Questar but this was also to be used with a front ERF.

If you have a Maksutov with just a coated spot for the secondary then it will depend on the coating as much as anything else. If the coating is aluminium then it should reflect UV down to about 200nm quite well. If the surface quality is not very good then it will also disperse the UV as opposed to reflect it toward the eyepiece. If it were silver then its reflectivity drops quite fast so at 300nm it just absorbs UV and that might be bad. I guess as this is a budget scope it will be aluminium. Think you should keep an eye on it though (not literally!)

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Re: MAK 90mm for solar

Post by kornfeld » Mon Aug 07, 2017 2:52 am

Sounds good. I'll report back if I end up getting the scope, and we'll see what happens! Thank you for the help, everyone.

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