Ca-K correcting lens test results.

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Valery
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Ca-K correcting lens test results.

Post by Valery » Wed Dec 02, 2015 12:06 pm

Hi all,

Last September I have teseted my new development - a Universal CaK corrector.

Here the results how does it work in such a difficult conditions - in a very fast 100mm F/5 achromat.

Without a corrector I were not able to detect even sign of granulation. Spots, bright regions and
some bright "creeks" without details in them. Also, no solid focus - always feel to refocus again and again.

With the corrector in place the focus is like a sharp edge. Smallest move of the focuser and no longer focus,
no sharp edge details on the screen.

Photos were taken in a slightly different seeing. You can see what the resolution can a fast achromat 100mm F/5
can deliever at 393nm if it is corrected for spherical aberration at this wave length.

Note that SA at 393nm in a 100mm F/5 achromat is about 2,7 Lambda !!! In a 150mm F/5 is is even higher - 4 Lambda!

In a 150mm this corrector work similarly good, just need to be somewhat close to the telescope objective.


If enough peoples will be interested, we can make a small batch of such correctors. The price is about $800 - 900
depends of how many samples will be ordered in a batch.

Click on the images to see them at a full resolution.

Valery
Attachments
09 28 2015 UT 07h 42m 100mm F5 + 393nm corrector.png
09 28 2015 UT 07h 37m 100mm F5 + 393nm corrector.png
09 28 2015 UT 07h 45m 100mm F5 + 393nm corrector.png
Last edited by Valery on Thu Dec 03, 2015 10:09 am, edited 1 time in total.
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marktownley
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Re: Cak correcting lens test results.

Post by marktownley » Wed Dec 02, 2015 3:20 pm

Nice results! All my scopes are running at f10, would it improve things there? What diameter is the lens?
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Valery
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Re: Cak correcting lens test results.

Post by Valery » Wed Dec 02, 2015 3:46 pm

marktownley wrote:Nice results! All my scopes are running at f10, would it improve things there? What diameter is the lens?
I believe that such a correcting lens is useful for larger telescopes with relatively fast and very fast objectives.

A 40mm F/10 really don't need corrector which costs 20x as much.

The entry size for solar CaK telescopes I consider 100mm F/5. Of course, an 80mm F/5 - F/7 will work too, but again
the corrector is too expensive to use it there.

The next is 100mm F/8-10 and all scopes larger than 100mm in aperture.



Valery
"Solar H alpha activity is the most dynamic and compelling thing you can see in a telescope, so spend accordingly." (c) Bob Yoesle.

Largest full size 185 - 356mm Dielectric Energy Rejection Filters (D-ERF) by ARIES Instruments.

Derek Klepp
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Re: Cak correcting lens test results.

Post by Derek Klepp » Thu Dec 03, 2015 7:35 am

Thanks Valery

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