Barlow and refocus your blocking filter?

Frankenscope? Let's see it!***be advised that NOTHING in this forum has been safety tested and you are reading and using these posts at your own peril. blah, blah, blah... dont mess around with your eyesight when it comes to solar astronomy. Use appropriate filtration at all times...
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Valery
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Re: Barlow and refocus your blocking filter?

Post by Valery » Sun Jul 10, 2016 6:43 am

Ghost-Fire wrote:
Valery: Aries Safix solar blocking filters; better strehl, tighter out of band blocking?

Telescope - SAFIX - Barlow Lens - BF - camera.
"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.

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Re: Barlow and refocus your blocking filter?

Post by Merlin66 » Sun Jul 10, 2016 8:26 am

Not sureI understand the question or the rational...
Are you trying to say that the bandwidth of the blocking filter (nominally 10A) would be improved? Or that it could be used as a stand alone Ha filter in some way??
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Re: Barlow and refocus your blocking filter?

Post by christian viladrich » Mon Jul 11, 2016 6:35 pm

As put forward above, the FWHM of a BF is quite large (from 6 to 10 A). The enlargement of the FWHM due the F/D ratio would be rather small, at least as long as we stay higher than say F/15.
The two images from Alexandra are for a single Fabry-Perot or a double stack Fabry-Perot. So, I am not sure if your question is about the position of the BF or the "F-P" ?


So maybe, your initial question was about the position of the F-P
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