Etalon info for beginners

these are all of the great references that our users have shared with others.

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Etalon info for beginners

Post by Solar B » Sat May 16, 2020 8:48 am

Hi Folks

I have been asked for a link to info on etalons in general ... say air spaced v solid or just

a general understanding of bandwidths and how etalons operate.

If anyone can advise on some info on here then that would be great 👍

Would be good for me to read as well 🌞

Thanks .... Brian


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Re: Etalon info for beginners

Post by Solar B » Sat May 16, 2020 9:14 am

Thanks Pedro

I have looked at Christians site before but I don't think it's necessarily for beginners though.

Brian


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Re: Etalon info for beginners

Post by AndiesHandyHandies » Sat May 16, 2020 9:44 am

Hi

The PST shows a whole Sun view with prominences visible.
For visual on Prominences my M180 PST Stage 2 Mod shows brighter more contrasty images than a Daystar Quark I recently bought.
Issue is a small sweet spot and ghosts off the PST etalon, you have to rotate the etalon in the focusser to move away.
Even with a 180mm aperture I get best images with 25mm eyepiece.

The Quark has a circular polarizer in to remove ghost images but it dims the result. Other manufacturers Lunt? do not put in a filter but users complain about the ghosts and lack of light when they fit polarisers.

For a Quark with 4.2x Barlow in I reduced a 102mm F5 Skywatcher/Celestron OTA to be similar to the DS60 OTA Fno 3.5 and fl 350mm and the view improved because of the extra light going through the etalon. Somewhere between the original Quark and my M180 mod for the proms. Detectability is the square of intensity.

Using a little front etalon as an internal etalon inside a bigger OTA modification gets you brighter bigger images but at a cost in terms of the size of a 'sweet spot' for the PST or bandwidth changes across a solid etalon.

Andrew.



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Re: Etalon info for beginners

Post by rsfoto » Sat May 16, 2020 2:48 pm

Solar B wrote:
Sat May 16, 2020 8:48 am
Hi Folks

I have been asked for a link to info on etalons in general ... say air spaced v solid or just

a general understanding of bandwidths and how etalons operate.

If anyone can advise on some info on here then that would be great 👍

Would be good for me to read as well 🌞

Thanks .... Brian
Hi Brian,

Maybe here https://en.wikipedia.org/wiki/Fabry%E2% ... rferometer


regards Rainer

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Re: Etalon info for beginners

Post by Solar B » Sat May 16, 2020 6:05 pm

Many Thanks All

But I'm still looking for something that's perhaps a little less highbrow if possible ?

Brian


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Re: Etalon info for beginners

Post by John » Sat May 16, 2020 7:19 pm




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Re: Etalon info for beginners

Post by Solar B » Sat May 16, 2020 11:30 pm

Thanks John

I had read Colinskis detailed reports before but had long since forgotten about

them 👴

Brian
Last edited by Solar B on Tue May 19, 2020 3:33 pm, edited 1 time in total.


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Re: Etalon info for beginners

Post by marktownley » Sun May 17, 2020 6:43 am

Think I might put this in the reference library when the topic goes quiet, a useful post to start Brian.


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Re: Etalon info for beginners

Post by Merlin66 » Mon May 18, 2020 8:47 am

In my recent book “Imaging Sunlight” - Springer there’re a good chapter on the etalon function and current available solar filters.


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Re: Etalon info for beginners

Post by Bob Yoesle » Mon May 18, 2020 1:28 pm

You might find this CN thread of interest:

https://www.cloudynights.com/topic/4809 ... on-basics/


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Re: Etalon info for beginners

Post by Solar B » Tue May 19, 2020 3:21 pm

https://www.hpb.com/products/imaging-th ... 3319248721

Is this the book Ken ?

And thanks Bob ..... great to hear from you to 👍

Oh and I had long since forgotten about that CN thread also ....... my relatively insignificant thread

has turned into something quite significant to me 🌞

Brian


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