Telecentric System brand and X for Air-Spaces etalon(PST/Lunt) for Celestron Edge HD 8

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...
Post Reply
User avatar
OlegLviv
Almost There...
Almost There...
Posts: 629
Joined: Mon Sep 13, 2021 4:24 am
Location: Ukraine/Lviv
Has thanked: 881 times
Been thanked: 907 times

Telecentric System brand and X for Air-Spaces etalon(PST/Lunt) for Celestron Edge HD 8

Post by OlegLviv »

Hello friends!
I want to buy Telecentric System for PST and Lunt air-space etalon and dont know X and brand for my Celestron Edge HD 8
I wrote book Solar Astronomy and author say that Air Spaces Etalons need F40 TO F50 for good work etalon :band
In my mind for Celestron Edge HD 8 needs 3.7 (F41) or 4x (F44) for good as for me with 180mm aperture.
3X as for me not good for air-space etalon only f33 :band

What do you say???

Which brand awesome?

Thank you!


https://www.facebook.com/oleg.lavigne/
https://www.astrobin.com/users/RamonLviv/
https://www.astroclub.kiev.ua/forum/ind ... ic=46758.0


Telescope: TS 152/900/Bresser 102/1350
Baader D-ERF 160MM
2xBaader 1.25 GPC
2xLunt 50mm
Lunt Cak B1200
Coronado BF15
Camera: Apollo Max 432M/ Apollo Mini 429M/Player One Mars II 462M/QHY 290MM
Mounh: 2xSky Watcher AZEQ6
Telecentric Lense: Televue Powermate 2/2.5x/4X/5X
User avatar
Bob Yoesle
Almost There...
Almost There...
Posts: 994
Joined: Thu Mar 08, 2012 7:24 pm
Has thanked: 539 times
Been thanked: 807 times

Re: Telecentric System brand and X for Air-Spaces etalon(PST/Lunt) for Celestron Edge HD 8

Post by Bob Yoesle »

Baader TZ4.

But you'll have an 8 meter focal length - do you live on a mountain top with near perfect seeing? You'll also need a 0.5 focal reducer to get down to a 4 meter focal length after the filter... which still is pretty enormous.


Diagonally parked in a parallel universe.

Curiosity is the father of knowledge; uncertainty is the mother of wisdom.

Dark-Sky Defenders
Goldendale Observatory
User avatar
marktownley
Librarian
Librarian
Posts: 42269
Joined: Tue Oct 18, 2011 5:27 pm
Location: Brierley Hills, UK
Has thanked: 20424 times
Been thanked: 10243 times
Contact:

Re: Telecentric System brand and X for Air-Spaces etalon(PST/Lunt) for Celestron Edge HD 8

Post by marktownley »

Also, a telecentric won't work as well as you think with an airspaced etalon.

If you use a donor pst run it in collimated mode using the stock lenses, that will give you a lot more contrast.


Image
http://brierleyhillsolar.blogspot.co.uk/
Solar images, a collection of all the most up to date live solar data on the web, imaging & processing tutorials - please take a look!
christian viladrich
Way More Fun to Share It!!
Way More Fun to Share It!!
Posts: 2150
Joined: Sun Jun 14, 2015 4:46 pm
Location: France
Has thanked: 1 time
Been thanked: 2712 times
Contact:

Re: Telecentric System brand and X for Air-Spaces etalon(PST/Lunt) for Celestron Edge HD 8

Post by christian viladrich »

Hello,

I have run more precise calculations of the effective FWHM of an etalon according to the f-ratio in a telecentric system.

First, the transmission curve of the etalon depending on the f-ratio :
For air-spaced etalon :
http://astrosurf.com/viladrich/astro/in ... imated.jpg
For mica-spaced etalon :
http://astrosurf.com/viladrich/astro/in ... imated.jpg

More interesting the effective FWHM of air-spaced etalon :
Image
and for mica-spaced etalon :
Image

Cheers


Christian Viladrich
Co-author of "Planetary Astronomy"
http://planetary-astronomy.com/
Editor of "Solar Astronomy"
http://www.astronomiesolaire.com/
Post Reply