Orpington Astronomical Society

Astronomy => Technical => Topic started by: The Thing on Nov 28, 2009, 14:40:31

Title: What clip filter for Canon 350d?
Post by: The Thing on Nov 28, 2009, 14:40:31
I have been looking at CLS, Ha with different pass through widths, OIII etc. on Ian Kings site.

If you had to choose one which would it be?

This is primarily for imaging in Beckenham.
Title: Re: What clip filter for Canon 350d?
Post by: Mac on Nov 28, 2009, 17:50:42
If i had to choose one, it would be the New CLS filter.
designed for ccd chips.
As opposed to the old ones.

http://www.astronomik.com/en/astronomik_cls-ccd_filter.html (http://www.astronomik.com/en/astronomik_cls-ccd_filter.html)

slightly higher transmision rates for Ha, Hb ect.




Title: Re: What clip filter for Canon 350d?
Post by: MarkS on Nov 28, 2009, 19:50:44

Yep, I agree with Mac.

If you have to choose one filter go for a CLS.  It will be of use in more situations than the Ha, OIII etc.

Mark
Title: Re: What clip filter for Canon 350d?
Post by: The Thing on Nov 29, 2009, 12:01:22
Thanks guys, CLS new styley it will be.
Title: Re: What clip filter for Canon 350d?
Post by: mickw on Dec 05, 2009, 17:40:02
*Hijack alert*

Why is plain glass (ok not actually plain) being chosen over the Baader option -
http://www.modernastronomy.com/filtersBaader.htm#eosConversionFilter (http://www.modernastronomy.com/filtersBaader.htm#eosConversionFilter)
When you need an IR block filter anyway which costs roughly the same ?
Title: Re: What clip filter for Canon 350d?
Post by: MarkS on Dec 05, 2009, 19:27:41
Quote from: mickw
Why is plain glass being chosen over the Baader option -

My recommendation is to use the Baader conversion filter for two reasons:
1) Focusing will still behave normally - the plain glass causes the CCD to focus at a different point to the viewfinder/auto-focus (unless you add the correct shims to the CCD supports)
2) With plain glass you will need an additional 2" IR/UV filter that generally costs more than the Baader conversion - unless you are using totally reflective optics.

However, the Astronomik CLS-CCD filter does also block IR light (unlike "standard" CLS filters) so that will do the job fine.

Mark
Title: Re: What clip filter for Canon 350d?
Post by: mickw on Dec 05, 2009, 20:10:34
Cheers, Baader conversion it is  :)
Title: Re: What clip filter for Canon 350d?
Post by: The Thing on Dec 05, 2009, 21:11:32
I will be using plain glass and the Astronomik CLS-CCD clip filter.