Astronomik clip on filters

[iamzoso60]

I have just stared using my Canon 1100D DSLR camera with my scope. I am not going to get it modded but instead am looking to purchase an Astronomik clip on filter. I shall be using it on deep sky objects and nebula, but from a light polluted garden and was wondering which filter would be the best for me too use?

The one I was thinking of was either the IR -blocker or UV+IR blocker. Would either of these be suitable for my purpose or is there a better one?

[malc-c]

I'm no expert, but I use a Astronomik CLS filter

The Astronomik CLS filter is the right filter to gain the contrast of nearly all objects under light-polluted skies with all sizes of telescopes. Due to the design of the transmission curve the filter reduces the sky background and gas nebulas, planetary nebulas as well as open clusters, globular clusters and galaxies are seen better. The Astronomik CLS blocks the emission of Hg and Na streetlights as well as all Skyglow-lines . All major emission lines from deep-sky objects are passed without surpression. From the research done on emmission lines the most important part of the eye´s night-sesitive region is passed with maximum transmission with our CLS filter..

It works well but can give a blue / green tinge, but this doesn't seem to cause problems when processing. Not cheap at £150 though !

[earth titan]

CLS here. Cuts out the LP brilliantly.

[AndyUK]

I'm no expert either, but I give another vote for the Astronomik CLS filter. It's pretty "aggressive" at blocking out most LP spectra but does indeed give a blue tinge.

The UV block and UV/IR block filters would actually have no effect on LP - UV is below blue wavelength and IR is above red wavelength... but the nasty LP wavelength is (mostly) between red and green (Sodium and Mercury).

However, there are 2 versions of these EOS clip filters - CLS and CLS-CCD. The CLS is NOT IR blocked... but the CCD version is. Here's the transmission curve for the CCD version (I couldn't find the other one!):

http://www.astronomik.com/media/pdf_datasheets/astronomik/cls-ccd_en.pdf

If you're looking at LP filters in this price bracket (and you didn't mind spending a tad more!), the Hutech IDAS LP filter is considered the best in many circles as it doesn't give quite so much of a colour cast as others...

[Earl]

I used to use one (actually tried both), You only need the IR block version if you have had the IR Filter removed off your Camera otherwise it has one built in.

They work OMG Fantastic on the lights in my area I did some test shots and they were astonishing, just taking photos of the street lights themselves.

Edited February 14, 2012 by Earl

[iamzoso60]

Thanks for the info everyone. The CLS version it is then.