Nebula Filters for photography

Hi all,

I do astrophotography with a Canon 300D (Rebel) and a C9.25.

I'm considering buying a narrowband nebula filter (OIII and H beta) - I
already have a broadband LPR. Most of the articles I've seen say that
narrowband filters are not suitable for astrophotography.

Just wondering - it this because of the long exposures needed? But H alpha
filters probably pass less light and they are used for photography - just
have to guide. Or is it because of the colour cast? Surely converting the
picture to monochrome solves this?

Appreciate any experience on this.

Thanks
TG

In message , Tan Thiam Guan
writes

I do astrophotography with a Canon 300D (Rebel) and a C9.25.

I'm considering buying a narrowband nebula filter (OIII and H beta) - I
already have a broadband LPR. Most of the articles I've seen say that
narrowband filters are not suitable for astrophotography.

Just wondering - it this because of the long exposures needed? But H alpha
filters probably pass less light and they are used for photography - just
have to guide. Or is it because of the colour cast? Surely converting the
picture to monochrome solves this?

Appreciate any experience on this.

Actually there is a pretty good reason not to bother with ordinary film
and an OIII filter. The band pass wavelength is essentially the same as
the safelight colour for processing colour film. Ordinary panchromatic
emulsions barely record OIII (that is why film based colour photos of
nebulae are artificially bright turquoise and red - the strong green
OIII line is barely registered by film. CCDs will work OK.

H-alpha works fine with any reasonably red sensitive emulsion.

Regards,
--
Martin Brown

Martin Brown wrote in
news
In message , Tan Thiam Guan
writes

I do astrophotography with a Canon 300D (Rebel) and a C9.25.

I'm considering buying a narrowband nebula filter (OIII and H beta) -

Actually there is a pretty good reason not to bother with ordinary
film and an OIII filter. The band pass wavelength is essentially the

The Rebel 300D is a digital camera

This page is probably one of the most interesting on the topic

http://www.astrosurf.com/buil/d70v10d/eval.htm

See the frequency response graphs towards the end of the article.

(the 300D has the same sensor as the 10D as you know)


--
Pierre Vandevenne - DataRescue sa/nv - www.datarescue.com
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