Orpington Astronomical Society

Astronomy => Astrophotography => Topic started by: Ian on Feb 06, 2008, 12:50:45

Title: which filters?
Post by: Ian on Feb 06, 2008, 12:50:45
Ok, it's Astrofest and I'm thinking about getting some filters.

I'm sure I'll end up with both, but in the mean time, should I get an LRGB set or a Ha and OIII filter for narrowband imaging? They'd both be about the same money...

Bearing in mind I'll be imaging from Sidcup more than Tuesnoad whatdya reckon?
Title: Re: which filters?
Post by: Mike on Feb 06, 2008, 13:01:57
Ha and OIII
Title: Re: which filters?
Post by: Ian on Feb 06, 2008, 13:48:44
are you sure Mike? You seem uncertain...
Title: Re: which filters?
Post by: JohnP on Feb 06, 2008, 14:05:12
disagree - I would say Astronomik LRGB Type II (do you already have a Ha?) Wouldn't exposures be a lot longer with the narrowband as they let less light through which means guiding/ polar alignment etc. etc. all needs to be that  better...

John
Title: Re: which filters?
Post by: Mike on Feb 06, 2008, 15:16:36
Yes, but would mean he can do both narrowband and RGB images as you can do RGB with Ha, O3 and S2. Also, cuts out the light pollution, which is bad from Sidcup. I use my Ha far more than my RGB.
Title: Re: which filters?
Post by: Rocket Pooch on Feb 06, 2008, 22:41:37
yer but you only use Ha because you image emission nebula.....


lets throw this in, Baader LRGB & Ha, OIII these are cheap probably £180 for the lot.



Title: Re: which filters?
Post by: Ian on Feb 06, 2008, 23:57:28
got to watch those baader lrgb filter sets. They don't have a built in ir block according to Adam Hinds, and I'd struggle to fit a separate one into my current imaging setup.

I might have a chat with Atik, see if they do an IR blocking window for the artemis...
Title: Re: which filters?
Post by: JohnP on Feb 07, 2008, 09:34:12
QuoteYes, but would mean he can do both narrowband and RGB images as you can do RGB with Ha, O3 and S2. Also, cuts out the light pollution, which is bad from Sidcup. I use my Ha far more than my RGB.

Mike, Have you done any full colour Ha, O3, S2 images..? I'd be interested in seeing comparison with regular LRGB type images to see if effort involved with extra exposure is worth it. I can only see HaRGB images from you on the gallery... Do you have any issues with colour balance etc. when doing Ha, O3, S2

Cheers,  John.
Title: Re: which filters?
Post by: Mike on Feb 07, 2008, 09:54:19
Yeah i've done a few Ha, O3 and S3 images. They are on the forum somewhere. I will root them out and post them up.

You do need slightly longer exposures, but for a crappy night with bad transparency the narrowband filters cut through the mog allowing you get to get better resutls than you would if you tried the LRGB.

Colour balance is purely down to personal interpretation anyway.