Help! Please explain different IDAS Filters!

[Stub Mandrel]

Sorry @FLO but I am not able to untangle the different IDAS filters you sell. Each one seems to claim to be better than all the others.... and not all of them have transmission graphs.

I have Skyglow and 7nm Ha filters. What third filter would you recommend for use with a DSLR? Specifically to tease out more and fainter nebulosity under Bortle 5-ish skies.

OIII?

One of the IDAS nebula filters?

One of the IDAS Light Pollution filters?

Edited September 18, 2019 by Stub Mandrel

[alan potts]

Not cheap are they Neil, I gave up trying to understand any filter a long time back, he says having just ordered a astronomik's UV/IR cut.

Alan

[david_taurus83]

Those STC Duo narrowband filters seem to be quite popular for colour cameras. They pass Oiii and Ha wavelengths. Another new one is the Altair Triband filter which supposedly passes the above and Sii wavelengths.

Trevor on Astrobackyard regularly gives a good "review" of the Optolong L-eNhance filter. Credit to him though, he still regularly uses a DSLR.

 

 

[Stub Mandrel]

So the effect of these is a bit like doing Ha, then (sort of) doing OIII using a  wide-band visual filter and combining them, except you do them at the same time?

Still a bit confused... the Optolong, Altair and IDAS NB2 appear to pass HB, Ha and OIII, but the NB3 only passes Ha and OIII?

Edited September 19, 2019 by Stub Mandrel

[david_taurus83]

7 minutes ago, Stub Mandrel said:

So the effect of these is a bit like doing Ha, then (sort of) doing OIII using a  wide-band visual filter and combining them, except you do them at the same time?

Still a bit confused... the Optolong, Altair and IDAS NB2 appear to pass HB, Ha and OIII, but the NB3 only passes Ha and OIII?

Pretty much! I would say, search on Astrobin with one of the filters as a keyword and see what the images are like.

[Stub Mandrel]

I've gone for the Optolong one, it may have a few percent less pass at the peak frequencies, but it's the only one that really explains what it does with examples - and it appears to do what I want!

[alan potts]

Forgive me for being a bit dim here but would I be able to use one of these filters to improve an image even though I shoot from a very dark area compared to anyone in or near a town. It is something I have been looking at but a 200 quid plus a throw one needs to get it right first time.

Alam

[Stub Mandrel]

Good question Alan! I'm in an area that Clear Outside describes as Bortle 5, but I'm pretty sure it's not as good as that, except straight up.

Last night I got good results using 7nm Ha, butI found that even a basic moon and skyglow filter makes a huge difference to my RGB images so I expect it to work well here.

But... I also expect it to make nebulas 'pop' more if used under good skies - my (limited) understanding is they can be used as a luminance layer with rodinary RGB to get a more accurate colour balance.

[alan potts]

3 hours ago, Stub Mandrel said:

Good question Alan! I'm in an area that Clear Outside describes as Bortle 5, but I'm pretty sure it's not as good as that, except straight up.

Last night I got good results using 7nm Ha, butI found that even a basic moon and skyglow filter makes a huge difference to my RGB images so I expect it to work well here.

But... I also expect it to make nebulas 'pop' more if used under good skies - my (limited) understanding is they can be used as a luminance layer with rodinary RGB to get a more accurate colour balance.

It sure isn't easy from where I am standing to understand any of them. I have a Lumicon (original) deep sky filter. This I bought about 6/7 years ago think it would aid viewing galaxies and the like in my SC and 18 Dob, to some extent it works on them, you can see a difference. This though I later found out was only a fancy name for their CSL filter and as such I don't have any. Whether this will help or improve anything I guess I can screw in place and judge for myself, though with not having a filter wheel it means removing the IR/UV cut filter. I always though Lee filter were expensive for my photography, seeing some of the tags on Astro filters, Lees were free with Cornflakes.

Alan