OIII filters and their uses...

[Craig.a.c]

I am going to buy an OIII filter for myself at christmas time to have better views of nebules. Will an OIII filter also give better views of galaxies or just nebula?

Cheers - Craig.

[Tandum]

Craig,
Your OII filter cuts out a bucket load of visual light so it will knock out loads of light pollution as well as visible light from galaxies. If your looking to kill light pollution you;d be better off with some sort of CLS filter. A CLS filter will pass OIII and Hb in the visible band as well as upper red band Ha and sulphur.

I attached a couple of responce curves from astronomiks. The grey curve is human visible. These sort of filters are also known as deep sky, sky light, LPS and a few other names by different makers. They are designed to reduce light pollution.

[edit]
Nothing can substitute a dark site :(

[Bassnut]

In addition to Robins post. NB filters dont suit Galaxys, they are broadband scorces. Good for emission nebs tho. The CLS filters are better for both.

[Starkler]

OIII and narrow band filters work on nebulae as they are designed only pass wavelengths of light most strongly emitted by nebulae, whilst filtering out other wavelengths.

As Bassnut says, galaxies and stars are wide band light sources and narrowband filters are of no help.

[ausastronomer]

Hi Craig,

I own the Astronimks OIII and UHC filters and the DGM optics NPB filter.

If you only plan to buy one filter the DGM NPB may be your best choice. It isn't expensive and works on a wider range of targets than the UHC and OIII filters individually. It is a very narrow pass band UHC filter and essentially is almost a hybrid UHC/OIII filter. It is also idealy suited to a scope of 12" aperture.

http://www.omegafiltersebuyer.com/servlet/the-NPB-Filters/Categories

http://www.cloudynights.com/item.php?item_id=1578

Cheers,
John B

[wavelandscott]

Good advice! I agree with John's comments as to the differences between them...I think highly of my DGM NPB filter...

[erick]

I also agree on the DGM NPB filter - marvellous on Carina Nebula.

I have an OIII filter but have yet to get the opportunity to try it on the primary targets I have in mind - planetary nebulae.

[Craig.a.c]

Thanks for the advice everyone. I knew this place had more to offer then just great pictures.

[Rodstar]

An OIII filter can make a remarkable difference to the visibility of planetary nebulae, and this has always been my primary use for it. Bear in mind that it will interfere with the colour and brightness of surrounding stars....the Astronomiks one renders stars a dim green.