What type of Nebula filter have i got

[Taff]

Hi all' can anyone help me out.What type of nebula filter do i have' when looking at the glass it gives a silver affect when i bought it was £60.I am just woundering before i buy another type Thanks.Taff

[acey]

Does it say anything round the rim? Could be quite a few things - all nebula filters are designed to reflect and hence eliminate most frequencies of light and that's why they're silvery.

Why are you planning to buy another?

[Taff]

Hi Acey' No there are no markings around the rim.I'm thinking of buying a different filter to help and see different nebs in the night sky.Taff

[Merlin66]

If there's no markings, it's a problem!! Could be anything from a narrow/ broad band LPR to a Hb, or an OIII???????

The only real way of confirming what it might be would be to check it out with the spectroscope, see which bands it passes. I can do this with my Littrow spectroscope. If you're interested drop me a PM

[John]

Hi Taff,

Without any markings on the filter it's going to be really difficult to tell exactly what type it is without doing the sort of technical stuff that Merlin66 suggests.

Another way is to test it out on a number of different objects then report what you see here - we might then be able to figure out the general "family" of filters that it belongs to eg: broadband or narrowband.

If you are looking for another filter, I can recommend the Baader UHC-S which is a narrowband filter - it does help with the views of nebulae and especially planetary nebulae, even in smaller aperture scopes.

John

[Merlin]

Correct me if I'm mistaken, but I'd always thought that for planetaries we use a O111 filter.

[TheThing]

The only real way of confirming what it might be would be to check it out with the spectroscope, see which bands it passes. I can do this with my Littrow spectroscope. If you're interested drop me a PM

Wow, you have a spectroscope? I've always wondered what one looks like. Can you post a picture please? Also, being a luddite here, what do you use it for (apart from telling which filter is which!)??

[Merlin66]

The Baader narrow band focusses on the OIII and a bit of Hbeta; both of which are found in most planetaries ( Also passes Ha - for the other DSO's). So you could say you get cheap Hb/OIII and Ha filters for the price of one!!

[Merlin66]

Spectroscopes come in all shapes and sizes... a bit like telescopes. I've got about six in my "collection" The main one I'm trying to use is a 200mm Littrow with interchangeable gratings and an Atik16ic for images.

General stellar specta is my goal!!

See my construction pages for photo's and details..

http://www.iceinspace.com.au/63-500-0-0-1-0.html

[John]

Correct me if I'm mistaken, but I'd always thought that for planetaries we use a O111 filter.

An OIII is very effective in larger aperture scopes wheras a UHS or UHS-C is not so "severe" so can be used with smaller apertures. Both types of filter enhance the contrast of planetary nebulae.

With an UHS-C I've been able to see the Owl and Veil from my backgarden with an 80mm scope - these objects were totally invisible without the filter.

John

[russ]

Narrowband filters are great addition to the kit bag. Helped no end with M76 and M97, both of which were faint without but bright with. And really boosted M27 and M57.

Would like an OIII though.

[Taff]

Thanks for your help.Taff