Filters and OIII filter

[Dazzyd]

Hi all

i have a 150PL and I've just been reading a thread on here about using an OIII filter to see nebulae. Looking on FLO it says they are best suited to 8" scopes and above, would an OIII filter still work well on my scope for something like the Veil Nebula? Is the Skywatcher OIII decent quality? Or is the Baader one much better?

Finally, total newbie question because I haven't used filters before, how do they attach to the scope?

Thanks for any help given, it's really really appreciated

[Dazzyd]

Just realised this should be in the Eyepiece Discussion section, could you move it for me please mods? Huge thanks

[scarp15]

Hi

The OIII will slightly dim stars a bit more than say a UHC filter. Both types will provide contrast to reveal structure in nebula such as the Veil, but the UHC might make for a broader all-rounder. For the Veil a dark location with good transparency will be neccessary, in those circumstances, your scope, with a filter I would have thought should be fine on this object.

The filter 2" or 1.25" usually screws onto the barrel of the eyepiece.

[sgazer]

I have the skywatcher OIII and found it fine for imaging. Not tried visual, may be a little too dark in the 150, perhaps a UHC would be better (much wider pass bands)

[umadog]

You will be able to use the OIII in basically any aperture. However, the rule of thumb is that you are restricted to powers below about 7x to 10x per inch. So you will only be able to look at large objects in a small scope. Here's more detail on the issue: http://www.backyard-astro.com/equipment/filters/lumicon.html

[John]

I'd avoid the Baader O-III in a scope less than 8" aperture - it's band pass width is one of the narrowest I've come across (not all O-III's are the same spec). The Astronomik O-III that I've currently got is at the opposite end of the scale and works well even with my 4" refractor. You would think they would all be standard spec but they are not !

UHC filters like the Skywatcher, and the excellent (in my opinion) Orion Ultrablock might be a better bet in a 6" or smaller scope. UHC filters are slightly more versatile than O-III's too.

All the above said, do bear in mind that these filters only have an effect on nebulae. They don't enhance the views of galaxies or star clusters - the opposite if anything.

There are a few objects where they make a really significant difference, eg: the Veil complex, the Owl Nebula etc. In the case of these objects without the filter you can see virtually nothing of them but with it they pop into view - it's quite remarkable

[swamp thing]

Nebula filters are a bit individual again very much like eyepieces. Some like the gentler approach of the UHC others like myself prefer the aggressive O-III, for me personally the more aggressive the O-III the better, but I do most of my nebula observing from dark sky sites. From these it's very easy to get proper dark adaption. This is essential to get the most from your filter.

It may well be a case of try before you buy if poss. Get yourself along to a local get together and have a bash with some and see how you get on.

[cotterless45]

We usually observe from dirty skies and find the gentle touch of the UHC filter.. In astrobaby's review the UHC is much prefered ( and cheaper).

Nick.

[ChrisThePuma]

Hi Dazzyd

Have a look at this thread:

http://stargazerslounge.com/topic/46397-primer-understanding-and-choosing-filters-for-visual-use/

Also - in this thread there are a couple of links to planets or DSO's and which specific filters work best with which.

HTH?

Chris.

[swamp thing]

1343145489[/url'>' post='1585428']

We usually observe from dirty skies and find the gentle touch of the UHC filter.. In astrobaby's review the UHC is much prefered ( and cheaper).

Nick.

Funnily enough I was observing with astrobaby last month, comparing Mels UHC with my O-III on the Veil neb. The O-III was a clear winner in a 5" ED frac. In fact the O-III filter in the 5" ED frac was better than the UHC in my 10" Dob.

Not all objects are going to favour a certain filter this well though. I'm sure Mel is finding a few objects where her UHC can make a comeback .