OIII Filters?

[bing434]

Hi guys I haven't done any research into the use of these accessories but I'm lead to believe that they are designed for bringing out nebulae? Can anyone clarify if this is correct and can recommend good 1.25 and 2" filters for my f/6.8 80mm apo.

[John]

OIII's are generally reccommended for 6"-8" of aperture and larger - they are a bit "severe" for an 80mm scope. A UHC might be a better bet - the Orion Ultrablock is pretty effective.

Both types are effective on nebulae, especially planetary nebulae.

[Astro_Baby]

I'd agree - with an OIII on even my 8" newt struggles - they are pretty aggressive filters.

Dont be fooled by the 'photo like views' - they aren't. They just make some nebula a bit more contrasty.

[Keiran]

Ive used one on my 8" Newt, and I found i could have done with more light... It does make them visable abit more... but at the same time it removes alot of light aswell

[weega]

You can use O-III filter on your 80mm, but only at low power.

Usually O-III filter is usable with an exit pupil around 4-5mm.

On a 80mm telescope it means you can use O-III only at about 20x.

20x => veil nebula and few more...

ciao

dan

[gary1968]

I have a OIII filter and used to use it on my C8N. I have only ever seen the Veil Neb. visually with this set up and even then only once. I is very severe cutting a lot of the light out but it was very contrasty.

I aint tried it on my 8" F4 yet but will do next winter.

HTH,

Gary

[riklaunim]

I should get Castell O-III filter this week. It should be broaded than typical O-III - thats how it looks on the spectral charts.

[weega]

I should get Castell O-III filter this week. It should be broaded than typical O-III - thats how it looks on the spectral charts.

Let us know how it works! :-)

I'm very curious to know how do theese "cheap" filters work

I'd like to buy the Omegon UHC filter: his transmission curve is very similar to Orion Ultrablock, but at a third of the price.

ciao

dan

[russ]

Everyone seems to have different mileage with the OIII. Perhaps expectations are too high.

These are two examples of why i consider the OIII an essential part of my kit:

M97 The Owl - with 200P from backgarden. Barely visible without filter. Easily visible with OIII. The downside, without the filter i could just see M108 in the same field as M97 but with the filter M108 vanished.

The Veil - with 12" dob from backgarden. Could just (i mean just) see the veil using averted vision with no filter. With the OIII i couldn't miss it. As Mel says, it's not an astro image view but it is possible to easily track it across the sky.

But here's the real feather in the cap for the OIII. Using a 102 f5 refractor i could not detect the Veil at all without the filter. But with the OIII i could see the Veil easier than with the 12" without the filter.

The OIII is an aquired taste. It is severe and i can understand why others find that unappealing.

[riklaunim]

I'd like to buy the Omegon UHC filter

Omegon in Germany is used to brand SkyWatcher accessories etc. The Omegon Light Pollution Filter, UHC and O-III are those SkyWatcher filters. They even use the same images.

[John]

Everyone seems to have different mileage with the OIII. Perhaps expectations are too high.

These are two examples of why i consider the OIII an essential part of my kit:

M97 The Owl - with 200P from backgarden. Barely visible without filter. Easily visible with OIII. The downside, without the filter i could just see M108 in the same field as M97 but with the filter M108 vanished.

The Veil - with 12" dob from backgarden. Could just (i mean just) see the veil using averted vision with no filter. With the OIII i couldn't miss it. As Mel says, it's not an astro image view but it is possible to easily track it across the sky.

But here's the real feather in the cap for the OIII. Using a 102 f5 refractor i could not detect the Veil at all without the filter. But with the OIII i could see the Veil easier than with the 12" without the filter.

The OIII is an aquired taste. It is severe and i can understand why others find that unappealing.

Great post Russ

That pretty much sums up my feelings as well - I would not be without an OIII although I much prefer the less "severe" band pass width of my Astronomik OIII over the Baader OIII. Because of that I've found the Astronomik fine with use with my 102mm refractor - as Russ says the views of the Veil at low power on a dark night of good transparency are superb - worth the price of the OIII on their own IMHO

[weega]

Omegon in Germany is used to brand SkyWatcher accessories etc. The Omegon Light Pollution Filter, UHC and O-III are those SkyWatcher filters. They even use the same images.

good to know!

now I'm going to surf the web searching for some reviews

thanks

ciao

dan

[russ]

I use the Skywatcher OIII and highly recommend it if you don't want to invest a large sum. You can buy the SW 2" OIII for less than most other 1.25" OIII filters. If you want a filter with a broader range, then i also highly recommend the Orion Ultrablock. Although that filter is not the bargain it used to be.