UHC or O-111 filter fot ST120 ?

[alowen]

On the vendors websites it says the UHC filter is better for smaller aperture scopes and the o-111 is better for scopes 150mm upwards. Is this gospel or do other people have experiences that differ?

It's for my Startravel 120mm.

Thanks

Al

[NGC 1502]

Hi Al. I have both O-111 & UHC, and scopes from 70mm to 250mm.

Personaly, I find the UHC the most useful with any of them. The O-111 does a better job with some objects (the Veil Neb is one of those) but the UHC is more useful more often. The UHC is even useful with my 70mm refractor at times, but the O-111 is too dim with that aperture.

HTH, Ed.

[swamp thing]

Hi

TBH I think this is a case of sick it and see.

Some find the O-III to aggressive in small apertures, others don't.

The UHC does not seem to divide opinion so much.

I would go along to your local society someone is bound to have one you can look through and make your own mind up.

Regards Steve

[damnut]

Hi AlOwen,

Echo comments from swamp thing, I have the st120 as my grab&go. It is a cracking not so little scope. I use 2" throughout so I put up with a little bit of CA on the scope. But I would certainly try before buy as these filters aint cheap!

[MjrTom]

Hi Al

I use both OIII or UHC filters with my 3 inch and 4 inch telescopes and find the UHC is perfect but the OIII is only good on the brighter targets due to light loss.

Looking at M42, Orion Nebula in either filter is quite a sight to behold.

I would say as Steve did, give them a try and see how you get on. If you cant live with the OIII filter you can sell it on the forum for not much loss.

Or borrow a few filters if you are part of an astro society

[John]

I tend to think you would enjoy a good UHC (eg: the Orion Ultrablock) a bit more than an O-III but it's worth trying both if you can. The Baader O-III's in particular are more "severe" so, in my opinion, not so suited to apertures under 8".

My Astronomik O-III works excellently even in my 102mm ED refractor though so there is variation around which is worth researching.

[rwilkey]

I agree with the above, the UHC is the safe bet, to be even safer, the UHC-S is made for smaller apertures, though I have not tried it personally.