Best objects through a UHC filter?

[Robbos30]

I've been a visual observer for a while now and have used an OIII filter 99.99% of the time for diffuse/bright nebula.I have a 1.25 inch UHC filter i rarely use and would be interested in some feed back on the type of objects /nebula etc which respond to this type of filter. I have a sirus nebula filter which i think is similar to a UHC.Does anyone else have one of these and what is your experience on its effectiveness?:help:
Cheers Peter.

[Argonavis]

The best person I know to answer this question is Glen C. Hopefully he will respond with a more comprehesive reply than mine.

The only use for an OIII filter is on planetary nebs, and is most useful for faint planetary nebs. It does bring out detail in the eta carina nebula, but almost all bright emission nebula respond much better to a UHC filter.

The UHC filters have wider bandwidth transmission pass than the OIII, so some faint extended objects, like Barnards Loop (naked i) which are virtually invisible in an OIII while explode with detail in a UHC. The UHC filter is probably your first and most useful filter to buy. As the UHC also transmitts OIII, they are also useful for planetary nebs. If you don't believe me, try it on planetary neb NGC 2438 on the northern edge of M46. I can't discern any difference between an OIII and UHC.

M42 the Orion nebula has a high enough surface brightness that filters don't really matter, but a UHC will bring out some of the fainter wisps.

What objects /nebula etc which respond to a UHC filter? M8, M16, M17, ngc6888 crescent, Rosette, Tarantula, Veil, California neb, Vela SNR, the various emission nebs like ngc2626 in Vela, NGC2023 in Orion, bright RCW objects (RCW86, 108). Basically, all bright emission nebula. I have found the improvement stunning, and I can thank Glen C for recommending them to me.
From areas with more skyglow, the OIII would probably be the filter of choice, but from dark skies, the UHC is it.

I do not have any experience with the sirus nebula filter. It is claimed that the filters have a wider transmission than the narrowband O-III but not as wide as the UHC. With a large aperature scope and dark skies they probably perfrom similarily to OIII filters IMO.

[Argonavis]

some good references for this is

http://www.cloudynights.com/item.php?item_id=387

and

http://www.cloudynights.com/item.php?item_id=63&pr=2x9x42

[glenc]

I prefer a UHC filter to an OIII filter. I have both and rarely use the OIII.
It blocks out too much light in my opinion.

The cloudynights.com list is better than any comparison I can give.

If you look under IIS, Images and Photography, Deep Sky, you will find a list of nebulae that respond to both a UHC filter and an OIII filter.
http://www.iceinspace.com.au/forum/showthread.php?t=12896

It comes from the RCW catalogue.
http://cdsweb.u-strasbg.fr/viz-bin/VizieR?-source=VII/216

[Striker]

No doubt.

I have done some imaging with both the OIII and UHC filter and the winner is UHC 10 fold.

[Argonavis]

An very experienced observer in our club was looking at buying an OIII in addition to their UHC, but after 1 night using an OIII filter on loan decided that the OIII is not worth the money.

interesting

[Zubenel]

Thanks Glenc for that amazing tour you gave me at Astrofest. I think it was the highlight for this years event . And on the first night I was there!!!. Can't remember if I ended up with that list of Southern Bright Neb . I suspect it would be a good resourse for rebbos30 , for that matter me aswell. Cheers Zubenel:thumbsup:

[glenc]

Thanks Wes. I am trying to rank the neb by brightness. See
http://www.iceinspace.com.au/forum/showthread.php?t=12713&highlight=nebulae+brightness

The list of 300 DSO is attached. It covers the whole sky and includes Messier objects.
It is a tab-delimited text file, use MS Excel to open it.

Tried to see the Scl Dwarf Gxy tonight but the moon was a problem, then it got foggy. I know where it is now and will try again later.

[Robbos30]

Many thanks guys for your valued responses.My computer died shortly after i posted this thread and only now have become up and running again.I've had a look at the suggested reading sites and am finding it terrific reference and help.Many thanks to you all again.Once the weather clears i'le post the results of my results of my these observations and give you my feedback or better still come to Rons place in the upcoming months and tell me yourself.
Clear Skys,Peter.

[janoskiss]

Try the Veil. It's beautiful through my DGM NBP, which is not exactly a UHC but similar.

[Zubenel]

You will be made very aware that the Veil is Pete's FAV. I love it in mw 10"f5 with that fantastic fov with my astronomic UHC. :D :thumbsup: :bowdown: :eyepop: Cheers Zub

[Don Pensack]

If you'd like to be more scientific about it, try this site:
http://oit.williams.edu/nebulae/browse.cfm
and select the planetary nebula you want to view.
Each nebula has a spectrum showing the emission lines for that nebula.
If the predominant emission is the two O-III lines at 496 and 501nm, then use an O-III filter. The narrower the bandwidth, the better.
If there is significant emission at the 486nm line of H-Beta, then use a UHC filter (or UltraBlock or NPB).
If there is also significant emission at H-Alpha (656nm), then an older UHC filter with the H-Alpha "leak" is preferred, or a newer filter with the H-Alpha broadcast.

Here's a link to a thread on another forum with links to sites that test filters and show which frequencies they transmit:
http://www.cloudynights.com/ubbthreads/showflat.php?Cat=0&Board=beginners&Number=651806&fpart=1&PHPSESSID=

[glenc]

Thanks for that Don.

[ausastronomer]

I have an Astronomiks UHC and OIII in addition to a 2" DGM NPB. The DGM NPB is sold as a narrowband filter but in reality it has a very narrow passband and is a hybrid between an OIII and a UHC IMO.

Whilst I agree that the UHC filter gets the most use it isn't by very much and I am often only using a 10" scope. On a good number of targets the OIII does just as well as the UHC and on many targets I prefer the view with the OIII. In a lot of cases whilst the view in the OIII is dimmer than the UHC it sometimes has slightly better contrast and can show more detail. In Robbo's 30" I would think the OIII would see more use than the UHC but I believe there is plenty of room for both. Certainly some targets respond better to a UHC and vice versa.

Some of the targets that I like to use the OIII on include, keeping in mind the UHC also works well on some of these:-

NGC 2070 (Tarantula)
NGC 1360 (Planetary in Fornax)
NGC 6992/5 (Veil)
NGC 246 (Planetary in Cetus)
M8 (Lagoon)
NGC 2467 (Thors Helmut)
NGC 3242 (Ghost of Jupiter)
NGC 7293 (Helix)
M17 (Swan)

These are just a few targets on which I prefer to use the OIII, there are lots of others. It comes down in many cases to personal preference as in a lot of cases the UHC and OIII will show slightly different complimentary detail.

There is certainly plenty of room for both, particularly with a 30" scope.

CS-John B

[Rodstar]

Thanks for the input, guys.

I have been using an OIII filter for the past 18 months, and I don't have a UHC filter. I find the OIII considerably improves the view of most emission and planetary nebulae. I was, just two nights ago, admiring the Swan (M17) with OIII filter. The Eta Carina area explodes with an OIII filter.

Having said all of that, my interest is now sparked to do some comparison work at my next observing session where someone has a UHC filter: John??