UHC or O-III filter??

[queeniejo]

Hi all,

I have trawled the forum for tips on choosing a filter to observe nebulas, I really am very undecided. I have a 150p dob and am still very amateur at the moment, I have returned after an 8 year absence so am almost back to square one again. My husband will tell me to buy the cheapest or not bother 😂 but I want is best for my needs and my scopes capabilities. 
 

I am very keen to start my stargazing adventures once more, and spend money I can’t afford on accessories. You guys here are definitely the best in helping me decide how I spend my money x

[RT65CB-SWL]

I use both the Explore Scientific UHC & O-lll as they mid-range price wise... and the Baader Planetarium neodymium.

[John]

With deep sky filters I've found that it pays to buy good quality. To me today that says Astronomik or Tele Vue Bandmate II. In a 6 inch scope the UHC is more versatile but the O-III has more impact on the targets that it's strong on. Lumicon filters can also be excellent but there has been variation in recent production runs. The Omega DGM NBP is a really effective UHC type but no UK vendors as far as I know.

You will probably want both types in due course.

I have owned a few less expensive ones but they just didn't seem as effective I'm afraid

Edited October 16, 2020 by John

[jock1958]

Hi there

I have a 2" UHC Televue Bandmate & 1.25" O-III Lumicon filters. From my experience the O-III works best on likes of the Veil nebula and a UHC on other targets like the Dumbbell Nebula (M27), Orion Nebula (M42)  & a variety of Planetry Nebula.

Televue, Astronomic & Lumicon are expensive but probably the best and cheaper filters by Castell & Baader have had good reviews. If you keep an eye out on SGL or UK ABS you could pick up a good second hand one like I did.

Have a read of David Knisley's in depth filter review below.

http://www.prairieastronomyclub.org/filter-performance-comparisons-for-some-common-nebulae/

 

Edited October 16, 2020 by jock1958

[niallk]

O-III

Then... UHC 😆

[Paul73]

Definitely OIII first. It is rare that I use my UHC.

Paul

[queeniejo]

Thank you everyone, I appreciate your help. Ultimately I think I need both 🤣 hurry up payday 

Jo x

[LukeSkywatcher]

Both.

[cathalferris]

I'm actually the other way around for the advice. I got a UHC first, then an OIII. I based that decision on the knowledge that if I could only get one filter, I'd get the one that would give the best improvement on the most objects, and the Lumicon UHC fits that bill for me. I later got a Lumicon OIII secondhand at a really cheap price as it was degraded at the edge but pristine in the middle. The OIII definitely does give a darker background than the UHC, but I've preferred the view and the colouration in the UHC. I've also now got a H-Beta filter, but haven't used it that much.

I found that UHC in a smaller scope gave more useful views, precisely as it dimmed the stars that bit less, and the OIII filter I had allowed a fair bit of red through to the eye. Then again my OIII filter is a degraded Lumicon that has the "rust" so it is fairly obvious that it's not performing at best. Still works very well, but better at small exit pupils <2mm as the degradation is only around the perimeter of the filter - hence why I still use it and have not consigned it to the scrapheap.

[Knighty2112]

On 17/10/2020 at 11:07, queeniejo said:

Thank you everyone, I appreciate your help. Ultimately I think I need both 🤣 hurry up payday 

Jo x

Yes, we all say that too. Astronomy sure does seem to suck that money out of your account! 🧐

[cathalferris]

12 minutes ago, Knighty2112 said:

Yes, we all say that too. Astronomy sure does seem to suck that money out of your account! 🧐

Yeah... Why did I have to pick such capital-intensive hobbies.. Mountain bike (XC/DH), kayaking, astronomy, PC gaming - and a new Covid hobby of Amateur Radio..

The ham radio stuff is nifty, and I've been licensed for only 3 months. But it can be a money sink as well.. A cheap good antenna is ~€500 (I got a Folding Antennas hexbeam, as well as a DX Commander, and an Aerial-51 807-HD, all antennas for different things), and 50m of very high quality coaxial cable like Messi&Paolini Hyperlex-10 to feed that antenna is €170 *for the cable alone*; and a proper high-end solidstate amplifier such as an SPE-Expert with 1.5kW (!!) output is near €5000.. and the radios themselves (new) vary between €500 and €10000.

I'm also waiting for payday

Edited October 19, 2020 by cathalferris

[Waddensky]

I'm with @cathalferris on this one. If you take a look at the link @jock1958 provided, you'll see that the UHC is a good all-round filter and that the OIII is a bit more specialised (but performs really well on a number of objects - the Veil for example).

Just make sure you get a real narrowband UHC filter like the Lumicon or the DGM NPB. Filters like the Baader UHC-S are broadband filters.

[MarsG76]

Both are great for viewing nebulae, but personally (if I'd only be getting one filter) than I'd be getting the UHC filter.

I own the 2" Astronomic and a 1.25" Lumicon UHC as well as both the 1.25" & 2" Celestron OIII filters and the UHC filters are used much more than the OIII, simply because I get much nicer views of nebulae through it than when comparing the view through the OIII filter.

[John]

The Celestron O-III is the same item as the Baader O-III. Both have very narrow band pass widths. Too narrow for my taste even with the 12 inch dob.

The band widths of the various brands are important and will impact the experience that the observer has.

There are not a lot of choices that give really effective band pass widths IMHO.

 

 

 

Edited October 19, 2020 by John

[niallk]

I've Astronomik filters - 4 of them.  They deliver good views - imho 

I must get a 2" filter slide - my uhc might see more use.  I  had a 1.25" filter wheel for my 10" and it really unlocked the use of filters due to pure convenience. 

Edited October 19, 2020 by niallk

[markse68]

I’ve got a baader uhc which is quite nice and useful but do all uhc’s do the red/blue shift thing with bright objects or would it be worth investing in an Astronomik or other?

Mark

[John]

1 hour ago, markse68 said:

... do all uhc’s do the red/blue shift thing with bright objects...

 

I've noticed this effect with stars when using a number of brands of UHC and O-III filters. It seems less obvious with Astronomik filters to me.

 

[markse68]

6 hours ago, John said:

I've noticed this effect with stars when using a number of brands of UHC and O-III filters. It seems less obvious with Astronomik filters to me.

 

Good to know- thanks John

[Tim]

To some extent it can depend on the filter itself. My oringinal Lumicon filters in these bandwidths are both nice, but the UHC offers a brighter, sharper view with better contrast on pretty much every nebula I have tried it on.

If it helps, I have a practically unused 2" Baader Oiii filter in perfect condition for sale in the classifieds, or message me :)

Tim

[jetstream]

On 16/10/2020 at 11:31, queeniejo said:

I have a 150p dob

Just curious- what eyepiece are you going to use with the filter?

[queeniejo]

3 hours ago, jetstream said:

Just curious- what eyepiece are you going to use with the filter?

Not sure yet, probably have to spend more money on that too I guess 😂 

[John]

The effectiveness of these filters is influenced quite a lot by the diameter of the exit pupil that the scope / eyepiece combination generates so eyepiece choice is quite important.

 

Edited October 20, 2020 by John

[queeniejo]

13 minutes ago, John said:

The effectiveness of these filters is influenced quite a lot by the diameter of the exit pupil that the scope / eyepiece combination generates so eyepiece choice is quite important.

 

Oh no now I’ll need suggestions for an eyepiece, to complement a filter I haven’t decided on ...let alone bought. And I now need to pay for them with money I haven’t earned yet. 

[jetstream]

47 minutes ago, queeniejo said:

I’ll need suggestions for an eyepiece,

Yes, thats why I asked actually. I think we should draw from @John experience to find a cost effective 32mm-34mm eyepiece. Suggestions John? hows the Panaview 32mm at f8 for filtered/ widefield use?

I think going straight for a 2" Astronomik or new Televue OIII is the way to go, spend the money here and find a nice cost effective eyepiece.

Btw queenie you have an excellent telescope, nicknamed "APO killers" for a reason.

[Mark at Beaufort]

Hello @queeniejoI assume your 6" Dob is the Skywatcher which is nearly f/8. The decision on eyepieces and filters has a lot to do with your budget. I know many members will recommend high level EPs and filters and although they provide great views I have used less expensive products and have been satisfied with their performance. In saying that I have a Skywatcher 150p which is f/5 and is very good so similar to your scope.

Although I own a TeleVue Nebustar Type 2 and Astronomik O-III filters I also rate the Castell O-III which has a wider bandwidth and provides great views of many of the best nebulae - Veil, M42, M27 etc - here is a link - https://www.365astronomy.com/Castell-OIII-Deepsky-Filter-for-2-Inch-Eyepieces.html

I also agree with Gerry @jetstreamabout the 32mm Panaview in your scope you will have an exit pupil of 4.14 which is okay for your needs.