OIII 'vs' UHC

[spaceboy]

A recent conversation had me wondering would it really be worth me replacing my damaged UHC filter. For me the OIII filter has alway been found to be the better of the 2 choices but it's always when you need something you find you don't have it.

What would peoples vote be on UHC filters 'vs' OIII filters ?

The reason for buying the UHC filter in the 1st place was an informative comparison between 4 filters by David Knisely on http://www.prairieastronomyclub.org/filtercomparisons.htmwich which seemed to go in favor of the UHC on a good many targets.

Although my 2" filter is damaged it is still in perfect order for use with my 1.25" EP's which the lowest magnification is restricted to x75 and a 1.1' FOV. If it I could save on not having another then all the merrier but I feel I may be restricted to what the UHC can be used on???

As always thank you for any input.

SPACEBOY

[Moonshane]

hi Nick

the link seems wrong, I think this is the one The Prairie Astronomer

I have seen this report myself and read it when making my choice I seem to recall.

it's a great read by an obviously experienced observing and in great conditions.

I think this final point is the important one for my own assessment. he was not in anyway near any light pollution as far as I can tell and for me the darker view of the Oiii seems to combat the effects of LP a bit more and therefore is better for me personally.

don't get me wrong, I am glad I have both UHC and Oiii but it's much more common for me to use the Oiii of the two.

I'll try and do some side by side comparisons sometime in the near future with the 6" and see if I still feel the same.

Maybe I could do:

Dumbbell

Ring

Owl

Veil

and a couple of planetaries I have never seen e.g.

NGC6905

NGC 6543

Cheers

Shane

[John]

Why is it always a competition ?

If my Astronomik was not so versatile I'd have both as Shane does plus something more subtle such as a Neodymium filter. It's good to have as much flexibility as you can and the different types compliment each other rather than compete I feel.

[Stephen]

Again, both

[MartinB]

My experience of using both is that for most nebulae a UHC filter shows more detail since it allows through more emission lines e.g. Ha and Hb. Planetary nebulae have lots of OIII, M27 being a particularly good target for a pure OIII filter but even then I still prefer using my UHC for the Ha that is revealed. I prefer to keep things simple when observing otherwise I tend to spend my time swapping filters and EPs rather than just observing!

[Moonshane]

I do agree with Martin that if you can get away with unfiltered then that's best and what I prefer too.

although, John, I have a Baader Neodymium too (although that's really my moon filter).

maybe I should try that as well as the others if and when I do the comparisons between the filters I have. perhaps I should also try it with M51 currently.

[GazOC]

One strength of the UHC is that it show more in smaller apertures than the OIII because of the extra bandpass.

I've got both and i don't think I use one markedly more than the other but I reckon if I discounted the time i spend looking at Veil though the OIII then the UHC-S would be the "winner". Most of the use I get out of the OIII seems to be on that object.

[spaceboy]

Shane: Thank you for posting the correct link. Regards the Baader Neodymium filter from what I have read there is no comparison between them and the SW LPR filter so I think John is correct in saying this is a subtle deep sky / LPR filter. Never gave it a thought to give my LPR filter a go on the moon.

John: I think it's always a competition as more often than not everything is so expensive some of us have to make the choice between one or the other. On this occasion I agree it is better to have both but having shelled out for a new SW UHC only to find the stupid design meant in my 2" to 1.25" adapter the 1.25" ep's were cutting a perfect circle into the coatings Can't afford to throw money away but do want the versatility. Rock and a hard place.

Martin, Gaz: At what magnifications do you find you most use the UHC filter?

[MartinB]

I mostly use mine with a 12" dob and the magnification depends on the target but typically around x100

[John]

J... the stupid design meant in my 2" to 1.25" adapter the 1.25" ep's were cutting a perfect circle into the coatings .....

Try adding a 14mm Hyperion fine tuning ring to the end of the adapter then put the filters onto that - that will allow clearance for the longest eyepiece barrel.

Hope you have not damaged the filter - the SW UHC's are good filters I've heard.

[spaceboy]

Try adding a 14mm Hyperion fine tuning ring to the end of the adapter then put the filters onto that - that will allow clearance for the longest eyepiece barrel.

Hope you have not damaged the filter - the SW UHC's are good filters I've heard.

Damage done John Will look into one of those rings tho for my other SW filters. Where do you get them from? Felt like complaining to OVL about it but figured it would fall on deaf ears.

[Moonshane]

hi Nick

I see what you mean now.

I think John is referring to these

http://stargazerslounge.com/diy-astronomer/122780-novel-use-baader-fine-tuning-rings.html

FLO sell them for about £7-8.

[spaceboy]

That's it Shane. Feel like such a dumbass not asking for a solution on the lounge earlier but it didn't enter my mind SW would make something that doesn't work correctly with out a separate part. Be it the 2"-1.25" adapter of the filter something sure hasn't been thought out. Put it this way I'm not a happy bunny given £8 would have saved be £70. But such is life.

[Moonshane]

if it makes you feel any better I only thought about this when I put a faint ring on a 2" WO anti violet filter.

I suppose the problem is that different eyepieces have different length noses so they would probably argue they cannot account for all makes.

[spaceboy]

Well that's one Baader ring in the post from FLO. Thanks Shane & John for the heads up just wish I had known sooner but I'm kind of getting used to the bad luck I have so will have to take it on the chin and see if I can some how find the funds to replace the UHC filter.

[John]

Sorry that you have had to suffer the damage Spaceboy

Apparently Tele Vue deliberately don't thread the end of their adaptors to remove the temptation. It's a good place to put filters though so you can swap eyepieces more easily.

[spaceboy]

Thanks John but I only have my ignorance and threading filters in the dark to blame. I had tried them in my extension tube as that is threaded but SW filters just wont let EP's come to focus unless the filter is next to the EP so that didn't work. It's just annoying as I really can't afford mistakes like this. They say with every high there is sure to come a low so this was kind of expected after finding the last EP in my collection.