Which 3 visual filters?

[emadmoussa]

I'm re-arming myself with filters due to some ridiculous new lighting in my area. Considering the 2" filter wheel has 4 rooms, I'd like 3 filters that cover pretty much most purposes.

I'm thinking: UHC, O-III and ....general use planetary filter.

Any thoughts??

[Naemeth]

Apart from an O-III Filter I wouldn't really bother with any others. If you must though, go for an O-III, UHC and Baader Neodymium Filter.

[John]

Apart from an O-III Filter I wouldn't really bother with any others. If you must though, go for an O-III, UHC and Baader Neodymium Filter.

Yep, that was going to be my response too

[emadmoussa]

But I heard O-III filters make the image much dimmer than the UHC...?

[Pig]

Imad I found this dim effect with the smaller 6" aperture I had, but it works fine with the 9.25 it should be ok in your 11"

[Naemeth]

But I heard O-III filters make the image much dimmer than the UHC...?

It's more important that they filter out most wavelengths and only leave you a few. The reason why O-III is so popular is that it can make some invisible objects visible - this is because all of the other wavelengths of light are cut out leaving only the ones you want to see.

[emadmoussa]

The problem is, like Shaun mentioned, I have only a 4" and 6" refractors only at the moment - 10 or 12" will land in the coming few months - and with small apertures that image gets very dimmed.

[Pig]

Have you thought about getting a Solar filter ? viewing the Sun can be quite consuming  and  4" -- 6"  are very reasonably priced  ( I know this is not anything to do with a filter wheel)

[Mike73]

I also prefer seeing some stars when using a filter so I place UHC filters at the top however I usually swap from a UHC to a OIII when I increase the magnification, planetary nebulas are objects which seem to work very well when using high mags and the OIII.

Have a good read of this for a great comparison of filters.

http://www.cloudynights.com/item.php?item_id=1520

[RikM]

The problem is, like Shaun mentioned, I have only a 4" and 6" refractors only at the moment - 10 or 12" will land in the coming few months - and with small apertures that image gets very dimmed.

That's kind of the point with OIII filters. They dim everything except what you want to see. From my light polluted garden I've seen the Veil and NA nebs with an ST80 and a SKyWatcher OIII.

I guess it is down to personal preference which type of filters you prefer. OIII gives a darker more contrasty image than a UHC but I generally use the UHC from home for extended nebs, because it is difficult to get good dark adaptation with the surrounding LP, so I don't get the true benefit of the OIII. My OIII tends to be reserved for planetaries.

[Stu]

I would suggest a Baader Neodymium which is excellent on Mars and Jupiter, and the moon, plus also as a general light pollution filter. I would also look at a UHC-S which is good for smaller aperture scopes. OIII is obviously great, but I find with small aperture you do need good dark adaptation to get the best out of it. I believe John's skies are significantly better than those we suffer so an OIII probably works better.

If localised LP is a big problem, I would also consider some 'blocking tactics' as with filters you still need good dark adaptation to get the best out of them. Some people create curtains of dark material hung up to block light out, or strategically placed panels to block specific floodlights etc. I believe Cotterless45 may be an expert in this field!!

Cheers,

Stu

[Moonshane]

Apart from an O-III Filter I wouldn't really bother with any others. If you must though, go for an O-III, UHC and Baader Neodymium Filter.

+1

[Moonshane]

But I heard O-III filters make the image much dimmer than the UHC...?

but that's the point of the narrow band filters. they don't make the nebula or whatever brighter, they block increasing numbers of wavelengths which dims the general ambient light. filters don't add, they remove.

[emadmoussa]

Funny enough, I had a UHC-S and it was excellent, and for some stupid reason I sold it. And now with the new lighting system I'm actually regretting selling it.

Sometimes I hang a sheet on the wash line which helps block the ridiculously close street light. My skies would've been a billion times better if it weren't for that stupid street light. They came and painted it earlier this year, which worked for like a month and now the paint it wearing off and the lamp is getting brighter.

[swamp thing]

I'd go with an O-III, a UHC, and H-Beta filters, but then, I seldom observe planets.

[Moonshane]

recently at the peak star party we saw the effect of more filtration. it was so rubbish weather wise one night I decided to try this and shining my (white) torch through the back showed the Baader Neo to be pinkish and the UHC - Oiii - Hbeta to increasingly darker greenish blue.

[Stu]

Don't forget the OP is talking about small scopes here, not 12 or 16". The H beta is most likely to only be useful for one or two specific targets and with larger scopes.

I have a fair amount of experience with OIII filters in a 4" scope and know that under my skies things like the Veil are still invisible with it!! You need dark skies and adapted eyes to see it with a small scope.

In my mind, best to get filters which are useable and enhance objects which are likely to be good targets for those scopes.

Cheers

Stu

[Moonshane]

good point Stu. I have seen the Veil from my house (quite a lot of LP) with a 90mm frac but I was also thinking about larger scopes of course. I can certainly see the Veil from home with my 6" dob with some ease and the Oiii.

[Stu]

Interesting, I certainly can't see it with OIII and 106mm from my house on most nights. Maybe on the clearest, most transparent nights I could suspect the Eastern Veil but not much more.

At some point I will invest in an Astronomik OIII to see if that improves things but I suspect it is more likely to be having Heathrow nearby and plenty of local LP too.

Stu

[Moonshane]

it might also be where the LP is. I am lucky that my garden faces roughly southeast and therefore my view is mainly in this direction. most of the LP is in the west and northwest/north and thus behind my house to my observing point. to the east is the peak district so perhaps my garden is actually better than I thought. also, we are elevated by about 100m ASL so I think this helps.

[Stu]

Sure there is a lot in that. The fact that I am in a area where planes stack and get lined up for landing I'm sure doesn't help! There are rarely fewer than 3 or four planes visible, often overhead so the vapour trails won't be helping transparency. Strangely the noise is rarely an issue, modern planes when just circling or on low throttle are actually pretty quiet!

Stu

[Stu]

Quick update on this.... Just tried the OIII and UHC-S in the TV76 with 21e on the Veil. Skies were not brilliant, but not too bad. With the OIII I could just about detect the Eastern Veil, but the UHC-S did not show it at all. One of those where if I didn't know what I was looking for I would have just gone straight past it. I guess it shows that OIII can be useful in smaller scopes too, although I still think there is a place for the others on brighter nebulae.

Stu

[emadmoussa]

I think that makes the point, Stu.

[Andy_E]

I think the only way to settle the OIII / UHC filter conundrum is to try both. I've found lately that the OIII gets the most use...why.... because I actually don't like the view through either filter, so if I have to use one I'd rather use the one that shows things that I simply can't see without it. Having said that, the UHC can be quite useful on the right objects when the moon is becoming a nuisance.

[John]

I think the only way to settle the OIII / UHC filter conundrum is to try both. I've found lately that the OIII gets the most use...why.... because I actually don't like the view through either filter, so if I have to use one I'd rather use the one that shows things that I simply can't see without it. Having said that, the UHC can be quite useful on the right objects when the moon is becoming a nuisance.

Thats pretty much how I feel about filters too. I seldom use my Astronomik O-III but when I do it's on objects where it's impact is really significant.