Filter types and varying performance

[bomberbaz]

I have been looking at the range of filters available from different providers and been researching into performance to help me decide which is good for what. (link)

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

However when you look at their performance curves this varies tremendously between differing manufacturers. (see link for some examples)

http://www.astrosurf.com/buil/filters/curves.htm

I was looking into a deep sky filter to perhaps help in viewing some DSO's from my back garden which is heavily light polluted. But given the variance in filters I wonder if some filters are basically doing the same as each other.

An example is Castell who market a filter of theirs as a UHC Deepsky filter. There is also a comparison in the graphs (link) between a Lumicon deep Sky and Astronimik UHC which look quite similar.

So now I am questioning if a deep sky filter is even required for my scope and if i am simply better sticking with my skywatcher UHC and Baader UHC-S which according to the graphs has a similar curve to the astronomik and less than the lumicon.

I have used both the two filters i already have and found the Baader does let through more light overall, so maybe I am just convincing myself as I write this that I don't actually need a deep sky at all.

Any thoughts!!

Steve

[rwilkey]

Hiya Steve, I prefer to use filters for various viewing of nebulae, some cannot be seen without; but I think it would be a good idea to get out and use them a bit more before you make a rash judgement about all filters. The Baader UHC-S is not a very good comparison example, but if you can get a OIII filter sometime you will see a difference in what they reveal, often the difference is subtle, but better on some targets than others. get more practice on different targets, using them with and without to appreciate the difference they make. I would have thought the Baader UHC-S would not be that helpful with a 12" scope.

[faulksy]

hi steve, my view on filters (no pun intended) is this if I use a uhc filter at home it does help bring out more detail due to some light pollution, but when I go to a proper dark site I find things are not as good with filter, so the contrast filter does just that darkening the back ground, but reading reviews on here a 0iii filter is a must for some objects, a good example is swamp thing steve told me from a dark site which we share you can see the north American nebula unaided just by putting the 0iii filter to your eye, that's how good they are. hope this helps

[faulksy]

Hiya Steve, I prefer to use filters for various viewing of nebulae, some cannot be seen without; but I think it would be a good idea to get out and use them a bit more before you make a rash judgement about all filters. The Baader UHC-S is not a very good comparison example, but if you can get a OIII filter sometime you will see a difference in what they reveal, often the difference is subtle, but better on some targets than others. get more practice on different targets, using them with and without to appreciate the difference they make. I would have thought the Baader UHC-S would not be that helpful with a 12" scope.

hi robin you have my attention, why do you think the uhc wouldn't be very good with a 12" scope ?

[rwilkey]

Hi Faulksy, the UHC will be fine with a 12" scope, but I was speaking about the UHC-S in particular, my guess was that the waveband would be a little bit wide to be of use on such a large light-gathering scope, only guessing as I do not own a 12", just an 8" as in my signature below. Narrowing the band down makes for more intrinsic detail and definition in my view on the right targets.

[faulksy]

hi robin again, I have the baader uhc s so is this the wrong type for visual. didn't no there was any difference between the uhc and the uhc,s thanks

[John]

The UHC-S is designed to allow a wider band pass width which makes it effective with small aperture scopes where a "standard" band width UHC might be too severe. With the light gathering capacity of a 12" a full UHC is more effective on enhancing the contrast of DSO's and an O-III even more so with a number of objects.

Bear in mind that these filters really only work on nebulae though, particularly planetary nebulae and supernova remnants.

There is some variation in band pass widths in UHC and O-III filters as you have found and it's worth checking out the data available for the different brands of filters so you know how they compare.

For the past couple of years I've been happy to stick with a single narrowband filter - the Astronomik 2" O-III. This filter is of excellent optical quality and has a band pass width that, for me, balances significant contrast enhancement of the objects I like to use it on with the ability to be used effectively in even my 102mm refractor. This filter makes a huge difference to the views of the Veil and Owl Nebulae - they go from being on the edge of invisibility to quite spectacular objects. Worth the price of the filter just for those two objects in my view

[faulksy]

thanks john, and sorry to spam bomberbaz, I can see the owl nebula from my garden without a filter, but no sign at all of the veil, is the baader uhc,s wrong for my 9.25 , but obviously I need a oiii filter as well. also steve swampthing said it was te veil he could see unaided just the filter.

[bomberbaz]

Blimey when you compare the different bandwidths between the four 0-III filters in the comparison they are all so different. I have to say i would have thought there would have been more uniformity than that but there you go. Apples are not always Apples in this case.

[bomberbaz]

thanks john, and sorry to spam bomberbaz,

Aye get off my thread faulksy hehe

[cs1cjc]

hi robin again, I have the baader uhc s so is this the wrong type for visual. didn't no there was any difference between the uhc and the uhc,s thanks

The UHC-S works just fine for me and has given really good views of in particular the veil, which is albut invisible from my site without it. The curves on the Astrosurf site are very instructive.

[faulksy]

Aye get off my thread faulksy hehe

ok

[bomberbaz]

I did do a comparison on the ring nebula but the conditions were poor so it wasn't a fair one. I will try again and make some notes as to to what the results are and I shall also try to get the dumbell in it and see what comparisons I can make with that one as well..

[John]

I prefer the views of the Ring and the Dumbell, and most other brighter nebula, without a filter to be honest, even with my smaller aperture scopes.

M97 is really enhanced with the O-III but you loose the nice galaxy M108 which lies in the same FoV in a low power eyepiece. So for that one I observe filterless to catch the pairing and add the O-III to examine the contrast variations across the face of the Owl Nebula.

[Stargazer_00]

Has anyone drawn up a list of target objects which work best in ither O-III or UHC? I currently have a UHC filter but rarely use it as I've yet to really get into nebulas beyond Orion's. seen a few of the messier ones in Ursa Major for instance and the UHC did allow them to show where previously they were close to invisible.

I occasionally put in the baader moon and skyglow filter and on occasion it does work at the expense of taking the orange out and putting in a blue in it's place. I figure I might need a 2" one of these as my higher mag eyepieces dont suffer so much with the orange glow and the 1.25" filter doesn't work on the 2" eyepieces which suffer with their larger exit pupil and wider TFOV

[John]

This article is often linked to but it is well worth a read:

http://www.prairieastronomyclub.org/resources/by-dave-knisely/filter-performance-comparisons-for-some-common-nebulae/

[bomberbaz]

I have been looking at the range of filters available from different providers and been researching into performance to help me decide which is good for what. (link)

http://www.cloudynig...tem_id=1520#top

However when you look at their performance curves this varies tremendously between differing manufacturers. (see link for some examples)

http://www.astrosurf...ters/curves.htm

I was looking into a deep sky filter to perhaps help in viewing some DSO's from my back garden which is heavily light polluted. But given the variance in filters I wonder if some filters are basically doing the same as each other.

An example is Castell who market a filter of theirs as a UHC Deepsky filter. There is also a comparison in the graphs (link) between a Lumicon deep Sky and Astronimik UHC which look quite similar.

So now I am questioning if a deep sky filter is even required for my scope and if i am simply better sticking with my skywatcher UHC and Baader UHC-S which according to the graphs has a similar curve to the astronomik and less than the lumicon.

I have used both the two filters i already have and found the Baader does let through more light overall, so maybe I am just convincing myself as I write this that I don't actually need a deep sky at all.

Any thoughts!!

Steve

Try the link above also from my opening post stargazer

[Moonshane]

I have a Castell Oiii and UHC and use the former more than the latter. In fact I really only use the UHC for M42 as it's simply awesome with that particular object and worth the cost alone.

[faulksy]

This article is often linked to but it is well worth a read:

http://www.prairieas...common-nebulae/

only had a bit of a read, nead some time to read it properly, thanks john

[rory]

I found the lumicon uhc a great aid . I managed some nice views of the veil ,even under less favourable sky from my town location. very impressed.

[Scooot]

I used to have a baader uhc s and have now changed it for an astronomic uhc. I find the astronomic much better with my scope.

[swamp thing]

steve swampthing said it was te veil he could see unaided just the filter.

That was the NA neb Mike. Didn't try for the veil. I will try this next time I'm there hopefully it'll still be on show.

[Astrobits]

I have two filters with wide and narrow transmissions ( these are the ones sold by IMAGE OPTICS as their Night Vision filters):

Using these in a light polluted location I found that the UHC performed better than the LPR as it removed more Light pollution.

However, in a less light polluted environment I found that the LPR eliminated the remaining Light pollution and the UHC just made the objects dimmer so was not so useful.

So I would say it depends on where you intend viewing from.

Nigel

[faulksy]

That was the NA neb Mike. Didn't try for the veil. I will try this next time I'm there hopefully it'll still be on show.

I no steve was going to correct it but the time expired so the edit feature disappeared, didn't think anyone would notice

[bomberbaz]

I no steve was going to correct it but the time expired so the edit feature disappeared, didn't think anyone would notice

well we did