What filter?

[Stargazer_00]

So I want to see Nebulas better (more detail in Orion, any detail in Crab, Dumbell, Witch Head and so on). I view from a dark garden in the middle of a town so I have LP skies but no direct light on me at my viewing site

I have a mixture of 2" and 1.25" eyepieces. I have a meade 5k diagonal in my refractor which I can screw a 2" filter onto the part that goes into the scope, thus allowing all eyepieces regardless of size to benefit from the filter.

I also use a 2" ED barlow without the barlow element permanently in my dob so that all eyepiece sizes get a compression ring fitting. This means that I can screw a 2" filter into the place where the barlow element used to live and again all eyepiece sizes should benefit from the filter.

First question: Does having the filter this far in front of the eyepiece, rather than screwed directly to the eyepiece still work?

Second question: I'm guessing I'd be best off with the O-III filter over the UHC as I intend to get the most use out of it in my 10" and this reports to work better than a UHC in large aperture. Is this the right decision? I will probably end up getting both if they have distinct uses. I currently have a baader neodynium which I use for moon and occasionally planets. Do any of these filters boost galaxy contrast under LP? I also have a Baader Solar Continuum filter. Does that have any use on DSO or is it very much solar only? Neo and Solar are both 1.25" so I may sell these and upgrade to 2" if they work as I intend above.

Third Question: Which is the better filter out of Baader and Skywatcher sold by FLO? I like the packaging on my current Baader filters and there is a comment on the Skywatcher that the filter has been scratched by the packing which seems odd to me. Optical performance has to come first as I can repack if the SW is better.

Thanks

[DirkSteele]

FYI, you mention the Witch Head Nebula in your lists of objects you hope to improve. No filter will improve that object as it is reflection nebula rather than emission nebula which UHC and OIII will improve.

As for your questions, having the filter in the optical path will improve your view and there is a lot to be said for not having to unscrew and re-screw a filter every time you change an EP.

The OIII is a more aggressive filter (narrower band pass and less emission lines) so it can improve the contrast further than UHC but some objects would benefit more from UHC (you can think of UHC being more general purpose and OIII being a bit more specialist). Because the OIII is more aggressive, it allows less light through which is why the conventional wisdom states that larger aperture scopes are needed to use it as the image becomes too dark.

I am unfamiliar with either filter make (I have Thousand Oaks and Lumicon filters) so other SGL members can offer opinions on each brand you mention.

[E621Keith]

...

First question: Does having the filter this far in front of the eyepiece, rather than screwed directly to the eyepiece still work?

Second question: I'm guessing I'd be best off with the O-III filter over the UHC as I intend to get the most use out of it in my 10" and this reports to work better than a UHC in large aperture. Is this the right decision? I will probably end up getting both if they have distinct uses. I currently have a baader neodynium which I use for moon and occasionally planets. Do any of these filters boost galaxy contrast under LP? I also have a Baader Solar Continuum filter. Does that have any use on DSO or is it very much solar only? Neo and Solar are both 1.25" so I may sell these and upgrade to 2" if they work as I intend above.

Third Question: Which is the better filter out of Baader and Skywatcher sold by FLO? I like the packaging on my current Baader filters and there is a comment on the Skywatcher that the filter has been scratched by the packing which seems odd to me. Optical performance has to come first as I can repack if the SW is better.

Thanks

1. Yes. I fit my 2" in front of the diagonal

2. Baader Neodynium and other broadband filters help a little bit for galaxy, they cut some skyglow and sodium line, but not narrow band filter. Galaxies are broadband objects and really need a dark sky.

3. Baader have a better reputation than SW when it comes to filter. Most reviews suggest Neodymium works better than the SW LPR.

[rwilkey]

I have used the Sky Watcher filters and they do the job well, nothing wrong with the packaging and they are quite safely packed ready for use. The packaging is better on the Baader, but not worth paying the extra in my view, in fact they are so well packed they are really fidley to get out in the dark. As with Matthew above, I think the UHC filter is the first one to get, as it is useful on more nebulae, but the OIII is also good for feint objects, the Veil comes to mind etc.

The Baader Solar Continuum Filter is only for solar use, and there are no filters that will help with other DSO's such as galaxies. It's a great idea to buy 2" filters as this will serve you well in the future, and there is no advantage or disadvantage as to which part of the optical trail you add the filter, on the diagonal or on the adaptor, it makes no difference, it will perform just as well either way.

[Stargazer_00]

Thanks so skywatcher uhc you think?Ordered it from flo

[rwilkey]

I have got good use out of the Sky Watchers, but have not used the Baader versions except in other filter types such as the Neodymium, there is no doubt they are good quality, as is Lumicon, which I much prefer to Baader.

[John]

They say get a UHC first and then an O-III later. Personally I just use an O-III although mine (Astronomik) has a generous band pass width so seems to act as a good general purpose filter. On some objects these filters can make the difference between seeing practically nothing and a rather nice view, eg: the Veil and Owl nebulae.

I've use the TS UHC filter which I think is very similar to the Skywatcher UHC, and it seemed to work pretty well. The O-III just adds a little more contrast to certain objects.

[swamp thing]

Personally I don't hold with the "UHC for small scopes, O-III for larger ones" saying. It's more to do with exit pupil than aperture.

Both filters work well in any scope (I often use my O-III with my naked eye to view large nebulae from dark sky sites) .

I find that the problem using an O-III from sites with LP is more, getting proper dark adaption to get the most out of it, as It darkens the sky background quite a lot more than a UHC. A head covering of some kind to block extraneous light may solve this (but you may look a bit daft ).

From an urban sky, I would spend the money on a tank of gas to get to a dark site. If Galaxies and diffuse nebulae are your interest this would be my first port of call. This will have a much more significant effect than any filter from an urban environment. Viewing galaxies and diffuse nebulae from LP locations is never going to be that successful even if you have no light directly on you. Sky glow makes this the sad truth. Get yourself out of town buddy you won't regret it. I always transport my scopes for this very reason.

Clear Skies

[Stargazer_00]

I have a 2 week holiday coming up in deepest darkest norfolk later in the year. Wondering if I should take my st120 or hire a people carrier and take the dob. I'm Worried that the views will be so good I'll never enjoy my garden again.

[swamp thing]

I have a 2 week holiday coming up in deepest darkest norfolk later in the year. Wondering if I should take my st120 or hire a people carrier and take the dob. I'm Worried that the views will be so good I'll never enjoy my garden again.

Easy one......the Dob

It's a decision you won't regret, trust me. Even if we can only get away a few times a year to a really good dark sky it makes it all so worthwhile. It gives me the strength to put up with the London sky glow the rest of the year.

[Stargazer_00]

I completely forgot to check the moon phase for my holiday. .. You can guess already cant you. .

[DirkSteele]

Been there....Booked a holiday to Oman last year which included a stay hundreds of km from any settlement of note in the desert, but unfortunately I found myself waiting till as late as 2-3am for the moon to set. However, once it was gone, I had some of the most memorable observing sessions, using the 4" Apo I had taken, that I have ever had.

[swamp thing]

I completely forgot to check the moon phase for my holiday. .. You can guess already cant you. .

Oh no!

[Stargazer_00]

Full moon on the day I go.... typical. Going To have to wait till I get home to see when it sets

[Dunkster]

After which the moon rises later and later each day until it magically disappears

[Stargazer_00]

I checked actually on stellarium. 4 days into my hoiday the moon doesnt rise till 2300ish so this will actually have little effect other than I'll hopefully have clear nights every night and the first few days ill do lunar and the rest of the holiday ill do DSO No to convince the wife I need to take the dob...

[michael.h.f.wilkinson]

Best of luck. I think my APM branded UHC filter is the same as the Sky-Watcher. I have got some really good results out of that. I use a diagonal with an integrated filter slide (you can get such filter slides for certain dobs too, I gather). Much better than faffing about screwing filters into a diagonal or EP.