What filters work for direct observation?

[mikemarotta]

I was impressed by the success of @j.gardavsky in viewing with filters. @notFritzArgelander commented to me that he uses an H-beta himself. I bought one, actually, but then returned it unopened because I thought that I misunderstood their use. Over on CloudyNights, a newbie asked why he could not see anything through his filter and he was informed that they don't work like that. They are for dark skies (at the very least) and astrophotography (most often).

In fact, I bought both an O-III (cancelled order) and a Hydrogen-Beta and was planning on getting an H-alpha, but decided on that as well. (Since they seem to be universally out of stock, it was an easy decision anyway.)

So, what's the story? Can I use filters when observing? (Clearly, that's true.) And--more to the point--what are the parameters?

Thanks!
Mike M.

[KingNothing13]

I cannot answer your question about parameters, as I am mostly in the dark about filters as well, but I can go with what I have experienced thus far - which is not much.

I just picked up some filters from Vixen in their closing sale.

the OIII filter worked great to pickup the Veil Nebula - first time I've been able to see it from my back yard.

I also used the contrast booster to help pull out the dimmer M's in the Virgo Cluster, which I have also never been able observe - but that's mostly due to positioning in the sky against where I can observe from.

I also bought the variable polarizer, but I have yet to use it.

And I just ordered a #82A light blue filter from Agena to use with Saturn and Jupiter this season - they apparently work very well with the planets.

The NPB DGM filter always gets great reviews, and is one that is on my list to pick up.

[notFritzArgelander]

I regularly use the Baader H-β and OIII narrow band filters with an ~8nm bandpass when observing DSOs. I have them in 2" size since I often use low power eyepieces but for convenience I have them in 1.25" format as well when I want higher magnification. This is mostly useful for planetary nebulae since "finding" them often needs a low power eyepiece but looking at detail needs more magnification. I've used them in my SV ED80-A.

Do NOT get the "high speed" versions. These are designed for use with high speed astrographs like f2.

For contrast enhancement I also use the Baader solar continuum filter for lunar/planetary and also the white light viewing of the Sun.

[gregl]

I bought a variable polarizer years ago but find it more trouble than it's worth. One time I was up at 8000 ft. altitude on a night that will live in local observation history with the most stable atmosphere ever seen here. Someone had an 18-inch Obsession and popped in an OIII filter for the Swan Nebula and it was stunning. I tried the OIII in my tiny 8-inch SCT and it did help the Swan. I haven't bought the filter but I have spent time looking at catalog descriptions of large aperture dobs.....

[Ylem]

Even though I have a bunch of filters lying around, I haven't used them in years. If I recall the Olll was the most useful, but only in the 8" scopes.

The coloured ones didn't seem to do much, I tried the yellow on the ST80, thinking it might help with CA, Not.
The Mars filter helped out a bit last year, but only in the 8 again.

I will have to dig them all out tomorrow and see all that I have and give them another chance.

[notFritzArgelander]

Even though I have a bunch of filters lying around, I haven't used them in years. If I recall the Olll was the most useful, but only in the 8" scopes.

The coloured ones didn't seem to do much, I tried the yellow on the ST80, thinking it might help with CA, Not.
The Mars filter helped out a bit last year, but only in the 8 again.

I will have to dig them all out tomorrow and see all that I have and give them another chance.

I have color filters and I no longer use them much. I'm finding the Baader Solar continuum filter is enough. However I haven't given the @j.gardavsky blue filter for galaxy hunting a fair trial. His reasoning for it working is sound.

[j.gardavsky]

Hello Mike,

not-Fritz has already posted above the essentials on the nebular filters, here some add-ons from me.

A good OIII filter is worth of taking as a starter,
especially should you like a deeper view on some of the supernova remnants (like the Veil Nebula), on the Wolf-Rayet nebulae like the Crescent, on the star birth regions, on the Messier nebulae, and on a mass of the planetary nebulae.

The H-Alpha filter does not help much, as the dark adapted vision is as good as blind to the red H-Alpha light.
The wide passband H-Alpha (35nm) has been helpful on Mars during the opposition, but that's another area of the filter applications.

The blue(RGB)CCD interference filters (Astronomik, Baader) are helpful on some galaxies with the spiral arms, and the light yellow filters are helpful on some galaxies with the dark lanes.

I am not frequently using the UHC filter, besides on some galaxies, like the galaxies with the star birth regions, and on some peculiar galaxies.

The narrow passband Solar Continuum filter from Baader is perfectly suited when viewing the Moon, as its wavelength around 545nm is where the refractors achieve their maximum Strehl. And the eyepieces offer their best performance in green, as well.

Clear skies,
JG

[pakarinen]

I have an ancient Lumicon tri-band nebular filter that works as well as can be expected here - 96% OIII 496nm, 91% OIII 501nm, and 94% Hβ. I used it for my one and only sighting of the Veil many years ago. I recently bought an Astronomik, which is subjectively maybe a tad better. Nothing can beat dark skies though.

For lunar, I have a light yellow #7, an orange #-something-or-other, a green "moon filter" and an Orion 13% neutral density. I find I use the yellow more than anything else, followed by the green. The orange is too deep for my tastes and there's something about the Orion that I don't like.

[mikemarotta]

Thanks to all. My interest was (is) in the O-iii and H-beta.

I have the Celestron lens-and-filter kit and have used the color filters to some advantage. I was fairly aggressive with them when I started, but I tapered off. I last used them to reduce the glare from Venus and perceive the phase.

When I come around to this again, I will be judicious in my selections and ask again here before I commit to the choices.
(Not to put too fine a point on it, but as a contractor, I take on a lot of different kinds of assignments and right now I am working for half of what I was getting in April. It was a great opportunity to research and write about photonics, but it came at a cost. So, the indulgences will have to wait for the next contract.)

I went back through CN and also SGL looking for the original post that changed my mind. What I found on both this time was lots of people making good use of their filters. I did not find that other one. But it was my own fault for as often as I have warned others not to be misinformed by the cognitive dissonance of experts with opinions. I mean -- nothing personal here and now -- but some TransGalactic ranked user with 5000 posts and 9000 hearts is just someone without a life. They could know a lot. But you have to take it with a grain of salt. Myself I look for consensus. And on these boards, this one and the others, you do not get a lot of argument back and forth. I believe that the sociology works in favor of the first opinion.

That all being as it may, also, I was looking to use the H-alpha with the solar filters to view and photograph the Sun. I understand now that that will not work.

So, again, thanks to all.
Best Regards,
Mike M.

[Bigzmey]

Lots of good advices already. I should add that the quality of filters is of most importance. Cheap filters introduce light scatter which degrades performance. My trusted brands are Lumicon, Astronomik and Baader.

I add my vote for OIII and Hbeta filters. I also never leave home without Baader Moon and Sky Glow and Baader Contrast Booster filters. I use them as planetary filters for Jupiter, Saturn and Mars. I also use Baader Moon and Sky Glow as light pollution filter to pull galaxies, globular clusters and comets from light domes. The effect is subtle, but often makes difference between seeing faint smudge and not seeing anything at all.

[j.gardavsky]

Lots of good advices already. I should add that the quality of filters is of most importance. Cheap filters introduce light scatter which degrades performance. My trusted brands are Lumicon, Astronomik and Baader.

I add my vote for OIII and Hbeta filters. I also never leave home without Baader Moon and Sky Glow and Baader Contrast Booster filters. I use them as planetary filters for Jupiter, Saturn and Mars. I also use Baader Moon and Sky Glow as light pollution filter to pull galaxies, globular clusters and comets from light domes. The effect is subtle, but often makes difference between seeing faint smudge and not seeing anything at all.

Yes,
it is difficult to explain why the Baader Moon and Sky Glow filter sometimes works on some galaxies.
Having a pair of these filters, unexpectedly, I have been able to see some condensations in the M66 galaxy in Leo through the 25x100 binoculars.

There is also an ongoing discussion about observing the galaxies from the backyard through the filters in
https://www.cloudynights.com/topic/7650 ... ry11043864

There are more things in Heaven, than are dreamed of in the popular filter lists,

JG

PS: Sorry for borrowing from Shakespeare

[Ylem]

Dug my filters out, besides the Mars, Moon and coloured ones, I have 2 Lumicons, the Olll and a Deep Sky.

I'll have to play around when the smoke clears.

[Bigzmey]

Lots of good advices already. I should add that the quality of filters is of most importance. Cheap filters introduce light scatter which degrades performance. My trusted brands are Lumicon, Astronomik and Baader.

I add my vote for OIII and Hbeta filters. I also never leave home without Baader Moon and Sky Glow and Baader Contrast Booster filters. I use them as planetary filters for Jupiter, Saturn and Mars. I also use Baader Moon and Sky Glow as light pollution filter to pull galaxies, globular clusters and comets from light domes. The effect is subtle, but often makes difference between seeing faint smudge and not seeing anything at all.

Yes,
it is difficult to explain why the Baader Moon and Sky Glow filter sometimes works on some galaxies.
Having a pair of these filters, unexpectedly, I have been able to see some condensations in the M66 galaxy in Leo through the 25x100 binoculars.

There is also an ongoing discussion about observing the galaxies from the backyard through the filters in
https://www.cloudynights.com/topic/7650 ... ry11043864

There are more things in Heaven, than are dreamed of in the popular filter lists,

JG

PS: Sorry for borrowing from Shakespeare

Good to hear that your experience matches mine, JG. I had DGM GCE "galaxy" filter in the past but found that Baader Moon and Sky Glow filter produces better results.

[Bigzmey]

Dug my filters out, besides the Mars, Moon and coloured ones, I have 2 Lumicons, the Olll and a Deep Sky.





I'll have to play around when the smoke clears.

Nice set of filters there. This is why Lumicon is my #1 choice. They not only have some of the highest transmission for OIII and Hbeta bands, but they also accurately list the actual measurements for each individual filter. I have tested quite few on the spectrophotometer in my lab and their numbers are dead on.

[notFritzArgelander]

............
I mean -- nothing personal here and now -- but some TransGalactic ranked user with 5000 posts and 9000 hearts is just someone without a life.
............

Whoever you are referring to more likely has a life that is quite pleasant and gratifying to them which is simply not understood by you. The pairing of "nothing personal" with the personal attack "someone without a life" is a hilarious example of self contradiction. Logic jokes are a genre of humor that is quite fertile

[WilliamPaolini]

Thanks to all. My interest was (is) in the O-iii and H-beta.

Hi Mike. I have a good spread of filters, but in the end I do not use them routinely. For the most part I find the improvements they provide are not significant enough (for me) to make them a normal part of my routine observing. Instead, I use them when I know my observing is going to be focussed on something in particular and I am not out for general observing. So I think the first consideration in an answer to your question is just how motivated you will be with filters and if you will not mind popping filters in and out all the time as you observe. For some they do not mind the added complexity, but others do mind. So first you need to ask yourself which category do you fall into.

As far as O-III and H-Beta, I have both. The H-Beta I have tried many times and do not find it very useful in my 4" to 8" scopes at either dark or light polluted sites. The O-III to me can be interesting on many targets to get a different view of the subject. Now not a "better" view, but a "different" (and some times rewarding) view. So it is useful to have around. With that filter, I also like to have a broader bandwidth UHC handy as well, one that lets stars through nicely without showing too much split-red in the star points(i.e., I like the broader UHCs that do not pass the red bands). I find that the UHCs that do not pass the red bands been the star field view more natural so like them more. I also like the broader band filters because they make the view look like I am at a location that is slightly darker and transparent then were I actually am. So it is like taking a trip to a slightly better site in an instant and I can still enjoy the rich context of the surrounding stars in the FOV. The more aggressive UHCs and the O-III can really wink out any surrounding stars in the FOV as they just cater to the nebula. This is nice to have for sure as it can reveal more structure in the nebula (which means not necessarily greater extent to the nebula FYI).

So bottom line for me is a good O-III and a broader UHC that does not transmit the reds are my preference. So with those I get a nice naked eye view with all the stars present, an improved nebula view with most of the contextual stars still present, and then the aggressive view for revealing the internal structures of the nebula better. So those two filters for nebula, then a Baader Contrast Booster plus a #8 Light Yellow and #82A Pale Blue for planetary handle all situations nicely for my needs as an observer in that category above where my preference is always to make my observing less complex so will only add the complexity of filters for when my observing focus really requires them.

[Bigzmey]

............
I mean -- nothing personal here and now -- but some TransGalactic ranked user with 5000 posts and 9000 hearts is just someone without a life.
............

Whoever you are referring to more likely has a life that is quite pleasant and gratifying to them which is simply not understood by you. The pairing of "nothing personal" with the personal attack "someone without a life" is a hilarious example of self contradiction. Logic jokes are a genre of humor that is quite fertile

I am not sure how been passionate about astronomy and overdoing it is "no life". What is the life then, Facebook and watching TV?

[Bigzmey]

Thanks to all. My interest was (is) in the O-iii and H-beta.

Hi Mike. I have a good spread of filters, but in the end I do not use them routinely. For the most part I find the improvements they provide are not significant enough (for me) to make them a normal part of my routine observing. Instead, I use them when I know my observing is going to be focussed on something in particular and I am not out for general observing. So I think the first consideration in an answer to your question is just how motivated you will be with filters and if you will not mind popping filters in and out all the time as you observe. For some they do not mind the added complexity, but others do mind. So first you need to ask yourself which category do you fall into.

As far as O-III and H-Beta, I have both. The H-Beta I have tried many times and do not find it very useful in my 4" to 8" scopes at either dark or light polluted sites. The O-III to me can be interesting on many targets to get a different view of the subject. Now not a "better" view, but a "different" (and some times rewarding) view. So it is useful to have around. With that filter, I also like to have a broader bandwidth UHC handy as well, one that lets stars through nicely without showing too much split-red in the star points(i.e., I like the broader UHCs that do not pass the red bands). I find that the UHCs that do not pass the red bands been the star field view more natural so like them more. I also like the broader band filters because they make the view look like I am at a location that is slightly darker and transparent then were I actually am. So it is like taking a trip to a slightly better site in an instant and I can still enjoy the rich context of the surrounding stars in the FOV. The more aggressive UHCs and the O-III can really wink out any surrounding stars in the FOV as they just cater to the nebula. This is nice to have for sure as it can reveal more structure in the nebula (which means not necessarily greater extent to the nebula FYI).

So bottom line for me is a good O-III and a broader UHC that does not transmit the reds are my preference. So with those I get a nice naked eye view with all the stars present, an improved nebula view with most of the contextual stars still present, and then the aggressive view for revealing the internal structures of the nebula better. So those two filters for nebula, then a Baader Contrast Booster plus a #8 Light Yellow and #82A Pale Blue for planetary handle all situations nicely for my needs as an observer in that category above where my preference is always to make my observing less complex so will only add the complexity of filters for when my observing focus really requires them.

I hear you Bill. Messing with filters in the dark could be annoying in particular when you have a manual mount and the target is rotating away. My answer to that is a filter wheel. Once you make it part of your setup changing filters is fast and pleasant. It also make blinking much easier to.

[notFritzArgelander]

............
I mean -- nothing personal here and now -- but some TransGalactic ranked user with 5000 posts and 9000 hearts is just someone without a life.
............

Whoever you are referring to more likely has a life that is quite pleasant and gratifying to them which is simply not understood by you. The pairing of "nothing personal" with the personal attack "someone without a life" is a hilarious example of self contradiction. Logic jokes are a genre of humor that is quite fertile

I am not sure how been passionate about astronomy and overdoing it is "no life". What is the life then, Facebook and watching TV?

All that one can see on this board is the passion and effort devoted to astronomy. Maybe there is a glimmer of other passions in off topic areas. Speaking only for myself I also spend considerable time making music, reading classic literature (just finishing a retraversal of Dostoevsky), spending time with family and a very few select friends, and continuing explorations of comparative religion, archeology, and mathematical physics. I certainly have a much richer inner life since I've retired. Occasionally I think of going back to work, but I am having too much fun.

Oh! Sometimes I'll spend an afternoon and evening playing chess with friends at my favorite cafe'. Once a week only though. My daughter has offered her kids a $100 bounty on the first one to beat me. I have vowed to defend her pocketbook to the best of my ability.

[mikemarotta]

Whoever you are referring to more likely has a life that is quite pleasant and gratifying to them which is simply not understood by you. The pairing of "nothing personal" with the personal attack "someone without a life" is a hilarious example of self contradiction. Logic jokes are a genre of humor that is quite fertile
I am not sure how been passionate about astronomy and overdoing it is "no life". What is the life then, Facebook and watching TV?

All that one can see on this board is the passion and effort devoted to astronomy. Maybe there is a glimmer of other passions in off topic areas. Speaking only for myself I also spend considerable time making music, lactic ranked user with 5000 posts and 9000 hearts is just someone without a life.

Well, I was not thinking of this board at all, or of a couple others that are even smaller. It was the one big board.

What I like about The Sky Searchers is specifically that it is a smaller community with a dedicated core of writers. The sociology of large groups is different than that for small societies. (A group of bystanders will not act in a situation where any single one of them would have.) I just did not keep that in the front of my mind at the time. It was my own failing that I took a set of comments prima facie without searching further. As I said, what happens often is that the first opinion sets the stage. You don't get a lot of discussion back and forth. Though, on that note, in this thread, I see that we do have some differences of opinion based on individual experiences.

What I meant by "nothing personal" was just specifically "not referring to anyone here" i.e., present company excluded. I would have made the same exception just for example on the SPA board. It's all very subdued there. As it is here.