Filters for viewing mainly

[gcraib]

I've been reading through the site and online about filters as I'm considering buying some for use with my skymax 127.

The primer on filters was brilliant but I'm still left with some scope specific questions.

At the moment I have the moon filter that came with the scope (that is ND right?) and purchased a 2" LP filter that sort of works ok.

Oh and a solar mask aswell.

I'd like to buy some colour filters to improve views on planets and possibly on the sun too? What is a good all round kit (eg a red, blue, yellow/orange and green) that would work well with this scope?

Also is it worth buying another ND filter (perhaps not so dark as the moon filter) for improving contrast and views on nebula/red spot?

I saw contrast booster filters online and the description was good but not sure if they are worth it?

I'm thinking 2" filters so I can use with EP's and with DLSR in the diagonal although this is more expensive, so its important to make an informed choice.

I haven't really done much imaging, nothing decent anyway so filters for that is a long way off, but I have seen RGB(LC) for use and wondered about that if I already have coloured filters for visual.

Also a UHC might be a good idea as the OIII would be too dark for my scope? (or is the contrast booster etc better for 5" scope?)

Is the IR cut and IR booster any use for visual or imaging only?

What sort of differences can you expect in the EP through a 5" scope with these filters?

I live in a small city with moderate light pollution but sometimes travel to darker sites with little or no LP.

[gcraib]

**bump**

[swamp thing]

Hi

I personally don't do a great deal of planetary observing and zip solar and imaging, so I'll not comment on that side of it.

For deep sky, either a UHC or O-III will help greatly with emission nebulae.

Some find the O-III to aggressive with small scopes. I don't, but either way a UHC or O-III is deffinitily worth a look.

Even from a dark sky they can both really help.

Some times they can actually make the difference between seeing an object or not.

Neither will help with open or globular clusters, reflection nebulae and Galaxies. The only thing that improves these is better skies.

Hope this is of some help.

Regards Steve

[catburglar]

My skies are about 4.5-5 limiting magnitude, on the edge of a town with a population of around 150k. Neighbouring security lights are the biggest source of light pollution. I can faintly see the summer milky way with the naked eye, and just about see the Beehive unaided in Spring.

I've used a couple of UHC filters (Baader and Skywatcher) and OIII (Skywatcher and Castelli) in an 80mm refractor. Of the two types I'd definitely say the OIII makes the biggest difference, and it's quite dramatic for some objects. OIII would be my first purchase. Of course, the UHC filters may benefit you more depending on your local light pollution.

I haven't got quite such a clear position on planetary filters. I found a light red and blue filter helpful for Mars, but for Jupiter and Saturn I've tried a range and found no great benefit. I think for planets, seeing conditions and observing the planet when it's highest in the sky make a much more profound difference.

[Mark at Beaufort]

You may find this website helpful - The Prairie Astronomer

Over the years I found the UHC the most helpful so personally that is the one that I would buy first.

As previously stated I have never found colour filters that great but I know some astronomers do. Again this website might be helpful. Visual Astronomy: 4 Color Filters You Should Have

I imagine your Moon filter is a ND as you say - helpful on Jupiter.

You might find this filter helpful and it does help with the GRS on Jupiter - First Light Optics - Baader Neodymium Filter

The IR filters are really for astro photography.

Finally the Sun - I assume you will buy a good solar filter and you may find that members on this forum state that a green filter helps.

Hope this helps.

Mark

[rwilkey]

The variable polarizing filter is a good one, as you can vary the transmission of light recieved, just right on the Moon and the planets: First Light Optics - Variable Polarizing Moon Filter It also darkens the background and helps with contrast.

[arbacia]

Gcraib,

You don't need contrast booster filters

For nebula I recomend you a NPB filter. This is an UHC-like filter, very similar to the Lumicon or Astronomik but better in contrast (!) and in color (the hue is not green as in the UHC, but grey). Moreover is cheaper. From Europe the best way to get it is from the ebay shop of the USA distributor (Omega Optical), just type "DGM NPB" in ebay.

To use an OIII filter in your telescope, you need to be dark adapted, use very low magnification and cover your head to get an image no so different of the one obtained with an NPB.

Note than Baader UHC is not an UHC but is a UHC-s, similar to the Astronomic UHC-e, and the same than the Celestron UHC-LPR. All of them were intended for small aperture telescpes (as the ED80). They are not narrowband filters such as the Astronomik UHC, Lumicon UHC or DGM NPB which are real narrow band filters.

For the moon I use the variable polarized filter only in public observation. I never use it. If needed I use a red filter since: 1.- reduces transmission, 2.- reduces the effect of bad seeing and 3.- increase the contrast in mare materiasl (the titanium rich basalts become darker). Alternativelly use a photographic 48mm ND filter (grey, I use ND 4 and ND8, but I use 11" and 16" tubes)

If you want some color filters, the orange #21 will be really great in Mars. Add a medium blue (#80A) and perhaps a red (#23 should be nice in a 127mm). I almost never (or never) use yellow or green (although the yellow-green #11 is great for the GRS of jupiter)

Patricio

[arbacia]

Respect the IR filters, they are for photography. Both of them, 1.- the ones that cut the IR leaving only the visible light to pass through and 2.- those f low pass that cut the wavelenght shorthed that a particular wave lenght.

The thing is that long wave length light is less distorted by turbulences than the shorther ones. As stronger the turbulences are the longer wavelenght filter I select. (the counterpart is that longer wave lengh has less resolution than the shorther, so we need to consider that and balance the decission)

On the other hand, longer wave lenght light make focus in a different plane that the shorter ones. For that is the use of UV/IR filters as they cut the UV and IR light that our eyes ca not see but the camera regiter.

To use the IR pass filters you need a sensitive camera IR and most of the non specialized cameras have already an IR cut filter inside.

If you go towards photography with a monochrome and no filtered camera (such as DMK or Luna), for your telescope first try with a planetary red filter (the one for visual as they are also low pass filters cutting about 610nm). Later if you need a more restricted one The Baader IR 680 should be fine.

Patricio

[gcraib]

Hey guys just reading this again, forgot to say thanks for the responses.

I'll probably buy the neodynium and possibly UHC (both baader) in 1.25" and consider the variable polarising.

[rwilkey]

Gcraib, you already have a 2" LP filter in stock, will you really need the neodynium filter as well? You can use the 2" with 1.25" ep's by mounting the filter in the 2"-1 1/4" adaptor....

[gcraib]

Do I not need the neodymium if I have the LP?

I thought the neo was more than LP?

[rwilkey]

The Neodynium filter was essentially a light pollution filter, but more recently it has had reviews where it is said to be good as a Moon filter, and also enhances other features on planets like Jupiter and Mars.

[West End Wendy]

Yes, just seconding what Robin says above - I bought my neodymium as a light pollution filter but now use it exclusively for lunar and planets.

Tim