Filters

[Wheels]

I understand the purpose of a moon filter, but I have other coloured filters, but don't know when I should use them & which colour is required for an object. Can someone explain this please.

[swamp thing]

Coloured filters usually have a Kodak Wratten number on.

http://alpo-astronomy.org/mars/articles/FILTERS1.HTM

This may help.

[Wheels]

Thanks for this, very interesting, explains a lot.

[LukeSkywatcher]

A Moon filter is of some use, but really not needed. The colour filters for use on planets are useless and i'd dismiss them totally.

[chiltonstar]

I use a deep blue filter for Venus to show the cloud markings, plus occasionally light blue or yellow for emphasising detail on Jupiter, Saturn and Mars.

For double stars, blue and red are useful; red will reduce scatter (blue scatters more and is absorbed) eg for looking at difficult doubles like Sirius A and B, and blue can be useful for very close equally bright doubles, as it reduces the size of the Airy disk and improves visual separation , eg Lambda Cygni.

So, don't throw your filters away, they can be useful!

Chris

[swamp thing]

A Moon filter is of some use, but really not needed. The colour filters for use on planets are useless and i'd dismiss them totally.

In my experience I'd say the exact opposite. Colour filters can help one pick out certain features when used on planets. Moon filters.........utter litter.

[Mike73]

A Moon filter is of some use, but really not needed. The colour filters for use on planets are useless and i'd dismiss them totally.

The best planetary observers that I know of all use coloured filters, the only problem with them is that you see the planet in blue/green/red. IMO if you want to see real detail on a planets surface then coloured filters are still the way to go, if you want a more realistic view of the planets disk then spend £100 on a fancy planetary filter.

Moon filters just aren't needed.

[AndyWB]

I found that a light blue filter does make a difference to the contrast on Jupiter. Curiously, it does also make me think that what I'm seeing is a bit greyscale.

I don't use a moon filter either. I find increasing the magnification dims things nicely.

[Moonshane]

For newtonian scopes (but not my refractor) i like the baader neodymium filter (or a light pollution filter is a close second) on the moon mars and jupiter. It shifts light to the blue end of the spectrum to my eyes but the effect at the eyepiece is vey natural.

I use colour filters on some double stars the sun and occasionally planets.

For the price of a used set they are worth a try. Red filters can create a more stable image of the moon.

[spaceboy]

I have found colour filters handy. #21 is good on mars, #11 on the moon, #82 or neodymium on Jupiter and moon, ND25 / moon filter for moon improves contrast but I have found this only works depending on magnifications and how full the moon is. #11 & #12 stacked gave good results on the sun for me when using Baader solar film.

[Wheels]

Thanks to all for the replies, this is all great stuff, I think I will need to try various colours & found what works for me.

[NGC404]

Think you will find on this subject, people on either side of the table will always agree to disagree.

Best go to your nearest astronomy club and try a few for yourself

From my point of view, a couple of favs

#21 yellow makes Jupiters cloud belts and transits/shadow transits stand out much more by making the markings/shadow transit darker 

against the bright disc

#56 green. On one occasion it gave me great views of the South Polar ice cap on Mars. Without the filter I could not see it