Filter for Planets Advice

[Albenn]

The views I get of Saturn through my Heritage 130 are pretty clear and detailed but I wondered if there would there be any improvement if I used a filter?

If a filter is advised, what type/make would be best and would it also be suitable for Jupiter?

[E621Keith]

Here is a short guide to using filter for astro

http://www.licha.de/astro_article_buying_guide_filters.php

I usually use a Baader Neodymium filter to darken the sky.

When I observe with my larger C925 I use a Sirrus Optic variable bandpass filter.

[Albenn]

Thanks for link Keith. Quite informative.

[Qualia]

Albenn, you might find these useful:

http://www.lumicon.c...id=1&cn=Filters

http://www.agenaastr...ary-filter.html

http://www.oaog.ca/w...ary Filters.pdf

Other than that, all I can say is that this one will be a personal voyage. You see, some folk loath filters, some love them, so in the end you'll have to decide on your own.

All filters will reduce light in some manner or form, so be careful. In many cases, especially with your 5" for solely visual use, it is exactly that light you are after.

I've heard that the Baader Neodymium Filter or the Skywatcher Light Pollution filters are very useful in LP areas. ND moon filter for, yup, looking at the bright moon. I got a decent Baader moon filter with my Tal but I have never really used it, for I prefer the natural light, especially for sketching.

I have found Baader's UHC Nebula filter quite useful, don't expect magic but it does make some difference.

Of planet-colour filters I have no idea,, so I hope the above links help in some manner of form.

Good luck with whatever you decide to do and if you do purchase, please let us know your thoughts.

[Albenn]

Thanks Qualia. Much food for thought which should help me decide which filter to try.

I think that deciding on the filter will be quite straightforward and should be done and purchased by the end of next week. However, it may take a few weeks after getting the filter to report my findings on it as the weather here in the UK has been awful and shows no sign of improving any time soon.

Hope you're having better weather over in Spain.

[Stu]

Yes, fuuny things filters!

I've found the neodymium works very well on Mars, but wasn't useful at all on Saturn. Haven't used it much on Jupiter but would expect it to help bring out the features better

Stu

[Northern Soul man]

Hi Alan, theres also a variable polarising filter that might benefit, 2 filters screw together and when rotated 1 against the other, it alters the light transmission from 1 to 40%, a little fiddley to use at the scope - but if you have a bright image, the filter darkens it as to enhance detail, but , as said above filters are like Marmite you either love em or hate em, its down to personnel preference, best to see if you can borrow a few and experiment as coloured filters offer false colour images - so an orange on Mars gives you an orange Mars but the land forms stand out a little better - but as you know Mars visually is different shades of grey, dark gray and whitish polar caps and not the nice false colour and doctored images you see from photos from the imagers and of course the fantastic Hubble telescope. Cheers Paul.

[Albenn]

I've found the neodymium works very well on Mars, but wasn't useful at all on Saturn. Haven't used it much on Jupiter but would expect it to help bring out the features better

Thanks Stu. Just had a look at the Baader neodymium filter and wondered if my Meade variable polarising filter would do the same job?

[Albenn]

Paul. You must have been reading my mind! I was busy writing my reply to Stu and didn't see your post until I'd finished.

[umadog]

"Just had a look at the Baader neodymium filter and wondered if my Meade variable polarising filter would do the same job?"

No, they're not the same. The Baader passes light only at some wavelengths. Here is the all-important transmission curve: http://www.astrosurf.com/buil/filters/curves.htm#Baader%20Neodymium (you may need to scroll up or down to see it). So it's basically sky-glow filter. A variable polariser is really a variable neutral density filter. So that will attenuate all wavelengths.

The Baader should help bring out contrast in nebulae and possibly a little on galaxies. A variable polariser will just absorb light and shouldn't be used on such objects. Some people find planets too dazzling at the eyepiece. In this case a variable polariser can help. The Baader filter cuts out some light (that's how it works after all) and so it too will make the image dimmer. The fact that it lets through only certain wavelengths may well help to bring out planetary detail. Doubtless some people will what it does on planets and some won't.

Probably there's nothing particularly special about the use of the Baader for planetary viewing. You can whack a Lumicon UHC (or any LP or narrow-band filter) into the light path and view Jupiter and some features will appear enhanced. Again, some will like what they see and others won't.

[E621Keith]

Thanks Stu. Just had a look at the Baader neodymium filter and wondered if my Meade variable polarising filter would do the same job?

Alan, sorry if my post confused you. Just as umadog said, Baader Neodymium and variable polarising filter are very different and don't do the same job..

Baader Neodymium filter is a light pollution filter that is designed to reduce the effect of light pollution and cut down on sky glow. It darkens the sky background make the image less washed out. Other light pollution filters can do the same job, IDAS-LPS, Astronomik CLS etc...

Variable polarising filter allows you to adjust image brightness (transmission). It's only useful for lunar observation near full moon and shouldn't be use on anything else.

I think my comment about the Sirrus variable filter may have confused you. The Sirrus filter is an interference filter with a adjustable bandpass, it's very different to a variable polarising filter. The Sirrus filter is a bit like a continuously variable colour filter wheel.This filter is not made any more, but do occasionally appear on the used market.

If you're interested in how it works this, CN article explains what it does, otherwise please just ignore that line. http://www.cloudynights.com/item.php?item_id=917

[Albenn]

Thanks for all the info guys. I'm sure all the info I have received here will help me choose the correct filter.