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Filters

Langworthy

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LukeSkywatcher

LukeSkywatcher

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For observing planets and dragging out fine details most people would use a set of coloured filters (wratten).

Something like this: there are cheaper sets

http://www.firstlightoptics.com/visual-oberving-rgb-filter-sets/baader-6-colour-filter-set.html

For observing nebulae, you have a choice of either a UHC filter or an OIII filter.

http://www.firstlightoptics.com/uhc-oiii-visual-filters.html

A UHC filter will enhance nebulae that you can see with the naked eye (M42) etc. An OIII filter will make nebulae not visible to the naked eye, visible (The Rosette,The Veil)etc.

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LukeSkywatcher

LukeSkywatcher

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... As long as you have a dark sky

Well yes, the darker the sky you have the better filters work. Jem is in south Wales, so i dont think dark skies are too far away.

I used to live 20 Km south of Dublin city and i found coloured filters useless, but the UHC and OIII worked well from there. I did also use a light pollution filter in conjunction. My skies there really were not too bad, i have to say. They are probably worse right where i am now, but i can take a stroll 5 mins from my house and be in open farmland with almost no light pollution. All i did was move about 30Km inland.

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jambouk

jambouk

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I think some people, i was in this category, think filters will make the world of difference. What is important to remember, for visual work, is that filters cut out all light to an extent, but the aim is to cut out more of the unwanted stuff, and for simple coloured filters for planetary observing, i disn't find them that helpful with light polluted skies.

As always, if possible, borrow some and try them with your eye pieces, your telescope and your observing locations. See if you think they make a difference.

It would be interesting to know how many "serious" visual astronomers use them in accordance to where they live (and how much light pollution they are subjected to).

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Langworthy

Langworthy

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Well yes, the darker the sky you have the better filters work. Jem is in south Wales, so i dont think dark skies are too far away.

I used to live 20 Km south of Dublin city and i found coloured filters useless, but the UHC and OIII worked well from there. I did also use a light pollution filter in conjunction. My skies there really were not too bad, i have to say. They are probably worse right where i am now, but i can take a stroll 5 mins from my house and be in open farmland with almost no light pollution. All i did was move about 30Km inland.

Actually though I can view from my drive, I am in the middle of a village with one particularly bright street light 50 yds away to north-east. I doesn't interfere directly with southern sky viewing but it is a pain, particularly since it dazzles me from time to time when I catch sight of it.

Loading up and a short drive of a mile or so does the trick. 

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ottUp

ottUp

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would anyone advise that I get any filters? If so, which colour and for what purpose? Would they assist with planets and nebulae?

Cheers one and all.

Here's an article that discusses what the various filters are for.  Most are very subtle in effect and may disappoint if you are expecting magical results.  A narrowband filter for nebula viewing is a good investment, though, if you have dark skies.

- Richard

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LukeSkywatcher

LukeSkywatcher

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Here's an article that discusses what the various filters are for.  Most are very subtle in effect and may disappoint if you are expecting magical results.  A narrowband filter for nebula viewing is a good investment, though, if you have dark skies.

- Richard

I think that is a very fair article on filters. 

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LukeSkywatcher

LukeSkywatcher

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No need for one. Its only when the Moon is ful that it can be too bright to look at, but it wont damage your eye. Its about the only time and the worst time to use a filter because there simply is no contrast of detail on the surface. Yes it will dim the light during a full moon but you wont see any contrast in details on the craters etc.

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LukeSkywatcher

LukeSkywatcher

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I find the "moon" filter is the only one i ever use!

It cuts down the brightness and stops my retina burning.

James

Try observing without it. You wil quickly become accustomed to it and most likely never use it again. Even when there is a full moon.........but like i said, that is the worst time to observe the moon.

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jambouk

jambouk

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I agree at full the contrast is poor, but for non astronomers they are interested in looking at the moon and seeing the more prominat features of mare and mountain ridges which can be easily seen at full moon - and the filter just reduces that uncomfortable burn which does hurt and really can't be good for the rods and cones.

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LukeSkywatcher

LukeSkywatcher

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I agree at full the contrast is poor, but for non astronomers they are interested in looking at the moon and seeing the more prominat features of mare and mountain ridges which can be easily seen at full moon - and the filter just reduces that uncomfortable burn which does hurt and really can't be good for the rods and cones.

I agree that non-astronomers will see the differences in colour between the highland and lowlands even during a full moon. What they wont see is the shadows cast in the craters and by the mountains, which us astronomers see when the moon is not full.

They/we get better views when the moon is not full. Why not show them the moon when its at its best and they can see the terminator etc.

p.s.~~~the moon at full phase will not damage your eyes and the rods and cones. 

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