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1 hour ago, Bongo said:

Wow! That seems counter-intuitive initially. but I'll give it a go as soon as these pesky clouds clear.

Why not?  The worst outcome is loss of dark adaptation for a time.  You may need to adjust the brightness down a bit to find the level that works best for your eyes.

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The thought of those lucky enough to be able to observe with a 20 inch scope under really dark skies makes me go a tinge of green as well 

Try shining a bright flashlight (torch) onto a piece of white paper and stare at it to force your rods into the active state then quickly look in the eyepiece at the Orion nebula.  I've managed to cat

I'm sure someone will come up with the proper technical description, but basically, the parts of your retina that are very sensitive to low light, do not detect colour. In order to be able to see colo

Many years ago I always saw M42 with a greenish hue. It was quite unmistakable to be honest. I remember looking at it with my 8 inch SCT for the first time and that was the big wow moment. These days I don't see a hint of colour. That flashlight trick sounds interesting, I'll have a go at that!!! 

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15 hours ago, Pixies said:

Checked out the Eskimo nebula this evening and I do see it as green, but I wonder if that's my expectations playing tricks with me.

 

It is green for me and I don't expect anything, so I think you saw green.  I didn't even know what it was supposed to look like until I saw it first then looked at the internet.  Shows blue with an oiii filter.

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When I used my UHC filter on Messier 42 with the 12 inch dob a week or so ago I thought that the green tint was enhanced around the "fishes mouth" area and possibly even very subtle pink added here and there to the "wings" but I'm a little wary of what I think I'm seeing, colour-wise, with a filter in place :icon_scratch:

 

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9 minutes ago, John said:

When I used my UHC filter on Messier 42 with the 12 inch dob a week or so ago I thought that the green tint was enhanced around the "fishes mouth" area and possibly even very subtle pink added here and there to the "wings" but I'm a little wary of what I think I'm seeing, colour-wise, with a filter in place :icon_scratch:

 

I was also at one point thinking of mentioning UHC filter - but I wonder what the real effect behind that is.

It might have to do something with color adaptation rather than seeing actual color. This can be checked easily though.

Our eye/brain system adapts to different illumination to preserve expected color appearance. In broad daylight we see paper as white, but also - at sunset or inside our houses with artificial illumination - we also see that paper as white. Actual color of the paper is color of light illuminating it - but we pick up on general "scene" tone and our brain automatically adjusts perception.

When we look at the eyepiece - most stars that we see are fairly white-ish - no particular color to them unless we are observing particular stars. Sky is also fairly dark / gray maybe sometimes bluish. Our brain adapts to certain "neutral illumination mode" - and we see grey nebulosity because there is no enough light to trigger our color response.

Throw in UHC filter - and everything turns greenish / teal / blue sort of - all the stars turn into that sort of color and sky goes dark but it also now has that "tint". I think that we still see grey nebula but our brain now compensates for "general scene illumination" and turns grey into something else - although we are not actually seeing color?

This can easily be tested (maybe) - try using UHC filter on galaxy, will it turn greenish too - and should it with even less light reaching the eye?

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3 minutes ago, Captain Magenta said:

Whenever I search out Uranus I can definitely recognize it for its bluish hue, but then at mag 5.something compressed into a small area perhaps that would be expected? Neptune too

Yes, I agree that colour tints are easier to see in a more condensed target.

Uranus looked distinctly green / grey disk when I observed it just now. That was with a 100mm refractor at 300x.

 

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2 hours ago, skyhog said:

Many years ago I always saw M42 with a greenish hue. It was quite unmistakable to be honest. I remember looking at it with my 8 inch SCT for the first time and that was the big wow moment. These days I don't see a hint of colour. That flashlight trick sounds interesting, I'll have a go at that!!! 

I have similar memories from just a couple of years ago, observing M42 with street lights close by. Noted that the nebula had a distinctly greenish hue. Can’t say I have seen it since, then again I haven’t observed it under the same circumstances. I shall have to remember to take note next time.

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I’m sure I read somewhere once that the greenish colour we sometimes see in nebulae  is from hydrogen beta as our eyes are more sensitive to this part of the spectrum. Not sure if that’s right. 

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I just came in, and the last thing at which I looked was the Blue Snowball. I am sure that my 60-year-old eyes can see some tint in the image produced by my 8 inch SCT.

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15 hours ago, skyhog said:

Many years ago I always saw M42 with a greenish hue. It was quite unmistakable to be honest. I remember looking at it with my 8 inch SCT for the first time and that was the big wow moment. These days I don't see a hint of colour. That flashlight trick sounds interesting, I'll have a go at that!!! 

I was looking at Orion the other night through my 8SE, and it was quite clearly a greenish hue. I was reading this thread and wondering if I had imagined it, but glad to hear I wasn’t!

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Along with M42, M27 is another object that sometimes appears vaguely green to me in only 120mm.

Anyone with the ability to see red in DSO's needs to donate their eyes to medical science.😉

As an aside, double stars colours generally appear richer in an achromat (green star anyone?)~it's not  a 100% accurate rendition, but no less pleasing for all that.

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4 hours ago, SiriusB said:

Anyone with the ability to see red in DSO's needs to donate their eyes to medical science.

Sounds like a plan lol!

I see green and salmon pink in M42 with my 15" and green, pink and also blue with my 24". Skies can be pretty good here darkness wise. A note about dark adaptation- M42 ruins it for me, too bright.

Mind you maybe the brain fills in information (color) after repeated observation- is it an illusion?:grin:

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Hi. I observe from Australia, and the Orion nebula M42 appears very green to me! I use a 10" dob. Also the Tarantula nebula NGC 2070 in the SMC has a light green colour too it as well as faint pink regions. Cheers

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I see M42 as a sort of pale lilac-green. One problem I suppose in judging the colour of nebulous objects is that the Purkinje effect may make things look slightly blue, and also after using a red head torch, colours may be distorted until the eye adapts again.

Chris

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2 hours ago, CraigT82 said:

M42 looks greenish to me too, even in my H130p. I think I remember @ollypenrice stating that their 20" dob under dark skies shows hints of red/purple

Not to my not-very-good eyes but some observers reported that. 

Olly

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