Colour Perception

[barees63]

Hi all,

I've been wondering about colour perception when viewing, I seem to see very little if any colour when viewing object like M42 and Ghost of Jupiter.. When I showed M42 to my brother and my daughter both remarked straight away on the blue-green colour but when I look at it I see shades of gray, similarly when viewing the Ghost of Jupiter last night, I knew it was bluish from looking at photographs but to me there was no really distinct colour yet on looking at some web-pages about it tonight most remarked that it is seen as distinctly blue through a telescope.. do you find people have varying degrees of colour perception at night or is just me? :confuse3:

Bruce

[Robert_T]

Hi Bruce, colour perception of very faint objects is a bit of a combination of physiology (how good your eyes are and the function of the light and colour receptors in your retina - "rods" and "cones" though I can never remember which is which) and practice. Many observers report that the more and longer they observe objects such as M42 the more colour they see, even the pinks as well as the green - not that you'd ever see the same vividness of colour that images bring out.

cheers,

[RAJAH235]

Bruce, The human eye processes the info received immediately, unlike a film or ccd. Therefore to actually 'see colour' we need a fairly large aperture t'scope to gather the avail photons. The cones are the cells that do this. ( cones = colour).
With a larger t'scope, >8", you should be able to see a faint green glow in M42, poss a bit of pink to very faint red. Age becomes a factor as well.
I can see green with just a hint of pink in my 10" dob & @ 60 yrs, I think that's great. Conditions have to be pretty good too. :D L.

[[1ponders]]

Yep, age, genetics, observing skills and sex (yep woman can see colour better than men, lucky ladies) can all play a big part in this. To me the blue planetary is definately very blue and M42 is definately greenish (most of the time and depending on what scope I'm looking through). Yet a friend of mine can only see the blue planetary as greenish and sees faint pink in M42. The bottom line is some eyes cant, some eyes can and much of that depends on conditions.

[jjjnettie]

Sounds like you need to eat more carrots Bruce. Australian S&T has an article on how to improve your night vision. It might be worth having a look at.

[RAJAH235]

For the lowdown on "all things eyes", why not simply ask your local Optometrist or Optician. Bound to have a store near you. Only too happy to help....Luckily we have one in our club.. :D L.
ps.carrots ain't gonna cut it..

[barees63]

yes, it's weird.. I have seen an optometrist and eye specialist recently (not related to astronomy.. just reading/work I'm a programmer by trade) but apparently there's no problem other than normal aging, I seem to see plenty of detail and I see colors on stars (eg jewel box) and planets just not the nebula colors.. oh well.

[fringe_dweller]

I have always been surprised how little colour people report seeing in m42 on this forum, to me it has always been very, very colourful. In addition to the straight winegum green and blue's i see a lot of magenta/violet.

[ving]

you, oh dewller of the fringe are a very lucky person :)

I see a very vivid green in my 8" and a somwhat duller green in my 60mm :)

[fringe_dweller]

hehe thanks David :) think ill have to donate my eyes to science by the sounds of it? LOL!
Pity about the exponentionally multiplying with age floaties ;( they are getting to be a nuisance!

[ving]

can the floaties be removed?

[fringe_dweller]

Not that I know of mate - I dont even know what causes them :confuse3: but everyone gets them eventually, I believe?
EDIT: they are much worse when my eye's or myself are tired ie. too much online gaming or reading (especially off the puter)

[stinky]

I believe floaties are chains of proteins. Here is an interesting illusion that shows how the cones in the eye work - particularily persistence. Try it out. For some the effect is instant - others need to stare.

http://www.patmedia.net/marklevinson/cool/cool_illusion.html

[Starkler]

I saw on tv once a laser procedure for zapping large floaters where they become a problem for normal day vision. Whether this can be done to the satisfaction of observers I dont know.

[ausastronomer]

Bruce,

You raise this question at a very opportune time.

Firstly let me say as others have, that everyones eyes are different and perceive low levels of colour differently. In addition perception of colour in diffuse targets is apperture dependant as a larger scope plain and simply allows more photons to strike the cones at a given instant than a small scope.

I spent a bit of time with Andrew Murrell and his 20" scope discussing colour in M42 on Friday Night and with Houghy and Ed Roca (Orion) discussing exactly the same thing around Ed's 18" scope on Saturday night, at IISAC at Lostock.

On the Friday We observed M42 in the 20" at twilight and it was very greenish in colour. Andrew Murrell explained that this effect was very pronounced at twilight and the colour faded significantly as the skies darkened, this is exactly what I saw. Why, I have no idea.

On the Saturday I observed M42 in Ed's 18" scope with Ed and Houghy through a couple of different eyepieces belonging to Houghy. Including a 20mm T5 Nagler, a 24mm Meade S5000 Super Wide and a 34mm Meade S5000 Super Wide (I think it was). I must say both the Meade eyepieces were physically very impressive if bigger is better, they were marginally larger than a house brick and about as heavy :) . Reasonable performers in Ed's F4.5 scope, not as good as the 20mm Nag T5 which is infinitely more expensive. I was able to detect some pink and blue tinges over various parts of the nebula in all the eyepieces, no green. So here we have it green on Friday and pink and blue on Saturday. Two similar aperture telescopes on consecutive nights under similar conditions and spaced 30 metres apart. GO FIGURE, cause I can't figure it . But it gets better, later that evening I returned to my own 10" dob and got perceptions of green in M42, 2 hours after I got pink and blue in Ed's scope.

CS-John B

[rumples riot]

Bruce, I have to agree, colour is largely dependant upon transparency, your eyes and the scope you are using. In both my SCT's I sometimes see greenish hues and sometimes not. Larger scopes generally show with my eyes more colour. Don't worry, though the view is all that matters, not the colour.

[barees63]

I wonder (having read the AS&T article) if this is due to the "cones" which perceive colour progressivley switching off as it gets darker in favour of the rods which are for night vision and do not perceive colour. the other thing I notice is I seem to have weaker perception of blue at night in particular so that may explain why I can see red/yellow stars and planets with ease but struggle on blues and greens.

I'm not really too worried as I never expected to see colour in nebulous objects anyway.. just a bit miffed when others go on about the wonderful shades of green/pink/magenta they are seeing (********!) :-)

Fringe-dweller, I have increasing floaters in my eye as well, particularly the eye I use for the telescope (dammit!), the optometrist told me most floaters are remnants of blood vessels?

[slice of heaven]

Your not alone

I only get black and white reception also :sad:

[barees63]

maybe those other bozos are imagining it? looked at too many Hubble pictures so brain colours it in for them? :P

[OneOfOne]

Damn it, I thought I could see black holes!:lol:

[venus]

Maybe it's just that astronomer are more observant of changes in their eyes due to the fact that they give them extensive use when viewing?
I know I have noticed my vision changing in the last few years and friends who arn't astronomers haven't complained like I have either.
I was really suprised to see the brilliant light blue in the ghost through Andrew's scope at IISAC last Saturday night, Andrew was a wealth of info on astronomy on the night sky and a very nice person as was everyone I met at the camp.

[fringe_dweller]

Com'n guys! you all having me on arent you??
There are lots of colourful images of neb's and other objects from hubble yet M42 is the only one I see colour in like that (other than blue/green PN's) - and its quite different colour scheme to a hubble shot - mostly I see M42 as a degree or sometimes more long giant eerie luminous purple vampire with wings/arms partly extended - a bit like the barcardi bat - with the wings fading into the night at near it feet ;) take that the visually challenged! you cant buy what i got :P
I love that new acronym B(lessed). O)(ptical). Z(one). O(perators). of S(copes). :P
by the way (nice show of balanced unbiased moderating again there ;) or is it as kangaroo court system?)
And as for the twilight theory - why doesnt that work for the other big nebs and other objects, ie why wouldnt that turn the LMC green/blue?!!?
Guys's, the floaters are the biggest nuisance (there is usually only one really bad one in my right eye) on planets I find, looking like odd moon shadow transits hehe - but i have learnt to train my eye into tricking it/them into moving out of way - a bit like a flea circus ringmaster!
I have always felt a pang of pity when I hear the story that people are going to get into AA when they retire - i am very very glad and grateful I started when i was 30 - at least I will know what i am missing when i am run into those problems in the future :( although one of my best observing buddies is colour blind and that doesnt seem to impinge on his enjoyment too much at all.
I guess thats why imaging is so popular?

[barees63]

of course I was only kidding! I'm just jealous..

[ausastronomer]

Absolutely nfi, but I know what myself and a dozen either people at Lostock IISAC saw. Andrew Murrell predicted it, so I suggest you send him a PM and ask him. If you can wait a bit I will be talking on the phone with him within the next few days and I can ask him as I am also curious.

CS-John B

[fringe_dweller]

Bruce, I knew it was just a good natured ribbing between observers ;) but in writing, can be percieved many ways as others have mentioned before.
Perception is a subjective thing as you all know, for instance try and tell people the sky really isnt blue - its in the eye of the beholder - it actually should be more violet /indigo but we arent supposedly as receptive to this part of the spectrum.
I totally agree Venus - we are pushing beyond the limits of normal use of eye's and are more sensitive to changes - well worth mentioning.
Another one of my favourite astro trivia facts (have a lot stored) is the oft mentioned one that if the Tarantula was in the same spot as the Great Nebula of Orion it would fill as much as 80% of the night sky - and at night cast a purple shadow across the earth :) how cool is that!
There was a very, very interesting thread from Laurie on this subject -
http://www.iceinspace.com.au/forum/showthread.php?t=5972&highlight=rajah+cones

[astro_south]

Was out at my society's dark sky site over the weekend and easily saw colour in Orion in a range of scopes. I was lucky to have intermitent use of a 30" and a 22" F5.7 (almost all of Saturday night was devoted to the 22"). I spent a fair bit of time showing the owner of the 22" scope the Horsehead and how to identify it. Naturally in the area I visted the Flame Nebula a few times which was amazing in this scope. Now after a while staring at it I am sure I noticed a dirty orange colour to the nebula. I haven't found any other evidence of this in my limited searches, and the guy I was with said he saw it aswell, but he might just have been convinced of it via my observation. I am not sure if my eyes were playing tricks and my imagination was getting in the way. I would have thought the nebula is so dim that it would never show colour, but then again I have read of people seeing colour in the North American Nebula - so I guess it is possible. The seeing would barely rate a 5-6 that night, but the transparency was great.

In Orion in my 12.5" dob I see the bright core and the 'wings' as mostly a grey-green, but I see the nebula inside the brighter wing arches as a distictive ruddy pink. The key to noticing the colour is to concentrate on the dark area that leads into the trapezium. The pink in the nebula really contrasts well against the dark lane and this may help in seeing the subtle colour. I have also seen colour in the Trifid nebula in a 16" scope on a good night.

[barees63]

The weird thing for me is I looked back thru my log book and the second time I took the scope out I had written "M42 some blue/green color?".. My (probably specious) theory is, since the two people I showed M42 who had never looked thru a scope before instantly saw color and I apparently saw it the second time out but never since, is that as my eyes have become better at dark adapting I am losing the use of some color receptors in favor of night-vision rods..

[fringe_dweller]

Bruce maybe you should flash youself in the eyes with a torch just before taking a look at M42 :D Its a thought!
I was thinking about other easy colourful sights outside of M42, PN's and planets (and stars of course - and golden GC members)
I forgot about comets :-) :doh: they can have blue/green heads and can have blue or green ion tails of course! and in dusty ones the golds and yellows of reflected sunlight, naturally.
My favourite colour yet in a smallish comet, was in early may 2004 on C/2001 Q4 NEAT from a very dark site, I very easily saw with my 8x56 bino's the broad curved ~1º long, exotic dark and dirty weird green of the CO2 type III tail - pretty damn rare i believe :-)) My rarest colour in the collection :-)))
Andrew - I believe too with enough aperture like you guys have, and trained experienced eye's in very dark skies, hints and suggestions of colours must abound in the universe!

[RAJAH235]

fwiw, your eyes become 'dark adapted' 1/2 hr to a 1hr after zero exposure to white light. Fine. This varies with age. ie; increases...
But, when you view an object that is faint ie; neb or the like where colour is known to be seen by others, just take your time at the E/Pc & let your eyes become 'dark adapted' to the new 'darker'? scene. You'd be surprised how the details & colours can be discerned after a few mins viewing.
Not really a matter of 'training your eyes' imho. If your eyes cannot 'see' colour, (sorry Slice & others), because of lack of cones or genetics etc, then you never will 'see it' in the fainter objects.. Just not enough 'light' to activate them..etc etc...
:D L.

ps. Fringey, only if it's got a red or green LED in it....:P

[barees63]

There may be a bit of that, since I got the AN going I have tended to flit from one thing to another, maybe I need to slow down a bit ;-)

[RAJAH235]

Yep, take it a little slower. After all, the Universe ain't going anywhere in a hurry! or is it??? :D L.

[slice of heaven]

I gotta get a 30" :prey:

[RAJAH235]

Lets face facts here Geoff, you're just not suited to Astronomy! :P :P :P :poke: :D L.
ps. The 30" might help a tiny bit, but.......