15x70
member
Reged: 10/11/03
Posts: 94
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I have just read a post in one forum and a guy said that “we can not see any colour even with a giant scope”. But I doubt if it is true or not. Some veteran observers say that it is possible to see nebula colour through huge scopes, even small scopes. One guy claimed that the M42 that he saw was greenish.
But I feel confused at this moment. As a student who studying Biology, I have a concept that we can’t see things with colour. 
Is there anyone kind enough to tell me the truth? 
Edited by 15x70 (11/15/04 04:22 AM)
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Jake Saloranta
super member
Reged: 10/04/04
Posts: 159
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I think we can see some colour from the brightest object, such as Messier 42, and planetaries due the high surface brightness probably. But this is where it gets tricky - one sees green, one blue and one nothing at the same moment, I have tested this with my non-astronomy friends  Others are more sensitive to blue light and so on. And with larger telescopes, objects become brighter and so on show colors more easily. Also seeing colour depends a lot on sky conditions. All planetaries look pretty much grey from my backyard but under dark skies, almost always show some kind of colour.
So is the Blue Snowball nothing more than #!"#!? Sometimes, yes, but under dark skies and @ low power, one might see it as blue.
If you wanna test this colour thing, try for example M4, M13, M42, NGC 6543, NGC 7662, NGC 2392 and so on and share what ya can see with the group.
Jake
PS. Always put star-gazing before your study! 
PPS. Fine mods, the word's changed now, hope yar all happy now 
Edited by Jake Saloranta (11/15/04 05:08 PM)
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Bird
Carpal Tunnel
Reged: 08/07/03
Posts: 2566
Loc: Canberra, Australia
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Under dark skies I can see the green colour from M42 with the naked eye, and even more so in binoculars. That's probably the best bet to see any colour in nebulae.
I can't see it from here in town - but if I am camping out in the national park where there are no lights for a few hundred km then this colour is visible.
Bird
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Deep Sky Optics 13.1" f/5.5 newtonian,
PGR Dragonfly Express, PGR Dragonfly 2
RedHat Linux + Coriander
http://www.acquerra.com.au/astro/
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cildarith
Carpal Tunnel
Reged: 08/26/04
Posts: 1978
Loc: San Diego, CA
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I've had the pleasure of viewing M42 through a 48-inch cassegrain. There simply are no words to describe what that looks like - but there is definately color! Green mostly - really bright green!
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Eric
6" f/6 Parks Newtonian
10x50 Bushnell Binocs
CN Sketch Gallery
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MMICKELS
Aluminum Knight
Reged: 01/20/04
Posts: 23340
Loc: The Land of Shake and Bake
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I've seen color in M42 even in my town. Green is the color I see.
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Mark
"The only thing wrong with immortality is that it tends to go on forever."
Herb Caen
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BillFerris
Carpal Tunnel
Reged: 07/17/04
Posts: 2435
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There are many reliable reports of observers seeing color in nebulae through small and moderate aperture telescopes. Personally, I've seen M42 as forest green, lime green and several other shades of green in my 10-inch Newt. I've also seen color in planetary nebulae (greens and blues) and in bright galaxies (blues and yellows).
Some folks may hold to the notion that we can't see color in nebulae because they assume the eye is fully dark adapted when observing through a telescope. When fully dark adapted, the eye's rod cells dominate visual perception. This is described as scotopic vision. Since the cone cells are responsible for color perception, it would be logical to conclude that we can't see color in nebulae if fully dark adapted.
The problem is, we're often not fully dark adapted when out with our telescopes. Much of the time our vision can be described as mesopic: relying on both rods and cones for visual perception. This is because even the darkest night sky is still bright enough to stimulate cone cell activity. With the cones still active, color perception remains possible. Hence, our ability to enjoy the colorful hues of Mars, Antares, Vega and aurorae.
Observing through a telescope lowers the sky brightness. But for large & bright nebulae like M42, observers often use low magnification. Sky brightness--even through the telescope--remains high enough that mesopic vision still prevails and, if the nebulae is bright enough to stimulate the cone cells, color perception is possible.
High magnification can reduce the sky brightness level enough that visual adaptation will complete. This takes time--half an hour or longer for most folks--and extraneous light sources need to be blocked. But the rod cells will eventually dominate and our ability to resolve faint extended objects is maximized. It's under these conditions that I would expect an observer's color perception to be essentially non-existent.
Regards,
Bill in Flagstaff
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Grand Canyon Adventure
Lowering the Threshold
18" Obsession
4.5" Meade 4500
10x50 Swift Audubon
Cosmic Voyage
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Starman1
Postmaster
Reged: 06/24/03
Posts: 10186
Loc: Los Angeles
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Quote:
I have just read a post in one forum and a guy said that ?we can not see any colour even with a giant scope?. But I doubt if it is true or not. Some veteran observers say that it is possible to see nebula colour through huge scopes, even small scopes. One guy claimed that the M42 that he saw was greenish.
But I feel confused at this moment. As a student who studying Biology, I have a concept that we can?t see things with colour.
Is there anyone kind enough to tell me the truth?
It totally depends on the amount of light. The greenish color of the central part of the Orion Nebula can be seen through almost any optical aid at a dark site. The peach and rose hues in the outer parts of the nebula require more aperture--say 6" with a UHC or 10-12" without. I had a chance to see the nebula without a filter through a 28" scope recently, and the fainter parts of the nebula faded from red to rose to peach shades while the brighter sections were green and blue-green. Even such over-viewed objects as the Orion Nebula can excite and surprise in enough aperture. Just awesome.
And M27 was greenish with rosy-red extensions!
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Don Pensack
12.5" Truss Dob, 5" Maksutov
Sustaining Lifetime IDA member, TeleVue junkie
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Jake Saloranta
super member
Reged: 10/04/04
Posts: 159
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Blue color in a galaxy? Bill, enlighten me, what galaxy and what aperture? M31 is yellow, but personally I've never seen blue in a galaxy, I'm intrigued.
Jake
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BillFerris
Carpal Tunnel
Reged: 07/17/04
Posts: 2435
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Quote:
Blue color in a galaxy? Bill, enlighten me, what galaxy and what aperture? M31 is yellow, but personally I've never seen blue in a galaxy, I'm intrigued.
Jake
Hi Jake,
Actually, I was seeing blue in M31 just last week with the 18-inch.
Regards,
Bill in Flagstaff
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Grand Canyon Adventure
Lowering the Threshold
18" Obsession
4.5" Meade 4500
10x50 Swift Audubon
Cosmic Voyage
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Jake Saloranta
super member
Reged: 10/04/04
Posts: 159
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Ok, I'll ask one of my mates to try it with larger apertures.
Cheers,
Jake
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Chris Graham
mmmm...Haggis
Reged: 04/01/04
Posts: 4869
Loc: Stirling, Scotland
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Quote:
I've seen color in M42 even in my town. Green is the color I see.
I usually see blue
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-Skywatcher 8" Reflector on HEQ5 with Skyscan
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matt
Vendor (Scopemania)
Reged: 07/28/03
Posts: 9633
Loc: Chaville, France
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I think that most of us must see nebulae greenish, but as it's moslty "monochrome" we often interpret it as grey.
I always see diffuse nebulae as monochrome; except perhaps M42 which has a hint of purple / pink (faint pink actually) in the brightest area in the 16"; I've seen it reported in large scopes elsewhere. A lot of the small planetary nebulae have a blue and/or green tint.
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Matt
CI700 mount with various scopes on top.
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AZDeepSky
sage
Reged: 09/19/04
Posts: 336
Loc: Tijeras, NM
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An interesting set of posts. I'd be interested in reports from the over 60 yr crowd. First, I'm just grateful to be seeing....not quite qualified for cataract surgery yet...forced to use my left rather than my dominant right eye...and the loss of at least one visual magnitude. But, even 30 years ago I never experienced what I would call a definite confirmation of color in a nebula. Hints, yeah. And always the double stars; but never the nebula. So, for those of you who are seeing colors, live it up!
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Tak-Epsilon-180ED f/2.8
SV-115 f/7 TMB design
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Edited by AZDeepSky (11/16/04 09:10 AM)
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Jake Saloranta
super member
Reged: 10/04/04
Posts: 159
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Az,
My spoken English is fine I sent you a privat message, so I won't be held responsible for spamming
And to the human eye - as far as I know - green is the first (easiest) color one can spot in DS objects, so green in M42 is pretty common. I recall once asking this in a finnish mailing list and Arto Oksanen (check out his pics, those bad boys are awesome!) replied me and told, he saw bright red colour in M42 while he was observing with the 100" NOT (Nordic Optical Telescope) scope in La Palma, Spain
Jake
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Darren
scholastic sledgehammer
Reged: 07/17/03
Posts: 885
Loc: 44N, 79W (Newmarket, Ont., Can...
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Quote:
I always see diffuse nebulae as monochrome; except perhaps M42 which has a hint of purple / pink (faint pink actually) in the brightest area in the 16"; I've seen it reported in large scopes elsewhere.
That's exactly what I saw through a friend's 10" Newt last saturday night. Just at the southern edge of the brightest section of the cloud surrounding the Trapezium, the colour was slightly pinkish.
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Clear nights ... dark sites,
Darren
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David Knisely
Postmaster
Reged: 04/19/04
Posts: 5974
Loc: Beatrice, Nebraska
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Quote:
Blue color in a galaxy? Bill, enlighten me, what galaxy and what aperture? M31 is yellow, but personally I've never seen blue in a galaxy, I'm intrigued.
Jake
I have to agree, as the only color I have seen in M31 is a sort of weak yellowish-orange in the core region (30 inch Obsession). No other galaxy showed even the slightest hint of color. Clear skies to you.
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David W. Knisely
Hyde Memorial Observatory
http://www.hydeobservatory.info
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Dave Mitsky
Postmaster
Reged: 04/08/02
Posts: 5012
Loc: Pennsylvania, USA
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While observing M42 on exceptional nights, I've seen pale green, pale blue (around the Trapezium), and muted pinks and browns (in the wings) through instruments of 14.5 inches and larger.
Some observers have seen both blue (reflection nebula portion) and pink (emission nebula portion) in M8.
Many planetaries are blue, blue-green, or green depending upon the observer's color perception and the aperture employed but IC 418 (the Raspberry Nebula) is a distinct pinkish hue through big scopes when the conditions are right.
Dave Mitsky
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Chance favors the prepared mind.
De gustibus non est disputandum.
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Ptarmigan
Carpal Tunnel
Reged: 09/23/04
Posts: 1696
Loc: Arctic
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I've seen blue galaxies, NGC 4565. Orion Nebula to me is bluish-green.
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Ptarmigans=Cute and Cuddly
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David Knisely
Postmaster
Reged: 04/19/04
Posts: 5974
Loc: Beatrice, Nebraska
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Quote:
I have just read a post in one forum and a guy said that “we can not see any colour even with a giant scope”. But I doubt if it is true or not. Some veteran observers say that it is possible to see nebula colour through huge scopes, even small scopes. One guy claimed that the M42 that he saw was greenish.
But I feel confused at this moment. As a student who studying Biology, I have a concept that we can’t see things with colour.
Is there anyone kind enough to tell me the truth?
Well, some color is visible in certain objects, but it is generally more pastel than vivid. To me, using my 10 inch without a filter, M42 appears almost sky-blue with just a hint of greenish towards the "Hygenian" region around the Trapezium. With the UHC filter, much of the nebula is an almost lime-green color. With my "funny" Lumicon OIII (with the "red leak" passband), there are faint reds visible in certain portions away from the brighter core region, although much of the nebula remains a bluish-green color. My old Lumicon H-Beta filter will also make portions of M42 appear reddish in color, although the nebula looks smaller than in any other filter. The only other deep-sky objects which I have seen red color in using only my 10 inch Newtonian are M8, IC 418 (the "Pink" planetary), and Campbell's Hydrogen star. Most of the brighter planetary nebulae have that bright bluish-green "planetary" color. Clear skies to you.
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David W. Knisely
Hyde Memorial Observatory
http://www.hydeobservatory.info
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i_sairanen
member
Reged: 10/17/04
Posts: 45
Loc: Imatra, Finland
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I have seen once color in M42. The trapezium zone was clearly red. The color was visible only with direct vision and low powers, I used a 16" dobsonian scope. I was quite amazed because I observed such poor skies as NE. lim mag 5.5. I have also seen blue and green in some planetary nebulae, mostly in the brightest ones.
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Iiro Sairanen
http://personal.inet.fi/surf/deepsky
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jwaldo
Smart Mime
Reged: 04/26/04
Posts: 3489
Loc: SoCal
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Last night I was viewing M42, it was definitely bright green, with some flashes of brown or dark red at times.
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-Jim
DHQ 8"
C102 w/ upgraded focuser
ZenithStar 66 ED Triplet
DSH 6"
Transporter 70
Sears 60/900mm
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Anonymous
Unregistered
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M42 is a slate green color in my eye, and very subtle at that. I only get the color after several minutes at the eyepeice.
I do get hints of color in globulars, but they are fleeting and my just be eye strain
I haven't seen any colors in galaxies at all.
boyd
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markf
Carpal Tunnel
Reged: 10/13/04
Posts: 1935
Loc: Houston, TX
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I saw M42 the first time last thursday. Found by accident while scanning Orion with binocs. Through them it was bluish. ONce I put the scope on it, it was greenish tint. Can't wait to get back out there and try to find other nebulas! 
Mark
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Celestron C6N on a CG5-GT
Orion 80mm Refractor (guidescope)
ToUCam Pro II
Canon Digital Rebel
http://www.carsandfish.com/astroweb
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Daniel Mounsey
Vendor
Reged: 06/12/02
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You can see color in objects if you have a big enough scope but that's not being practical. In Steve Kennedy's 24" and 28" dobs, numerous planetary nebulas are in color. You just need enough light to stimulate the cones in your eyes. If you read "Seeing In the Dark" by Timothy Ferris, he describes the Tarantula nebula at the eyepiece in a huge observatory scope and said it was brick red. But like I said before, under most viewing you rarely see color, so it just depends.
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Dave Mitsky
Postmaster
Reged: 04/08/02
Posts: 5012
Loc: Pennsylvania, USA
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Here's a list of colorful nebulae from the Starrynights Yahoogroup.
Name Const. R.A. Dec. mv Notes
NGC 7662 And 23 25.9 +42° 33' 8.3 Blue Snowball
NGC 7009 Aqr 21 04.2 -11° 22' 8.3 Saturn Nebula
NGC 40 Cep 00 13.0 +72° 31' 12.4 .
M27 Vul 19 59.6 +22° 43' 7.3 Dumbbell Nebula
NGC 6826 Cyg 19 44.8 +50° 31' 8.8 Blinking Nebula
NGC 6891 Del 20 15.2 +12° 42' 10.5 .
NGC 6543 Dra 17 58.6 +66° 38' 8.1 Cat's Eye Nebula
NGC 1535 Eri 04 14.3 -12° 44' 9.6 .
NGC 2392 Gem 07 29.2 +20° 55' 7.4 Eskimo Nebula
NGC 6210 Her 16 44.5 +23° 49' 8.8 .
NGC 3242 Hya 10 24.8 +18° 38' 7.8 Ghost of Jupiter
IC 418 Lep 05 27.5 +12° 42' 9.3 Raspberry Nebula
NGC 6369 Oph 17 29.3 -23° 46' 11.4 Little Ghost
NGC 6572 Oph 18 12.1 +06° 51' 9.1 The Emerald Nebula
M42 Ori 05 35.4 -05° 27' 4 The Great Orion Nebula
M8 Sgr 18 03.8 -24° 23' 5.8 Lagoon Nebula
M20 Sgr 18 02.6 -23° 02' 6.3 Trifid Nebula
NGC 6445 Sgr 17 49.3 -20° 01' 11.2 .
NGC 6818 Sgr 19 44.0 -14° 09' 9.3 Little Gem
Dave Mitsky
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Chance favors the prepared mind.
De gustibus non est disputandum.
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BillFerris
Carpal Tunnel
Reged: 07/17/04
Posts: 2435
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Quote:
Here's a list of colorful nebulae from the Starrynights Yahoogroup.
Name Const. R.A. Dec. mv Notes
[snip]
NGC 6826 Cyg 19 44.8 +50° 31' 8.8 Blinking Nebula
[snip]
I recently had an interesting experience with NGC 6826. The view in the new 18-inch Obsession was quite unexpected. I've seen the blinking effect, where the nebula is visible with averted vision but disappears as the the central star switches on under direct scrutiny, many times in smaller scopes. In the 18-inch, there is more of a dissolving effect. Both the central star and nebula are visible with averted vision. With direct vision, both are initially visible and the nebula dissolves away over the course of a second or two.
It's similar to blowing a puff of air to fog a window and watching as the condensations evaporates from the outside-in. I was reminded of the scenes in LOTR where Frodo dissappears after putting on the ring.
Regards,
Bill in Flagstaff
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Grand Canyon Adventure
Lowering the Threshold
18" Obsession
4.5" Meade 4500
10x50 Swift Audubon
Cosmic Voyage
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Barry Fernelius
professor emeritus
Reged: 01/28/04
Posts: 602
Loc: Rancho Santa Margarita, Califo...
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Dave Mitsky's post included:
Quote:
Name Const. R.A. Dec. mv Notes
NGC 7662 And 23 25.9 +42° 33' 8.3 Blue Snowball
...
M27 Vul 19 59.6 +22° 43' 7.3 Dumbbell Nebula
...
M42 Ori 05 35.4 -05° 27' 4 The Great Orion Nebula
M8 Sgr 18 03.8 -24° 23' 5.8 Lagoon Nebula
M20 Sgr 18 02.6 -23° 02' 6.3 Trifid Nebula
Just a few random comments. I definitely have seen the pretty blue color in NGC 7662. I see color in M42 and M8 as well.
Unless I have access to a rather large aperture instrument, I can't see color in M20 or M27 at all!
As always, your mileage may vary...
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The real voyage of discovery consists not in seeking new landscapes, but in having new eyes. -Proust
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Dave Mitsky
Postmaster
Reged: 04/08/02
Posts: 5012
Loc: Pennsylvania, USA
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Quote:
Quote:
Here's a list of colorful nebulae from the Starrynights Yahoogroup.
Name Const. R.A. Dec. mv Notes
[snip]
NGC 6826 Cyg 19 44.8 +50° 31' 8.8 Blinking Nebula
[snip]
I recently had an interesting experience with NGC 6826. The view in the new 18-inch Obsession was quite unexpected. I've seen the blinking effect, where the nebula is visible with averted vision but disappears as the the central star switches on under direct scrutiny, many times in smaller scopes. In the 18-inch, there is more of a dissolving effect. Both the central star and nebula are visible with averted vision. With direct vision, both are initially visible and the nebula dissolves away over the course of a second or two.
It's similar to blowing a puff of air to fog a window and watching as the condensations evaporates from the outside-in. I was reminded of the scenes in LOTR where Frodo dissappears after putting on the ring.
Regards,
Bill in Flagstaff
Bill,
I've noted the same phenomenon with NGC 6826 and several other planetaries that "blink".
Dave Mitsky
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Chance favors the prepared mind.
De gustibus non est disputandum.
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Anonymous
Unregistered
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it may be the blink is located on the other end of the observation continueum. In other words, the photonic destination may have a periodic obscuration rather than the point of origin 
boyd
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dlapoint
sage
Reged: 08/18/03
Posts: 300
Loc: Moncton NB Canada
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I see color in many dso's, but you need to be careful. Are you really seeing the color of the neb, or transfering the color of near by stars. In m42 for example, many back ground stars have nebulosity around them. Are you seeing |
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