sixela
Postmaster
Reged: 12/23/04
Posts: 9499
Loc: Boechout, Belgium
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Quote:
This is slightly off topic,,,please forgive. I had never heard we have poor red response (assume meant as when dark adapted) so I did some surfing. I came across an article that was very interesting. If this article is correct we're all running around with our red flashlights degrading our dark adaptation every time we turn one on.
Well, only the dark adaptation that lets us see red through the red cones. For many of the fainter objects, I think very many people have never seen colour, and the fact there is such a thing as using averted vision means that we aren't using those red cones *that* much...
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400mm f/4.46 David Lukehurst truss Dobsonian on Tom Osypowski equatorial platform
Orion Starblast (114mm f/4 reflector, Alt/Az)
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David Knisely
Postmaster
Reged: 04/19/04
Posts: 6787
Loc: Beatrice, Nebraska
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Quote:
This is slightly off topic,,,please forgive. I had never heard we have poor red response (assume meant as when dark adapted) so I did some surfing. I came across an article that was very interesting. If this article is correct we're all running around with our red flashlights degrading our dark adaptation every time we turn one on. Read and see! No pun intended  Also to see red it appears you need to look directly at what you looking at. The center of your retina is all red cones. Interesting read.
oops...forgot the link  http://www.stlplaces.com/night_vision.html
Well, I'm afraid that the article is a little inaccurate in a few areas (spelling among them). While *any* light used for chart illumination impacts night vision, *DIM* red light is still the best kind to help preserve dark adaptation. This has been fully demonstrated by a number of scientific studies (I can give a number of published references if need be). The light should be adjustable in brightness or be just barely bright enough that you see a sort of very vague reddish-brown color on a white piece of paper. If the paper looks a nice brilliant red, the light is *too* bright. Using a light much brighter than the point where you can just barely detect the reddish color on white paper can cause a signficant reduction in your dark adaptation. Even with such steps, after extended chart reading with a minimal red light, there can be a short "re-adaptation" period to get back your optimal level of night vision. Bright red lights are definitely a no-no (unless you are maybe using them for navigation as you walk around). Clear skies to you.
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David W. Knisely
Hyde Memorial Observatory
http://www.hydeobservatory.info
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Ptarmigan
Carpal Tunnel
Reged: 09/23/04
Posts: 1874
Loc: Arctic
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When I see nebulas, they are usually greenish or bluish with a tinge of gray. This is even with a large telescope I have looked through. I have seen color only in globular and open clusters.
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Ptarmigans=Cute and Cuddly
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Diego
super member
Reged: 07/29/03
Posts: 179
Loc: Argentina South America
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OK, I have also been asking about this on this board and other boards, even searching through the net if colors other than green are visible.
Don (posts as Starman) told me it is possible and that he saw pinkish hues in the "loop" area in M42 with a 90 mm scope...
Well my search is over. Last week I set up my 6" scope in the backyard and took a nice, good, long view at M42.
Color WAS visible 
It was mostly noted at 45X with an Orion 26mm Highlight Plossl. I was seeing the regular greenish color in the Trapezium region, but upon closer inspection I started to see pinkish hues in the fainter "loop" area in the nebula as Don pointed out to me.
It had always been there, right in my face and I never noticed it. The pink hues were seen with out any filtering and with direct vision. They are VERY subtle but if you look long enough and from a dark site you will see it.
For reference, my NELM is about 5.5 and probably a little deeper at zenith. If your NELM is not that deep I would recommend larger aperture if possible and higher mag. for extra contrast.
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Diego
Celestron 80 mm f11.4
Oberwerk 20x90
6" f7.8 Reflector
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Starman1
Vendor - Scope City
Reged: 06/24/03
Posts: 10962
Loc: Los Angeles
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Diego,
Congrats.
Now your mission impossible is (and the Secretary will disavow all knowledge of your actions should you be caught) to catch the different colors on each side of the "loop".
Assuming the overall shape is that of a diamond ring, with the Trapezium area the diamond, the inside of the ring is a different color on one side of the Trapezium than it is on the other.
I've seen one side as "rosy-hued" (i.e.pinkish) and the other as a shade of "peach". both of these colors are in the nebulosity inside the "ring". And you'll need a dark night with clear skies (rare, recently).
A very large scope (28") shows the bright "arcs" on either side of the Trapezium (the brightest parts of the "ring") to have a reddish glow, but I have never seen this in a scope smaller than 17.5".
The peach and rose hues I mention are seeable in your 6" from a dark site. I've seen them in 90mm, as I mentioned, but that was from an exceptionally dark site.
Good luck.
[Next summer, try for color in the Dumbbell (M27). when it's at the zenith, the "bow-tie" sometimes appears greenish, and the "football" (the fainter sections at right angles to the "bow-tie") appear rose-colored. Use a decent amount of magnification, but no filter.]
Double Good Luck!
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Don Pensack
12.5" Truss Dob, 5" Maksutov
Sustaining Lifetime IDA member, TeleVue junkie
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Diego
super member
Reged: 07/29/03
Posts: 179
Loc: Argentina South America
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Hey Don! I have to thank you for the advise. You bet I'm going to keep tryin. Now, everytime I take a peek at M42 I see more and more detail. I can't imagen what that views are like in 16" or larger instruments.
M27 sounds like a good challenge. It will be winter by then in the southern hemisphere. I've only seen it with the 80 mm, and last winter I was too cold and lazy to find it again with the 6" (although I did try) 
What about M8?
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Diego
Celestron 80 mm f11.4
Oberwerk 20x90
6" f7.8 Reflector
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Starman1
Vendor - Scope City
Reged: 06/24/03
Posts: 10962
Loc: Los Angeles
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Theoretically, M8 should be bright enough to display some color--especially for you, for whom it is high in the sky.
Some big scope users have reported seeing pinkish hues in M8, but more observers have seen some color in M20, from what I've heard. I've seen pinkish hues in the emission part of M20, though never blue hues in the reflection part.
Many planetaries display color when they are high in the sky--usually greenish or greenish-blue hues.
A Lumicon UHC filter from the '90s with the "red leak" shows the colors better on many nebulae because it filters out a lot of the frequencies that overwhelm the rosy hues that are there but often too faint to see. The recent UHC filters, though, no longer have the red passband and don't display the rose hues. That's why I recommend not using a filter on M27 (though perhaps a broadband filter might help, because primarily yellow and orange frequencies are diminished).
Yes, M42 is SO detailed I suspect it would take a lifetime to see all of its details visually. One of my favorite details is to look for the "mackerel sky" mottling in the Trapezium area. The brightest part of the nebula, under higher powers, breaks up into sections that look like a group of cotton balls wadded together, or, as Admiral Smyth stated, "like a mackerel sky", an expression from our history that describes the high clouds that seem to be broken into little round segments extending across the sky, presumably because they represent the appearance of fish scales (earlier Americans were a lot more familiar with the appearance of different fish than are modern Americans who buy all their fish pre-cut).
If you are an artist, you might try your hand at drawing what you see. This, I find, helps you see even more.
Good viewing.
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Don Pensack
12.5" Truss Dob, 5" Maksutov
Sustaining Lifetime IDA member, TeleVue junkie
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Diego
super member
Reged: 07/29/03
Posts: 179
Loc: Argentina South America
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I'll have to wait until next winter for M8. I doubt M20 will show any color with this aperture, I can barely see the 3 dark lanes...
Drawing what I see is something I've always considered doing, I just never get to it. Perhaps I should build an equatorial mount with traking.
I have tried high power on M42 to see that details you describe but the views weren't that great. Not sure if I had reached the scope's limits or if it was bad seeing. Most people will agree that bad seeing only affects planets but I suspect it can also affect DSO when searching for finer detail.
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Diego
Celestron 80 mm f11.4
Oberwerk 20x90
6" f7.8 Reflector
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jmoore
Carpal Tunnel
Reged: 10/01/03
Posts: 1959
Loc: Beaufort, NC
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I see firey reds, oranges, and purples...truly amazing...but only in the brightest objects of course...and only in scopes above 200mm aperture. 100mm is definitely too small. sounds like you guys are missing a lot.
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Hardin 12"
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Anonymous
Unregistered
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Quote:
Diego,
[Next summer, try for color in the Dumbbell (M27). when it's at the zenith, the "bow-tie" sometimes appears greenish, and the "football" (the fainter sections at right angles to the "bow-tie") appear rose-colored. Use a decent amount of magnification, but no filter.]
Hey I saw this, this past summer but it was in a 30". Was also surprised at the level of detail visible in M27 as well. After looking in the 30" scope I normally go look at the same object in my 18" just to see what detail I can tease out but I didn't do it this time, so I don't know if I would have seen color in the 18"
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Starman1
Vendor - Scope City
Reged: 06/24/03
Posts: 10962
Loc: Los Angeles
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Your post reminds me of this from the 1960's:
"Ever since the sun took LSD, it's been a fundamentally better sun--more red, more blue, more green. Here it comes now. Bwoooooooooppp!
Oh, no! Paisley again!"
I love tongue-in-cheek posts, though sometimes it's hard to tell.........
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Don Pensack
12.5" Truss Dob, 5" Maksutov
Sustaining Lifetime IDA member, TeleVue junkie
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jmoore
Carpal Tunnel
Reged: 10/01/03
Posts: 1959
Loc: Beaufort, NC
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Quote:
Your post reminds me of this from the 1960's:
"Ever since the sun took LSD, it's been a fundamentally better sun--more red, more blue, more green. Here it comes now. Bwoooooooooppp!
Oh, no! Paisley again!"
Is this an excerpt taken from your journal, Don?
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Hardin 12"
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Amalia
Reged: 10/16/04
Posts: 5165
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I have seen the outer part of M42 in kind of a salmon rose. It was very easy to be seen. I did not believe my eyes, that's why I did not write it until today. But as I got it confirmed from two sides, here is how to do:
I had a longer Moon observation of about an hour. When the Moon went down, I immediatly switched over to M42. There was this very obvious rose (pink? I remember it as "salmon") colour.
It seems the colour sensitive parts of my eyes got stimulated by the bright Moon light, so I was able to see the colour.
Amalia
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jmoore
Carpal Tunnel
Reged: 10/01/03
Posts: 1959
Loc: Beaufort, NC
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Amalia...and you said (in a whisper) that I didn't know the secret. schade.
ok...maybe I joke about the fiery reds and purples, but yes, after various sorts of "pre-stimuli" to the eyes, I've also seen deceptively reddish hues in objects like M42. This happened to me last night in fact. It was a nice trick.
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Hardin 12"
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Diego
super member
Reged: 07/29/03
Posts: 179
Loc: Argentina South America
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I recall reading about a technique to see color such as you describe. It said that viewing a bright object like the moon stimulated our "color see cells" instead of only relying on "night vision cells"...
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Diego
Celestron 80 mm f11.4
Oberwerk 20x90
6" f7.8 Reflector
Edited by Diego (01/19/05 10:19 PM)
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Amalia
Reged: 10/16/04
Posts: 5165
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Yeah!
I can't wait to repeat this experience as it was so beautiful.
I have read that looking into a normal flashlight would give the same result. But "somehow" I prefer the Moon... 
Amalia
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Amalia
Reged: 10/16/04
Posts: 5165
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Quote:
ok...maybe I joke about the fiery reds and purples, but yes, after various sorts of "pre-stimuli" to the eyes, I've also seen deceptively reddish hues in objects like M42. This happened to me last night in fact. It was a nice trick.
There are lots of tricks, Jeff.
I can report on how one can save all the scopes and stuff - and see coloured stars all the same:
It happened to me when I got too fast out of the car and hit my head on the car's roof: Very coloured stars even on daytime.... 
Amalia
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sixela
Postmaster
Reged: 12/23/04
Posts: 9499
Loc: Boechout, Belgium
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Quote:
Amalia...and you said (in a whisper) that I didn't know the secret. schade.
ok...maybe I joke about the fiery reds and purples, but yes, after various sorts of "pre-stimuli" to the eyes, I've also seen deceptively reddish hues in objects like M42.
I doubt they're deceptive. I think what happens is that you dark-unadapt back closer to the rod/cone break while viewing the moon and see less "grey" from the rods when you then look at M42. You'd probably see less filaments, but what you'd see would be more coloured.
It probably only works for fairly bright objects -- I think the results if you tried it on a galaxy is that you'd just see one "colour": black.
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400mm f/4.46 David Lukehurst truss Dobsonian on Tom Osypowski equatorial platform
Orion Starblast (114mm f/4 reflector, Alt/Az)
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jmoore
Carpal Tunnel
Reged: 10/01/03
Posts: 1959
Loc: Beaufort, NC
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Quote:
There are lots of tricks, Jeff.
I can report on how one can save all the scopes and stuff - and see coloured stars all the same:
It happened to me when I got too fast out of the car and hitted my head on the car's roof: Very coloured stars even on daytime....
Amalia
Yes, I try to not use this one very often. 
jm
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Hardin 12"
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Amalia
Reged: 10/16/04
Posts: 5165
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Me, too!
But I'll have to try it again, because I forgot to watch in which constellation these stars were.  
Amalia
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