Return to the Cloudy Nights Telescope Reviews home pageAstronomics discounts for Cloudy Nights members
· Get a Cloudy Nights T-Shirt · Submit a Review / Article

Click here if you are having trouble logging into the forums

Privacy Policy | Please read our Terms of Service | Signup and Troubleshooting FAQ | Problems? PM a Red or a Green Gu… uh, User

General Astronomy >> Beginners Forum

Pages: 1 | 2 | 3 | 4 | (show all)
Atl
professor emeritus
*****

Reged: 04/13/12

Color in Orion
      #5534920 - 11/23/12 06:35 AM

I am new to observing. I was out tonight with my 12" Dob. Normally Orion is a colorless fan shaped cloud. Tonight after a few hours viewing I went to Orion. In the center was cobalt blue, and the edges of the fan were very pink. I had my wife look at it but she saw no color. Every time I looked the color was unmistakable. Is this my imagination? Why couldn't my wife see it? I also noticed more detail than any other viewings, and it seemed larger.

Post Extras: Print Post   Remind Me!   Notify Moderator  
edwincjones
Close Enough
*****

Reged: 04/10/04

Re: Color in Orion new [Re: Atl]
      #5534927 - 11/23/12 07:01 AM

I have seen, in a 36", magnificent dark reds that look like cotton candy;
but no color in smaller scopes

edj


Post Extras: Print Post   Remind Me!   Notify Moderator  
Tapio
Pooh-Bah


Reged: 09/24/06

Loc: Tampere, Finland
Re: Color in Orion new [Re: edwincjones]
      #5534939 - 11/23/12 07:20 AM

Lucky you if you saw color.
Your wife probably didn't have dark adapted eyes like you.


Post Extras: Print Post   Remind Me!   Notify Moderator  
bigstormgirl
super member


Reged: 01/02/12

Loc: NW Indiana
Re: Color in Orion new [Re: Atl]
      #5534940 - 11/23/12 07:20 AM

You mentioned you were out for a few hours viewing. I'm sure your eyes were very well adapted to the dark, and if the seeing conditions were good, you did see color. Was your wife out with you all night too? If she wasn't, her eyes may have not been adapted when she looked through the eyepiece.

Post Extras: Print Post   Remind Me!   Notify Moderator  
Achernar
Postmaster
*****

Reged: 02/25/06

Loc: Mobile, Alabama, USA
Re: Color in Orion new [Re: Atl]
      #5534971 - 11/23/12 07:59 AM

It's not your imagination, people can and do see color in the Orion Nebula through larger telescopes from very dark sites when they are very well dark adapted. Your wife possibly wasn't as well dark adapted as you, or her vision at night isn't the same as yours. I never have seen color in M-42 other than a greenish tinge, but I have seen nebulosity spilling out of the field of view in all directions through my 10 and 15-inch. You certainly had a very clear transparent sky and no interference from either the moon or light pollution. The fact you have very good vision at night doesn't hurt either.

Taras


Post Extras: Print Post   Remind Me!   Notify Moderator  
REC
Post Laureate
*****

Reged: 10/20/10

Loc: NC
Re: Color in Orion new [Re: Achernar]
      #5535020 - 11/23/12 08:41 AM

Sometimes I think I might see subtle hints of color on a night with excellent transparency with a wide angle EP with a nebula filter from a dark site.

Welcome to Cloudy Nights!


Post Extras: Print Post   Remind Me!   Notify Moderator  
cheapersleeper
Post Laureate
*****

Reged: 01/22/10

Loc: Sachse TX
Re: Color in Orion new [Re: Achernar]
      #5535021 - 11/23/12 08:42 AM

On one odd cold morning I saw the nebula as light green through a 6" newt. It was unmistakeably green. I have never seen it so colorful since using apertures up to 12".

B


Post Extras: Print Post   Remind Me!   Notify Moderator  
jfaust75
professor emeritus


Reged: 10/04/11

Loc: Central Florida
Re: Color in Orion new [Re: cheapersleeper]
      #5535189 - 11/23/12 10:21 AM

I usualy see blue and pink and sometimes green through the 8".

Post Extras: Print Post   Remind Me!   Notify Moderator  
David PavlichAdministrator
Transmographied
*****

Reged: 05/18/05

Loc: Mandeville, LA USA
Re: Color in Orion new [Re: jfaust75]
      #5535233 - 11/23/12 10:46 AM

There is definately a touch of green there.

David


Post Extras: Print Post   Remind Me!   Notify Moderator  
GlennLeDrew
Postmaster
*****

Reged: 06/18/08

Loc: Ottawa, Ontario, Canada
Re: Color in Orion new [Re: jfaust75]
      #5535258 - 11/23/12 11:03 AM

Blue-green should be the dominant color, as the O-III doublet and H-beta emission lines happen to fall pretty much right at the peak of sensitivity of the eye. Red is more doubtful, as the eye's sensitivity to the H-alpha line is perhaps 5-10% of that at the mid spectrum (and less when dark adapted.)

One need not be well dark adapted to see the greenish color of such a bright nebula as the inner region of M42; the surface brightness is just about as high as any nebulosity can get.

The only red I'd credit the possibility to detect would have to be in or near this brightest central region, in order that the surface brightness be high enough to activate the retina's cones. And then the red must 'compete' with the more readily seen and vusually dominant green. In the outer parts of the nebula the surface is just too low to detect the red. It's well known that in even colorless glows the visual system tends to perceive the brighter and dimmer parts as greenish and reddish, respectively. Of course, the great familiarity we have gained from innumerable color images must at least on a subconscious level lead to bias. I don't recall observations from the age of visual observtions prior to color imaging which reported unambiguous detection of reds in nebulae like we find today. And the instrument is not a factor here; the poorer system transmissions in the days of old were not sufficiently bad to make that much of a difference at all.

Through a 16" I've managed to detect a hint of red in the Huygenian region of M42. It was subtle at best, what with the preponderance of those pesky greenish photons flooding the view. But red outside that region? Not for me.


Post Extras: Print Post   Remind Me!   Notify Moderator  
Jon Isaacs
Postmaster
*****

Reged: 06/16/04

Loc: San Diego and Boulevard, CA
Re: Color in Orion new [Re: GlennLeDrew]
      #5535310 - 11/23/12 11:35 AM

Quote:

But red outside that region? Not for me.




The workings of the eye are rather complicated, I offer no explanations...

After only seeing the green for the past 20 years or so, in the past year, viewing the Orion Nebula from a dark site with my 12.5 inch, 16 inch and 25 inch scopes using exit pupils of about 3mm-4mm, I often see the central region as "electric green" and the "wings" as a faint, rust red.

It might be that the red is merely result of the brain's processing the image, that the red results from it being a complimentary color to the green.

I do question the need for a fully dark adapted eye since dark adaptation does not improve one's color vision, I suspect a fully dilated eye which only takes a moment that is in the process of adapting might be best suited for seeing color. In my experience bright nebulae like NGC6572, the Blue Racketball show the most color when there is some bright light (the moon works well) around. Earlier this year while viewing for a normally dark site with a nearly full moon, NGC6572 appeared more intensely green than I had previously seen it. It remained green at high magnifications (small exit pupils) in scopes both large and small..

Jon


Post Extras: Print Post   Remind Me!   Notify Moderator  
thetortoise
super member
*****

Reged: 07/25/12

Loc: Longmont, CO
Re: Color in Orion new [Re: Jon Isaacs]
      #5535894 - 11/23/12 05:19 PM

Interesting to see different perspectives on the color ranging from colorless to various different colors. I see the Orion Nebula as absolutely green, every time. I have never seen reds or pinks in it and I look at it anytime it's in the sky.

Post Extras: Print Post   Remind Me!   Notify Moderator  
Dave Mitsky
Postmaster
*****

Reged: 04/08/02

Loc: PA, USA, Planet Earth
Re: Color in Orion new [Re: thetortoise]
      #5535911 - 11/23/12 05:29 PM

The topic of seeing color in deep-sky objects has been discussed a number of times on Cloudy Nights.

Scotopic (night) vision is essentially color blind.

http://www.visualexpert.com/Resources/nightvision.html

http://www.schorsch.com/en/kbase/glossary/scotopic-vision.html

Be that as it may, under excellent conditions I have on a number of occasions seen blue and green shades in the area around the Trapezium and a brownish-red hue in M42's wings through large aperture Dobs from dark sites.

Dave Mitsky


Post Extras: Print Post   Remind Me!   Notify Moderator  
csrlice12
Postmaster
*****

Reged: 05/22/12

Loc: Denver, CO
Re: Color in Orion new [Re: Dave Mitsky]
      #5535921 - 11/23/12 05:34 PM

Or could it all be chaulked up to red/green colorblindness????

Post Extras: Print Post   Remind Me!   Notify Moderator  
JohnMurphyRN
sage
*****

Reged: 09/09/12

Loc: Near St Louis
Re: Color in Orion new [Re: csrlice12]
      #5535932 - 11/23/12 05:40 PM

Looks green/blue to me...

Post Extras: Print Post   Remind Me!   Notify Moderator  
Tom and Beth
Post Laureate


Reged: 01/08/07

Loc: Tucson, AZ
Re: Color in Orion new [Re: Atl]
      #5535956 - 11/23/12 05:58 PM

With a 10 inch scope and a bit of power, I see......

A Bork...with a little Color around the edges.


Post Extras: Print Post   Remind Me!   Notify Moderator  
jeff heck
Pooh-Bah
*****

Reged: 01/16/06

Loc: stl,mo.
Re: Color in Orion new [Re: Tom and Beth]
      #5536105 - 11/23/12 07:09 PM

I could make out no color on M42 with the 10", with the 16" I see a pale green tint. Others looking thru the 16" report pink, blue and green. Last week I was trying for the G and H stars when at 385x the E and F stars took on a burnt orange color. This is the first time I have seen this. No luck with the faint G and H stars.

Post Extras: Print Post   Remind Me!   Notify Moderator  
BigC
Carpal Tunnel
*****

Reged: 09/29/10

Loc: SE Indiana
Re: Color in Orion new [Re: Atl]
      #5536129 - 11/23/12 07:29 PM

Quote:

I am new to observing. I was out tonight with my 12" Dob. Normally Orion is a colorless fan shaped cloud. Tonight after a few hours viewing I went to Orion. In the center was cobalt blue, and the edges of the fan were very pink. I had my wife look at it but she saw no color. Every time I looked the color was unmistakable. Is this my imagination? Why couldn't my wife see it? I also noticed more detail than any other viewings, and it seemed larger.


Congratulations on such a fantastic sight!I do believe you.I have good reason to know and understand everyone's eyesight is not the same.

The Orion Nebula is one of my favorite objects .Usually it just looks gray,and very rarely a faint rose.The extent of the nebula grows the longer I am out viewing so that it is well beyond the FOV of my modest plossls even the 25mm. Several nights this fall have been very good with the nebula as large or larger than I had seen it ,yet no color ,though it looked three-dimensional more so than in previous years.Viewed this fall with scopes of 5 (Bushnell Mak)to 12 ( Z12) inches and always striking appearance.

I think you must be lucky and have sensitive color vision.


Post Extras: Print Post   Remind Me!   Notify Moderator  
Atl
professor emeritus
*****

Reged: 04/13/12

Re: Color in Orion new [Re: BigC]
      #5536278 - 11/23/12 09:16 PM

Well, I will be out around 3am Arizona time. I will see if it repeats. If it does then I am content that red light and color can be seen by dark adapted eyes.

Post Extras: Print Post   Remind Me!   Notify Moderator  
omahaastro
sage


Reged: 08/30/06

Loc: Omaha, NE
Re: Color in Orion new [Re: Atl]
      #5536304 - 11/23/12 09:32 PM

I get pinkish hues in my 18/30" scopes... confirmed by others.

Post Extras: Print Post   Remind Me!   Notify Moderator  
orion61

*****

Reged: 10/20/07

Loc: Birthplace James T Kirk
Re: Color in Orion new [Re: omahaastro]
      #5536469 - 11/23/12 11:47 PM

I am thinking it may be a bit of both, mostly wishfull thinking, I have very good acuity and with a 16" scope I could see a strong shift to the green side and the faintest hint of pink but I was hoping as much as seeing..
But as long as you are out there and excited is enough...Your mind can play some amazing tricks when desire is high enough...


Post Extras: Print Post   Remind Me!   Notify Moderator  
Atl
professor emeritus
*****

Reged: 04/13/12

Re: Color in Orion new [Re: orion61]
      #5536699 - 11/24/12 07:05 AM

OK...just got in. With a 90mm mak I get a white cloud and with a 12" dob I am still getting the blue center and pink outlying areas with maybe a hint of green. I am guessing it to be real. I also get pink in the flame and horsehead nebulas. I can't resolve any real details, but the dim nebulosity (did I invent that word?) is tinged with pinkness.

Post Extras: Print Post   Remind Me!   Notify Moderator  
Achernar
Postmaster
*****

Reged: 02/25/06

Loc: Mobile, Alabama, USA
Re: Color in Orion new [Re: Atl]
      #5536956 - 11/24/12 10:09 AM

I never have seen pinks in IC-434. Once I was looking at it through a very large telescope with a H-beta filter, and the nebula looked reddish. Of course the Horsehead was there too, like a black horse. I only seen it this way once, from a very dark location.

Taras


Post Extras: Print Post   Remind Me!   Notify Moderator  
BigC
Carpal Tunnel
*****

Reged: 09/29/10

Loc: SE Indiana
Re: Color in Orion new [Re: Atl]
      #5536997 - 11/24/12 10:41 AM

Seeing the Horsehead is a feat,with color is astounding!No wonder scepticism is being expressed.

I remember there was a German girl who was able to recognize people at much greater than the usual distance;this was tested and verfied. Much rarer than one in a million.


Post Extras: Print Post   Remind Me!   Notify Moderator  
Atl
professor emeritus
*****

Reged: 04/13/12

Re: Color in Orion new [Re: BigC]
      #5537076 - 11/24/12 11:22 AM

I didn't see the horse head I just saw a mistiness in that area...I could not discern the horse itself. Locating it is simple...but seeing the horse is impossible for less than an 18" I am told.

Post Extras: Print Post   Remind Me!   Notify Moderator  
Dave Mitsky
Postmaster
*****

Reged: 04/08/02

Loc: PA, USA, Planet Earth
Re: Color in Orion new [Re: Atl]
      #5537127 - 11/24/12 11:53 AM

B33 has been detected as a notch in IC 434 through H-beta-filtered giant binoculars by reliable observers.

http://www.cloudynights.com/item.php?item_id=2594

A number of people have seen it through small refractors.

I've observed the Horsehead Nebula through filtered 8" and 10" Dobs and on a few occasions without filters through larger Dobs. It was a rather easy target through Tom Clark's 42" Beast from the Chiefland Astronomy Village a couple of years ago.

Dave Mitsky


Post Extras: Print Post   Remind Me!   Notify Moderator  
Atl
professor emeritus
*****

Reged: 04/13/12

Re: Color in Orion new [Re: Dave Mitsky]
      #5537143 - 11/24/12 12:06 PM

Is a hydrogen beta worth the purchase? Does it make that big a difference?

Post Extras: Print Post   Remind Me!   Notify Moderator  
Atl
professor emeritus
*****

Reged: 04/13/12

Re: Color in Orion new [Re: Atl]
      #5537175 - 11/24/12 12:26 PM

I am answering my own question. Here is a performance test of major filter types on nebula. Very good article.
http://www.prairieastronomyclub.org/resources/by-dave-knisely/filter-performa...


Post Extras: Print Post   Remind Me!   Notify Moderator  
GlennLeDrew
Postmaster
*****

Reged: 06/18/08

Loc: Ottawa, Ontario, Canada
Re: Color in Orion new [Re: Atl]
      #5537207 - 11/24/12 12:57 PM

If one is seeing any color at all in such an excessively low surface brightness glow as IC434, which is so far below the color detection threshold as to be impossible for any human who ever lived (I will boldly claim ), then one is definitely experiencing an illusory effect. And by extension, reports of red in other of the lower surface brightness nebulosities (including the outer parts of M42) are suspect.

Post Extras: Print Post   Remind Me!   Notify Moderator  
David Knisely
Postmaster
*****

Reged: 04/19/04

Loc: southeastern Nebraska
Re: Color in Orion new [Re: Atl]
      #5537260 - 11/24/12 01:42 PM

Quote:

Is a hydrogen beta worth the purchase? Does it make that big a difference?




Yes, it can help a lot in seeing the Horsehead. It is best used in larger apertures, but can help for a few objects in smaller ones. It isn't the best filter for nebulae in general, but for the Horsehead, the California, Barnard's Loop, and some other faint targets, it is a real game changer. Clear skies to you.


Post Extras: Print Post   Remind Me!   Notify Moderator  
jfaust75
professor emeritus


Reged: 10/04/11

Loc: Central Florida
Re: Color in Orion new [Re: GlennLeDrew]
      #5537266 - 11/24/12 01:45 PM

I couldnt chime in on IC434 as ive never seen horsehead or flame except in pictures, but as far as m42 goes i definately see blue and green in my 8" even from a not so dark site(maybe not the pink or any other red....thats probably my imagination)

Post Extras: Print Post   Remind Me!   Notify Moderator  
MikeBOKC
Post Laureate
*****

Reged: 05/10/10

Loc: Oklahoma City, OK
Re: Color in Orion new [Re: jfaust75]
      #5537310 - 11/24/12 02:21 PM

In a conversation this weekend with a very very experienced observer with far more eyepiece time than I will ever log he used a term I had not heard before, but which was perfect for this thread -- "averted imagination." Sometimes our desire to see something very dim and vague is such that we THINK we see it where it is supposed to be. I would put the horsehead near the top of the averted imagination list. Nothing wrong with that of course -- the hunt is a big part of the fun.

Post Extras: Print Post   Remind Me!   Notify Moderator  
omahaastro
sage


Reged: 08/30/06

Loc: Omaha, NE
Re: Color in Orion new [Re: MikeBOKC]
      #5537317 - 11/24/12 02:24 PM

Although I think we're getting off topic... the original account was of color within IC434 (which personally, I've never seen any hint of).

Post Extras: Print Post   Remind Me!   Notify Moderator  
Atl
professor emeritus
*****

Reged: 04/13/12

Re: Color in Orion new [Re: GlennLeDrew]
      #5537425 - 11/24/12 03:50 PM

Quote:

If one is seeing any color at all in such an excessively low surface brightness glow as IC434, which is so far below the color detection threshold as to be impossible for any human who ever lived (I will boldly claim ), then one is definitely experiencing an illusory effect. And by extension, reports of red in other of the lower surface brightness nebulosities (including the outer parts of M42) are suspect.




Actually the reading I have done on this supports seeing color with large diameter scopes of good quality...which I have. I have also noted that several manufacturers of large dobs make this claim also. Color sensitivity is highly individual.


Post Extras: Print Post   Remind Me!   Notify Moderator  
jfaust75
professor emeritus


Reged: 10/04/11

Loc: Central Florida
Re: Color in Orion new [Re: omahaastro]
      #5537429 - 11/24/12 03:51 PM

Quote:

Although I think we're getting off topic... the original account was of color within IC434 (which personally, I've never seen any hint of).




No, the OP was an account of color in M42 the IC434 came much later in the thread.


Post Extras: Print Post   Remind Me!   Notify Moderator  
Atl
professor emeritus
*****

Reged: 04/13/12

Re: Color in Orion new [Re: jfaust75]
      #5537432 - 11/24/12 03:53 PM

Also note I am not claiming brilliant flashing colors in the nebula...just a tinge...

Post Extras: Print Post   Remind Me!   Notify Moderator  
jfaust75
professor emeritus


Reged: 10/04/11

Loc: Central Florida
Re: Color in Orion new [Re: Atl]
      #5537448 - 11/24/12 04:01 PM

Im hoping it stays clear tonight so i can look again to be positive of what i am seeing in M42. my memory may be playing some of the color up, but I do believe i seethe core as an electric blue with green spreading out of the core. I am also not claiming to see this huge nebulosity spilling out of my FOV with a huge amount of color(but black and white with grey not at all what im seeing)

Post Extras: Print Post   Remind Me!   Notify Moderator  
Meadeball
sage


Reged: 10/22/12

Loc: Midlothian, Virginia
Re: Color in Orion new [Re: jfaust75]
      #5537571 - 11/24/12 05:24 PM

Being no opthalmologist, I do remember from my school years that the retina uses its cone-shaped cells that deliver color in daylight, and reverts over to the rods that deliver better sensitivity but no color at night.

That said, could it be possible that Atl's seeing conditions (and aperture) delivered such a bright view of M42 that some of the cones became active and were able to discern a tinge of color? If he only claimed this once we could all just say it was wishful thinking or "mind games," but since he "waxed scientific" and performed a test using his 90mm Mak and found he was seeing no color there yet his claimed colors remained in the Dob, I'm supportive of the possibility that this could occur.

Now, I just wish it would happen to me. My deep-sky universe has always been the same shade of gray-green.

Meade

Edited by Meadeball (11/24/12 05:25 PM)


Post Extras: Print Post   Remind Me!   Notify Moderator  
faackanders2
Carpal Tunnel


Reged: 03/28/11

Re: Color in Orion new [Re: Atl]
      #5537581 - 11/24/12 05:34 PM

Quote:

I am new to observing. I was out tonight with my 12" Dob. Normally Orion is a colorless fan shaped cloud. Tonight after a few hours viewing I went to Orion. In the center was cobalt blue, and the edges of the fan were very pink. I had my wife look at it but she saw no color. Every time I looked the color was unmistakable. Is this my imagination? Why couldn't my wife see it? I also noticed more detail than any other viewings, and it seemed larger.




Most don't see color unless they have large dobs, very dark site, and well dark adapted eyes for large pupils (hence maybe younger also).

First time I have seen color in M42 (besides blue from OIII filter) was in a webster 24" dob.

I have seen red lagoon nebula in my 17.5" dob but only from a very dark site.


Post Extras: Print Post   Remind Me!   Notify Moderator  
faackanders2
Carpal Tunnel


Reged: 03/28/11

Re: Color in Orion new [Re: Atl]
      #5537595 - 11/24/12 05:43 PM

Quote:

OK...just got in. With a 90mm mak I get a white cloud and with a 12" dob I am still getting the blue center and pink outlying areas with maybe a hint of green. I am guessing it to be real. I also get pink in the flame and horsehead nebulas. I can't resolve any real details, but the dim nebulosity (did I invent that word?) is tinged with pinkness.




Pink from the horsehead? I coulds just barely see this in my 17.5" with extremely well dark adjusted eyes (no red flashlights and no looking at any far away strret lights from a very dark site in rural area,


Post Extras: Print Post   Remind Me!   Notify Moderator  
faackanders2
Carpal Tunnel


Reged: 03/28/11

Re: Color in Orion new [Re: Atl]
      #5537598 - 11/24/12 05:48 PM

Quote:

Is a hydrogen beta worth the purchase? Does it make that big a difference?




I have rarely used my hydroge3n beta filter with my 17.5".
Might have used it more if my Astrocrum filter slide could accomodate 4 filters instead of 3. Definitely get narroband Ultrablock and OIII first, wideband skyglow nezt, before buying H-beta.


Post Extras: Print Post   Remind Me!   Notify Moderator  
GlennLeDrew
Postmaster
*****

Reged: 06/18/08

Loc: Ottawa, Ontario, Canada
Re: Color in Orion new [Re: faackanders2]
      #5537694 - 11/24/12 07:01 PM

It's important to realize that no telescope can increase the surface brightness of an extended object beyond that seen by the unaided eye. In fact, because of whatever light losses occur, a telescope always presents an image having somewhat reduced surface brightness, even when the exit pupil is maximal.

Another important fact is that moving closer to an extended object does not increase its surface brightness. If you traveled 100X closer to M42, it would appear 100X larger, but its surface brightness will jot have changed. Yes, due to its now 10,000X greater angular area it will have a *total* brightness 10,000X greater, but again, the surface brightness is no different.

Once an object of given surface brightness has been enlarged enough to perceive color, further increases in aperture, which allow greater magnification for given exit pupil, will not necessarily make the color any easier to see. More detail will be seen of course, but the surface brightness will not increase and so color 'strength' will be the same.

Naturally, the more area an object subtends on the retina, the greater the *total* brightness, which does have a considerable impact. And to some degree, for those threshold objects color wise, a considerable size should help. But if the surface brightness places color detection below human perception, *no amount of aperture whatsoever* can make color magically appear.


Post Extras: Print Post   Remind Me!   Notify Moderator  
Atl
professor emeritus
*****

Reged: 04/13/12

Re: Color in Orion new [Re: GlennLeDrew]
      #5537771 - 11/24/12 08:02 PM

That's true, but if that threshold is reached then it can be percieved. Have you got concrete data on what the threshold is for all humans?

Post Extras: Print Post   Remind Me!   Notify Moderator  
jfaust75
professor emeritus


Reged: 10/04/11

Loc: Central Florida
Re: Color in Orion new [Re: Atl]
      #5537808 - 11/24/12 08:34 PM

So does this mean you can't see color or not? Because I certainly see color in the core(not seeing color in the nebula though)

Post Extras: Print Post   Remind Me!   Notify Moderator  
jmandell
sage


Reged: 06/15/11

Re: Color in Orion new [Re: jfaust75]
      #5537931 - 11/24/12 10:09 PM

There was one night last year that I saw a hint of pink on the edges with my 12", but it was the best conditions I have ever observed in and I was well dark adapted. I have seen the nebula throught a 25" many times ( from darker skies) but have seen only blue and green.

Congrats on seeing red. It is a truly memorable sight.


Post Extras: Print Post   Remind Me!   Notify Moderator  
HfxObserver
Pooh-Bah
****

Reged: 11/12/04

Loc: Regina, SK, Canada
Re: Color in Orion new [Re: jmandell]
      #5538058 - 11/24/12 11:44 PM

Having viewed shades of burgundy, white & blue in M42 using a 5-inch refractor the 12-inch reflector a friend has confirms the hints I see. Through a 20-inch even on a mediocre night with Orion just rising these colours are readily apparent.

-Chris


Post Extras: Print Post   Remind Me!   Notify Moderator  
jfaust75
professor emeritus


Reged: 10/04/11

Loc: Central Florida
Re: Color in Orion new [Re: HfxObserver]
      #5538129 - 11/25/12 12:55 AM

just came in and my memory mustve added to my description....im going with green overall(no blue this time)

Post Extras: Print Post   Remind Me!   Notify Moderator  
David Knisely
Postmaster
*****

Reged: 04/19/04

Loc: southeastern Nebraska
Re: Color in Orion new [Re: omahaastro]
      #5538155 - 11/25/12 01:22 AM

Quote:

Although I think we're getting off topic... the original account was of color within IC434 (which personally, I've never seen any hint of).




Neither have I (even in some fairly large apertures). IC 434 is just a little too faint to show much other than the darkness of the Horsehead's inclusion. However, M42 is definitely a different story. Unfiltered, it has always looked a sort of very pale sky bluish to me except for the Huygenian region around the Trapezium and fishes mouth, where the color is dominated by a bluish-green hue. Filtered, the view gets a little more "saturated" with respect to the colors seen. With most narrow-band nebula filters that do not have any secondary passbands, most of M42 that does show color appears as a saturated bluish-green hue. In the OIII filter, the hue is more greenish, but still bluish-green. However, there was one filter where my first experience with "red" became something I would remember for a long time. In the mid to late 1980's, I picked up a Lumicon OIII filter which a friend of mine (astrophotographer Rick Johnson) had recommended I get. We were out observing together one late fall evening when I put my 10 inch on M42. What I saw astounded me, as some of the brighter portions did show a very dim but quite definite reddish hue. I called Rick over and he too saw the red. He put his 10 inch with his OIII on M42, but with his setup, he failed to see that red. We were puzzled until we looked at each of our Lumicon OIII filters with a red light. My filter passed red but Rick's did not. We mentioned this to Jack Marling at Lumicon and he asked for the filters back to make detailed measurements on them. It turns out that mine had a whopping "red leak" secondary passband that Rick's OIII didn't, which kind of explained why I was seeing red and Rick wasn't able to. This kind of convinced me that the red was indeed quite real. I can put my old OIII and my new one that does not have the red secondary passband in a filter switch and actually see the faint reds in M42 appear and then vanish as I switch filters.

Similarly, my DGM Optics NPB narrow-band filter also has a nice big secondary red passband. In my 14 inch f/4.6 Newtonian at around 52x to 79x, the NPB shows some faint pinkish or reddish hues mainly in the brighter regions surrounding the more bluish-green Huygenian area and in the brighter portions of the two "wings" of the nebula. For comparison, I can put in my Orion Ultrablock narrow-band filter or my new Lumicon UHC, both of which do not have any red transmission. With those two filters, there is absolutely no red seen. Some people have trouble seeing the reds in nebulae, and I can fully understand this, as some do not have a lot of red sensitivity at lower light levels with their eyes. However, as for me, my personal "tests" have convinced me that what I am seeing is not an illusion, but real color. Clear skies to you.


Post Extras: Print Post   Remind Me!   Notify Moderator  
GlennLeDrew
Postmaster
*****

Reged: 06/18/08

Loc: Ottawa, Ontario, Canada
Re: Color in Orion new [Re: David Knisely]
      #5538552 - 11/25/12 11:21 AM

David's experience with filters on M42 brings up an interesting point. A filter designed to block the majority of light outside a narrow bandpass at the O-III and h-beta lines, but which by accident or design happens to allow the deep red light of H-alpha through as well, can help to better bring out the red in those parts having sufficient surface brightness. But of course, that red which is so visually low in intensity is still having to 'compete' with the quite dominant blue-green emission.

How to eliminate that 'offending' blue-green? Try an H-alpha filter, which is normally used only for imaging. A narrow bandpass type is somewhat better than a dyed cut-off type, as it will more thoroughly eliminate non H-alpha wavelengths. But any deep red filter which passes some 90% or more of the 656nm wavelength will be educational.

Now the challenge is just *seeing* any nebulosity at all. If it appears red, it may or may not be illusory. Because the other, much higher surface brightness wavelengths have been suppressed, the surface brightness of all parts will have been reduced quite remarkably, with only the very brightest part(s) seen at all. Yet to a camera (sensitive to H-alpha), the red is usually the dominant color most everywhere. This exercise will drive home just how awful is the human eye at seeing red.

Try this with other emission nebulae, too. Those having moderate to dim surface brightness, as seen without filtration, through a red filter will not be seen at all. Most certainly IC434! Even when the dominant emission line is H-alpha. In the case of such hydrogen-dominant nebulae as IC434, the California and others, the weaker H-beta line is much more prominent to our eyes. If color were to be seen, it should be at least primarily blue-green, not red.

The surface brightness threshold for color detection is estimated by me as about 19 magnitudes per square arcsecond. But this must certainly vary somewhat with color and its saturation, or 'purity.' Celestial objects are viewed through our atmosphere, which from even pristine locales has its own color from airglow emission. As object surface brightness gets lower, its light becomes dominated by atmospheric light. For example, a reasonably dark sky of surface brightness 21 MPSAS is 3 magnitudes, or 16 times brighter than a nebula such as the North America, which in these conditions can be seen in an unfiltered 10X50 binocular by an experienced observer. Which source do you suppose might provide the stringest color to the view, the nebula itself or the rather brighter sky? And do not forget that the nebula appears brighter than the surrounding sky only because the two sources add together. The nebula's feeble light makes it and the foreground sky together appear to be 6% brighter than the sky itself.


Post Extras: Print Post   Remind Me!   Notify Moderator  
Meadeball
sage


Reged: 10/22/12

Loc: Midlothian, Virginia
Re: Color in Orion new [Re: GlennLeDrew]
      #5538962 - 11/25/12 03:26 PM

Well, it would seem that if we *are* seeing shades of green (and we can detect the colors passed by a myriad of filters), then our cone cells are indeed operating in dim light conditions. And if they're operating, they're certainly able to detect other colors as well -- provided those wavelengths are strong enough. Personal performance probably varies, so ... ?

I hope y'all aren't treating this as an argument; I'm finding it incredibly interesting. Pity we don't have an opthalmologist astronomer in here!

Meade

Edited by Meadeball (11/25/12 03:27 PM)


Post Extras: Print Post   Remind Me!   Notify Moderator  
GlennLeDrew
Postmaster
*****

Reged: 06/18/08

Loc: Ottawa, Ontario, Canada
Re: Color in Orion new [Re: Meadeball]
      #5539047 - 11/25/12 04:25 PM

When different colors are present, the resulting color we see depends on the relative intensity. For any given image point, its color results from an admixture. The more dominant any particular wavelength, the more strongly the perceived color shifts to it. And so what red there is to be seen must 'fight' to get through the much more easily perceived blue-green.

Photographically, the vast majority of emission nebulae are red dominant, but visually the red contributes essentially nothing. One does not find on offer visual H-alpha filters for a good reason; in only a tiny handful of all nebulae (including planetaries, of which Campbell's Hydrogen Star is a standout example) can any red be detected, and mostly with difficulty.

The eye's poor red response, the visual dominance of other colors, the low surface brightness of most nebulae in the first place, and the light of the sky itself all conspire to make visual red detection in all but a few exceptionally bright examples impossible. Bias borne of familiarity with color images must to some extent be operating nowadays, else how to account for the lack of such reports in pre-color photography times, when even meter class and larger instruments were peered into? And knowing the numbers regarding the relative contributions of the light sources involved, and the human visual response, only reinforces this. It's so very easy to color the imagination with a combination of illusion and bias.

The $64 question is: Can the variation in color sensitivity among individuals amount to something of an order of magnitude, or a factor of ten? Specifically, can some enjoy a tenfold increase above the norm in red sensitivity? For that's about what it would take to permit red detection at all near to that claimed.


Post Extras: Print Post   Remind Me!   Notify Moderator  
Jon Isaacs
Postmaster
*****

Reged: 06/16/04

Loc: San Diego and Boulevard, CA
Re: Color in Orion new [Re: GlennLeDrew]
      #5539327 - 11/25/12 07:48 PM

Quote:


The $64 question is: Can the variation in color sensitivity among individuals amount to something of an order of magnitude, or a factor of ten? Specifically, can some enjoy a tenfold increase above the norm in red sensitivity? For that's about what it would take to permit red detection at all near to that claimed.




A few thoughts:

- While informative, I think this thread is beyond the experience and reach a beginner. Any colors detected or perceived in nebulae are subtle at best.

- It is probably worth distinguishing between actually detecting a color and perceiving/seeing that color. The assumption here seems to be that perceiving/see red means that one was detecting a red color... I suggest that the fact that something appears red, particularly in the presence of other other colors, does not mean that it actually is red. The eye-brain is an amazing image processor but it is not fool proof.

Jon


Post Extras: Print Post   Remind Me!   Notify Moderator  
Meadeball
sage


Reged: 10/22/12

Loc: Midlothian, Virginia
Re: Color in Orion new [Re: Jon Isaacs]
      #5539480 - 11/25/12 10:00 PM

Let me sum everything up to date ...

M42 is FREAKIN' GORGEOUS!!!



Edited by Meadeball (11/25/12 10:01 PM)


Post Extras: Print Post   Remind Me!   Notify Moderator  
dan_h
Carpal Tunnel


Reged: 12/10/07

Re: Color in Orion new [Re: GlennLeDrew]
      #5539506 - 11/25/12 10:17 PM

Quote:

When different colors are present, the resulting color we see depends on the relative intensity. For any given image point, its color results from an admixture. The more dominant any particular wavelength, the more strongly the perceived color shifts to it. And so what red there is to be seen must 'fight' to get through the much more easily perceived blue-green.

Photographically, the vast majority of emission nebulae are red dominant, but visually the red contributes essentially nothing. One does not find on offer visual H-alpha filters for a good reason; in only a tiny handful of all nebulae (including planetaries, of which Campbell's Hydrogen Star is a standout example) can any red be detected, and mostly with difficulty.

The eye's poor red response, the visual dominance of other colors, the low surface brightness of most nebulae in the first place, and the light of the sky itself all conspire to make visual red detection in all but a few exceptionally bright examples impossible. Bias borne of familiarity with color images must to some extent be operating nowadays, else how to account for the lack of such reports in pre-color photography times, when even meter class and larger instruments were peered into? And knowing the numbers regarding the relative contributions of the light sources involved, and the human visual response, only reinforces this. It's so very easy to color the imagination with a combination of illusion and bias.

The $64 question is: Can the variation in color sensitivity among individuals amount to something of an order of magnitude, or a factor of ten? Specifically, can some enjoy a tenfold increase above the norm in red sensitivity? For that's about what it would take to permit red detection at all near to that claimed.




Once about five years ago I was looking at M42 in late spring and there was very vivid pink coloring around the outer portions. And this was with my 120mm refractor. I have looked at this object many times, often in much larger scopes than mine, and I have never seen any colors other than the often stated blue/green glow in the centre. I was amazed to see the pink when I did. It was as colorful as a photograph.

I have come to believe that what I saw was an atmospheric affect of some sort and did not represent the true color of M42. I am open to other explanations. It sure was pretty and captured my imagination for a number of days.

dan


Post Extras: Print Post   Remind Me!   Notify Moderator  
Meadeball
sage


Reged: 10/22/12

Loc: Midlothian, Virginia
Re: Color in Orion new [Re: dan_h]
      #5539511 - 11/25/12 10:20 PM

OMG ... it's the CHEMTRAILS!!!!

Edited by Meadeball (11/25/12 10:47 PM)


Post Extras: Print Post   Remind Me!   Notify Moderator  
Dave Mitsky
Postmaster
*****

Reged: 04/08/02

Loc: PA, USA, Planet Earth
Re: Color in Orion new [Re: Jon Isaacs]
      #5540419 - 11/26/12 02:28 PM

Quote:


A few thoughts:

- While informative, I think this thread is beyond the experience and reach a beginner. Any colors detected or perceived in nebulae are subtle at best.

- It is probably worth distinguishing between actually detecting a color and perceiving/seeing that color. The assumption here seems to be that perceiving/see red means that one was detecting a red color... I suggest that the fact that something appears red, particularly in the presence of other other colors, does not mean that it actually is red. The eye-brain is an amazing image processor but it is not fool proof.

Jon




While I agree in principle with the above, it should be stated that seeing colors, ranging from blue to green, in some of the brighter planetary nebulae such as NGC 3242, NGC 6543, NGC 6572, and NGC 7662 is not at all difficult, particularly through larger apertures. In fact, the nicknames of some of them are indicative of that fact, e.g., the Emerald Nebula and the Blue Snowball. No acquired observing skills are required.

Seeing color in M42 can be a bit harder. It's even more difficult for emission nebulae like M8 but on a couple of occasions I've detected a pale pink hue through 30" plus scopes. I've also seen color in Campbell's Hydrogen Star, IC 418 (the Raspberry Nebula), and Eta Carinae's Homunculus Nebula.

I'm fully aware of the argument about the ability to perceive ruddy hues in M42 as being due to visual contrast effects. What I don't understand, if that's the case, is why the only times that I have been able to do so have been when large apertures were employed at very dark sites under exceptionally good conditions. I typically don't see any color at all in M42 from light-polluted locales, even when using a dome-enclosed 17" telescope.

Dave Mitsky


Post Extras: Print Post   Remind Me!   Notify Moderator  
Jon Isaacs
Postmaster
*****

Reged: 06/16/04

Loc: San Diego and Boulevard, CA
Re: Color in Orion new [Re: Dave Mitsky]
      #5540454 - 11/26/12 02:49 PM

Quote:

I'm fully aware of the argument about the ability to perceive reddish hues in M42 as being due to visual contrast effects. What I don't understand is why the only times that I have been able to do so have been when large apertures were employed at very dark sites under exceptionally good conditions. I typically don't see any color at all in M42 from light-polluted locales, even when using a dome-enclosed 17" telescope.

Dave Mitsky




Dave:

Seeing color in bright planetary's is relatively straightforward. One of my favorites is the NGC 6572, the Blue Racketball which looks green to me. I suspect that a bit of light pollution actually helps seeing color, the greenest I have seen it was from a typically dark site but with at least the first quarter moon.

The red I see in M42 does take dark skies and a reasonable sized telescope... But I suspect that I am not actually detecting red photons but rather some complimentary eye/brain effect.

Jon


Post Extras: Print Post   Remind Me!   Notify Moderator  
Dave Mitsky
Postmaster
*****

Reged: 04/08/02

Loc: PA, USA, Planet Earth
Re: Color in Orion new [Re: Jon Isaacs]
      #5540546 - 11/26/12 03:42 PM

Jon,

A careful reading of my first paragraph reveals that I said the same thing. It's important for beginners to know that some deep-sky objects do indeed exhibit color. As far as NGC 6572 is concerned, I prefer the nickname the Emerald Nebula.

Can anyone explain then why this eye/brain effect only seems to happen under certain conditions?

Dave Mitsky


Post Extras: Print Post   Remind Me!   Notify Moderator  
cadfour
super member
*****

Reged: 07/26/12

Loc: Melbourne, Florida
Re: Color in Orion new [Re: omahaastro]
      #5540687 - 11/26/12 05:18 PM

I observed M42 (Orion Nebula) on Saturday. I saw blue..with a hint of green....am I the crazy one?

Post Extras: Print Post   Remind Me!   Notify Moderator  
Starman1
Vendor (EyepiecesEtc.com)
*****

Reged: 06/24/03

Loc: Los Angeles
Re: Color in Orion new [Re: cadfour]
      #5544069 - 11/28/12 03:20 PM

There are two issues at play, with M42:
1) lab studies show that when 2 gray squares, illuminated to *barely* the limit of scotopic vision, but one a tiny bit brighter than the other, are presented to the observer, we all see the fainter one as "reddish" or "pinkish" and the brighter one as "greenish". This alone says we should trust our eyes very little when used at or near the limits of vision, if color is seen.
That we all see it is NOT a sign the color is there, merely that all of us have eyes that work the same way.

2) when observing M42 (and heaven knows I've looked at this nebula with 2" to 60" aperture at least a thousand times over the years), sometimes more colors than simply greenish-gray or pinkish-gray present themselves.
It seems that, on those nights, the nebula is SO bright in the telescope that a quick glance away from the scope shows that night vision has been damaged.
And the range of colors seen extends to yellowish-beige, bluish, pinkish, purplish, reddish, mauves, and simple grays, and nearby NGC1977 appears quite blue. One such night, I drew a simple map of the nebula, indicating where I saw each color, and compared it to a color photograph of the nebula, and found I had correctly indicated where each shade was found. So I am certain that, under the right conditions, colors can be seen in the Orion nebula. My vision at the time was probably mesopic, and not purely scotopic.

3) But these colors are not ALWAYS visible. As an experiment, I tried viewing the nebula through an H-alpha filter. Only the brighter sections could be seen, and the brightest part, even in H-a, was the central region.
When using a filter that transmits H-b and O-III, the entire nebula can be seen. That's not surprising since every nebula that emits H-a also emits H-b at a lower level, and because our peak sensitivity at night hovers around 500nm (near the H-b wavelength).

4) Recently, I've had a chance to compare narrowband filters that have substantial transmission at H-alpha with those that have zero transmission shorter than 700nm.
It may very well be that the restriction of bandwidth creates a greater ability to see the reddish colors than a non-filtered view, because the non-filtered view didn't present them as strongly. Or that the diminishment in brightness of the entire field resulted in that red/green illusion at the limit. How to tell?
It appears the reds I am used to seeing must be real, because they are visible in the filters WITH H-a transmission, but disappear with the filters that do not have H-a transmission.

5) Different observers have different sensitivities to colors, but it seems that on the nights where I see many colors, or very strong colors, so does everyone else in the observing site, and with a wide variety of apertures. I did not record particulars about the observations, but a memory search recalls that these were nights of exceptional transparency (very low extinction) and darkness.

So what can you say about the visibility of colors in M42/M43/NGC1977?
--it varies from person to person
--it varies from night to night
--it varies according to the filter used
--it varies by aperture (the reds were stronger in larger aperture)
--if "at the limit", the colors may not be real.

But if you have a night where you can see ANY tint to the fainter interior of the nebula, looks at those sections on either side of the central region and see if one side appears yellower than the other. If you see that, I believe you are seeing REAL colors in the nebula. Just don't expect to see them all the time.


Post Extras: Print Post   Remind Me!   Notify Moderator  
magic612
Post Laureate
*****

Reged: 09/30/08

Loc: S. of Chicago's light dome
Re: Color in Orion new [Re: Starman1]
      #5544106 - 11/28/12 03:36 PM

I see a wide range of colors in M42, and it follows what Don concluded above: It varies. For me, and on the best of nights, I see the following in these scope sizes:

70mm refractor: Hints of blue, mostly gray
90mm refractor: A bit more blue, mostly gray
114mm reflector: Quite a bit of blue, the rest gray
130mm reflector: A lot of blue, some green, the rest gray
150mm reflector: Lots of blue, lots of green, some gray
250mm reflector: Blue, green, some orange, and a hint of dusty rose, the remainder gray

Those are on the best nights, and my eyes only. My kids see more color than me in smaller scopes; my wife sees less. I have asked other people to detail what they see, and it varies by person, quite widely.


Post Extras: Print Post   Remind Me!   Notify Moderator  
nirvanix
Carpal Tunnel


Reged: 06/07/07

Loc: Saskatoon, SK
Re: Color in Orion new [Re: magic612]
      #5547639 - 11/30/12 06:28 PM

On a night of excellent transparency after observing for several hours I could see hints of dusty pink in M42...and lots of green of course. So yes, I think you saw what you saw and good for you!

Post Extras: Print Post   Remind Me!   Notify Moderator  
Atl
professor emeritus
*****

Reged: 04/13/12

Re: Color in Orion new [Re: Starman1]
      #5547951 - 11/30/12 10:03 PM

Quote:

There are two issues at play, with M42:
1) lab studies show that when 2 gray squares, illuminated to *barely* the limit of scotopic vision, but one a tiny bit brighter than the other, are presented to the observer, we all see the fainter one as "reddish" or "pinkish" and the brighter one as "greenish". This alone says we should trust our eyes very little when used at or near the limits of vision, if color is seen.
That we all see it is NOT a sign the color is there, merely that all of us have eyes that work the same way.

2) when observing M42 (and heaven knows I've looked at this nebula with 2" to 60" aperture at least a thousand times over the years), sometimes more colors than simply greenish-gray or pinkish-gray present themselves.
It seems that, on those nights, the nebula is SO bright in the telescope that a quick glance away from the scope shows that night vision has been damaged.
And the range of colors seen extends to yellowish-beige, bluish, pinkish, purplish, reddish, mauves, and simple grays, and nearby NGC1977 appears quite blue. One such night, I drew a simple map of the nebula, indicating where I saw each color, and compared it to a color photograph of the nebula, and found I had correctly indicated where each shade was found. So I am certain that, under the right conditions, colors can be seen in the Orion nebula. My vision at the time was probably mesopic, and not purely scotopic.

3) But these colors are not ALWAYS visible. As an experiment, I tried viewing the nebula through an H-alpha filter. Only the brighter sections could be seen, and the brightest part, even in H-a, was the central region.
When using a filter that transmits H-b and O-III, the entire nebula can be seen. That's not surprising since every nebula that emits H-a also emits H-b at a lower level, and because our peak sensitivity at night hovers around 500nm (near the H-b wavelength).

4) Recently, I've had a chance to compare narrowband filters that have substantial transmission at H-alpha with those that have zero transmission shorter than 700nm.
It may very well be that the restriction of bandwidth creates a greater ability to see the reddish colors than a non-filtered view, because the non-filtered view didn't present them as strongly. Or that the diminishment in brightness of the entire field resulted in that red/green illusion at the limit. How to tell?
It appears the reds I am used to seeing must be real, because they are visible in the filters WITH H-a transmission, but disappear with the filters that do not have H-a transmission.

5) Different observers have different sensitivities to colors, but it seems that on the nights where I see many colors, or very strong colors, so does everyone else in the observing site, and with a wide variety of apertures. I did not record particulars about the observations, but a memory search recalls that these were nights of exceptional transparency (very low extinction) and darkness.

So what can you say about the visibility of colors in M42/M43/NGC1977?
--it varies from person to person
--it varies from night to night
--it varies according to the filter used
--it varies by aperture (the reds were stronger in larger aperture)
--if "at the limit", the colors may not be real.

But if you have a night where you can see ANY tint to the fainter interior of the nebula, looks at those sections on either side of the central region and see if one side appears yellower than the other. If you see that, I believe you are seeing REAL colors in the nebula. Just don't expect to see them all the time.




Awesome...well informed and written post.


Post Extras: Print Post   Remind Me!   Notify Moderator  
Pages: 1 | 2 | 3 | 4 | (show all)


Extra information
14 registered and 30 anonymous users are browsing this forum.

Moderator:  WOBentley, kkokkolis 

Print Thread

Forum Permissions
      You cannot start new topics
      You cannot reply to topics
      HTML is disabled
      UBBCode is enabled


Thread views: 2124

Jump to

CN Forums Home


Cloudy Nights LLC
Cloudy Nights Sponsor: Astronomics