Smallest scope you've seen red in Orion nebula?

[JoeBlow]

I've observed the Orion Nebula many times before, but I have never really looked for colour, so I've only noticed green previously. Last night I had a look with my 6" reflector and unexpectedly saw a very distinct red tinge. The inner region was bright bluish-green and the outer parts had a distinct red tinge.

And this was under less than ideal conditions! There was some very light cloud cover over Orion, the moon was just above the horizon and I was observing from my home in an outer suburb of Sydney (dark orange on the light pollution map), plus only 6 inches of aperture.

I wonder if my eyes are extra sensitive to red? What has been the smallest telescope that others here have seen red in the Orion Nebula?

[CAAD9]

Hi Joe,

I've looked at the Orion Nebula with my 14" dob and only ever saw grey. Where you using a filter by any chance?

My brother in law felt he saw a hint of red in the Tarantula nebula in my 14 one time ( I didn't see it) and Nasa_pete once told me he saw red in the Tarantula as well but that was through an 18" dob.

I'm intrigued, I'll have to have a closer look next dark sky trip. Let us know if you used any filters. Being a galaxy fan I don't have any filters I'd be keen to hear any recommendations.

Thanks in advance.

Adam

[skysurfer]

One word: Impossible. Period.

Human eyes are not sensitive to Halpha at low intensities. Otherwise one can see colors in Eta Carinae and even the North America nebula.

The 'red' you 'see' is just wat you want to see, but actually it is monochrome bluish green as only the rods in the eye are activated.

Using a larger scope does not increase surface brightness as a larger scope won't allow using low magnifications: one is stuck to 1/6x per mm of aperture.

[janoskiss]

I've only ever seen it greenish in the ASV's 25" Obsession.

[raymo]

As a young man, MANY years ago, I could see a definite green tint in M42
virtually any time, using a 5" Newt. As the years passed I first needed a 6" and then an 8", and now need a 10" to see even the slightest trace of green; I suppose in a few years [if I'm still around] I'll need a 12".
You can still use very low magnification with a largish scope if it has a
low enough focal ratio.
raymo

[mental4astro]

Colour perception is a totally individual thing. It has something to do with aperture, but only to a point. You, as an individual, may see colour in M42, you may see soft pinks and bluish-greenish tinges, like you did Joeblow, or only ever greys no matter how large the aperture is.

In males, colour blindness is the norm rather than the exception. This can go from so very mild to totally no colour perception at all (very rare). And the 'blindness' is commonly seen as confusing complimentary colours, like red and green (most common), blue and orange, yellow and violet.

Your age & health are other factors in vision acuity and colour perception/sensitivity. And if you have been on the turps too before using your scope, that is a very big factor. Intoxication from booze, drugs, and some medicines, all impact on vision.

When I first got my 17.5" dob nearly ten years ago, one of the first objects I looked at was also M42, from my backyard in Sydney. I was also able to see soft pinks & bluish-greens in it then. Today, even from a dark site, I can only see mild soft bluish-greens with the same scope. Would a larger aperture show me pinks again - I have my doubts, but maybe. I can only try and find out.

Now, women folk, colour blindness is VERY rare. I would love to hear from women on their experiences with their perception of colour in M42. THAT would be most interesting to find out.

How vivid the colouration is would always be mild though, even for those with excellent colour perception.

Colour perception is very critical in some professions, such as prosthetics, where one task is to match the colouration of a person's features, such as eyes, teeth, skin, etc (prosthetic mechanical properties aside). Then to complicate matters in colour matching is metamerism which is the apparent change in colour due to the change in quality of incident light. Normal flouro light has a green bias, incandescent lights yellow, UV often in night clubs - all of these can alter the way colours are reflected back from different materials. The military too can have very tight requirements on colour perception.

Keep in mind though, that colour blindness has nothing to do with light sensitivity, especially low light. Which is a great thing with astro, :)

[Atmos]

I struggle to see the star colours in the Jewel Box through a 10" SCT, I don't remember seein anything other than grey in M42 through any scope other than my old 16" dob.
I am only 27 but I know my eye sight isn't the best and I know that I am a bit colour blind. I see the entire spectrum but it is akin to only have thousands of colours rather than millions (using old computer terminology). Years ago my mother asked me to help match some pearls (match size, shape and colour), she told me not to bother after 15 minutes as apparently some of the greens weren't even close haha

[75BC]

This is a topic I was going to post about but didn’t as I felt I may be scoffed at. ;)

About 7 years ago I went down to Nannup in South Western Australia for a week holiday and took my 10” dob. It either rained or was clouded out the entire week except for 1 night, for about an hour when it cleared. Crystal clear sky, no wind at all. Had a look at Jupiter and it was dazzeling. So bright.

Then I looked at M42. At first I thought I was seeing things. I could see colour in it. All I had read up to then was that this was not possible. I kept looking away from the eyepiece and back again and there it was. Not a lot, but definitely there. The main body of the nebula was tinged green, but most impressively was the area where the wings protrude from, and their edges, were a definite reddish purple.

I only had about 15 minutes viewing it with my partner before the clouds came back. I put it down to the extraordinary conditions on that night. That was the best 15 minutes of observing I’m ever likely to have.

[gary]

That is incorrect because I myself perceive pale greens and shades of
pale magenta within M42 and veins of pink within the Homunculus
itself of Eta Carina. :)

I've observed it apertures as little as 8". In the case of M42, a wide
field eyepiece that frames the whole object I find makes the colors
more noticeable. This is likely no coincidence.

For a long time I simply assumed that the perception of color in these
objects was self evident to most with younger eyes, but anecdotally
I have come to appreciate not everyone perceives it.

Color, of course, is not a phenomena inherent in physics, but instead a
function of the eye and the brain.

The hypertensive rods can also play a part in color perception.

We know from many different types of experiments that the way humans
process and perceive different colors is very different to how
man-made technologies such as cameras work.

If human color perception was based on a simple RGB model like that in
a digital camera, then there are a series of wonderful experiments that
provide counterintuitive results and break that model.

For example, consider the work of Edwin Land, of Polaroid fame, and John
McCann and Jeanne Benton in the 60's and 70's. Three of the great
pioneers of modern colour theory.

In one experiment they found if you illuminated a scene with
a narrow band source at 550nm and at a level just enough to trigger
the rods but not the cones, and you also illuminated the same scene
with a narrow band source at 656nm at a level enough to stimulate the
long wavelength cones but not the middle wave length cones, then
test subjects would perceive the scene with a remarkable range of
color including reds, yellows, browns, blue-greens, grays and blacks.

In classical color theory as many of us were taught in science class at
school, the rods aren't supposed to be involved in color perception at all.

The same classical theory would tell us that at 656nm, with only the
long wave length cones firing, the scene would be predominantly in
shades of red.

For those of us who can perceive a range of colors within M42, it
is likely that both the rods and at least one set of cones are firing.

Best Regards

Gary Kopff
Mt Kuring-Gai

[CAAD9]

Gee, hasn't this turned into a great thread?

Alexander's post makes a lot of sense, and actually Atmos' post stirred a memory: when I was in my early 20s I had a Tasco 4" or 4.5" newt, and I remember the Jewel box being one of my favourite if not the favourite targets. It was vivid with colour. I loved it. I don't recall ever seeing colour in orion.

Fast forward 20 years of the Tasco collecting dust, I acquire a 10" then a 14" and I'm DSO hunting every few days:D... But the jewel box is a bitter disappointment.

I have been putting it down to open clusters not being good targets in the bigger scopes. But realistically with the 35mm Panoptic, the magnification would be on par with the 20mm in the old newt and besides the TVs all have better True fov, light transmission etc etc. I can't do a side by side comparison as I gave the Tasco away on the eve of acquiring the 10", but now come to think of it perhaps the lack of colour may well be the fact that I'm in my mid 40s. :sadeyes: this would confirm Alex's point about male vision.

Luckily for me my night vision is as good as ever. I can see the deep fuzzies pretty well.

Cheers all.

P.s. Great post Colin , I love stories of those magic moments.:thanx: still great post Colin, but I had actually meant to reference Brendon's post here not Colin's. My bad

[Atmos]

Some people are far more colour sensitive than others so I have no doubt that some may see a reasonable amount of colour in some bright DSOs with modest aperture; I know I am not one of them :)

This is in part what draws me more to astrophotography over purely visual.

[CAAD9]

Yeah, Gary must be one of the lucky few with colour. I'm lucky to be able to see structure in distant galaxies, I know not everyone can.

Cheers all.

Jupiter will have a double moon transit soon. Must drag the 14" dob out. Clouds be damned, they're not stopping me!

[Allan]

I see green and blue in lots of objects, but that's where the human eye is most sensitive anyway, so many people experience the same thing. I have always struggled to see red in anything. But I just spent a week observing with some 32" dobs and I saw red in many of the planetary nebula we observed. So aperture rules when it comes to seeing colour.

[JoeBlow]

I don't think it's impossible, in fact numerous people have claimed to see red in the Orion nebula.

The first time I noticed it I wasn't even looking for colour and it had been a while since I last saw a photo of the Orion nebula. When I got back inside the first thing I did was look up photos of the nebula and the colours matched very well with what I saw.

Other than planetaries, I haven't seen colour in any other extended nebula though.



That's close to what I can see. The brighter inner part has always been an obvious bluish-green colour even with a 60mm refractor.


Recently I tried a number of online colour acuity and contrast tests, I scored perfectly in all of them. However I'm not sure how accurate an online colour test is.

I found this test particularly difficult:

http://wvw.igame.com/eye-test/ but still got a perfect score of 29

[Atmos]

I have done a lot of different online colour tests and I usually fail both kinds. There are the ones to test to see whether you have good colour vision (I fail) and ones to say that I have bad colour vision (I fail). This is what leads me to believe that I am not colour blind BUT not a complete spectrum.

I got 24 on my first shot on that test btw.

[JoeBlow]

I got 29 with no incorrect answers on my first go. I retried the test a number of times (its different every time) and have now scored as high as 33, which is odd since 29 is the highest score they have on their chart.


Edit: The test keeps going until you run out of time or select too many incorrect answers.

[CAAD9]

My best was 19. I. Found the best way was to see it when it clicked over so I suspect that was just me gaming it. Once the colours set in with more than 6x6 i was mostly lost particularly with the darker blues. Averted vision rescued me a few times. Interesting test.

[Kunama]

My tired 59 year old eyes scored 26 on first try.
I took my 18" F5.5 scope to a CAS event and had a queue of about 15 people viewing through it at M42. All but 3 people saw the blue/green colour. One young lady who had not looked through a scope before described the view " Wow, I love the blue green and red areas" I asked her to expand and she described the nebula in almost photographic detail. I wish I had her eyesight.
Personally I see the colour only in the big scope, my CN212 comes in grey scale.

[pluto]

I've observed M42 on a few occasions under dark skies through my 120mm f5 refractor and I see a blue/grey centre with purpleish outer. I was very surprised to see any colour the first time I observed it as I'd never seen any colour in anything else I'd observed before (not that that's too much as I'm not much of a visual observer). I've never seen any green in it though and I see more saturation in the purple than the blue - which is basically just a cool grey colour.