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Aperture required to see the color of Ring Nebula

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#101 quazy4quasars

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Posted 20 October 2019 - 10:52 PM

Our ability to see color lies within the cones of our eyes, which are more centrally located and responsible for our daylight vision. This is why we can see color during the day or on very bright objects (like planets) at night.

 

The rods in our eyes is what gives us a very limited night vision. We can detect faint DSO's using "averted" vision...i.e. - getting the faint light to hit the offset rods of our eyes). We are not nocturnal creatures (astronomers notwithstanding wink.gif) and so our night vision has not developed to where the cones of our eyes can pick up much (if any) color at night or when viewing dim DSO's no matter big we make them via magnification. The cones of our eyes cannot detect much beyond subtle blues/greens and perhaps a slight bit of yellow (blue + yellow = green) under low light levels. 

 

This is simply a matter of how our eyes are designed and not a "lack" in our equipment, and aperture will not change how our eyes are designed. Camera sensors however are not designed like our eyes, which is why you see so much more red/yellow in photos that we cannot detect visually only. I'm suspect of anyone who can see red/orange on any DSO. You might "see" it only because you expect it, not because you actually are. The brain is an even more fascinating piece to the optical equation.

 

We should be quite happy to see those faint fuzzies in any kind of detail, or color beyond gray. 

 

Read this...

Read Roger S. Clarke's  Visual astronomy of the deep sky and compare the light levels of Broad Sunlit Day to that of a cloudy night devoid of moon.

 

I can navigate such a night in deep forest. Maybe I can't hunt furry rodents under such low light levels, but I can see as well as our early ancestors did- well enough to flee or to defend themselves against night-hunting predators, as our ancestors must have also done to survive.

 

It's true that scotopic rod vision robs us of color data, but you don't need to see the color of a lion to know it's a big cat.

 

Also, note that, while adding blue to paint to yellow paint does make a green paint; (mixing pigments is "subtractive combinination" by definition) - adding yellow light(green and red cones) to blue light (blue cones) makes white (or a more saturated hue: i.e.  red+blue+green cones) as with the RGB colors of a video display screen(additive combination).  This is the reason we never see green stars- there is always additive combination with a lot of blue and/or red light; usually with a fair to large amount of both: i.e. we see lots of yellow-white /white /blue-white stars.    

 

We can see gas flourescing in a high vacuum in outer space. We can see "dead" Galaxies a billion light years away; So what if we can't see fine detail well enough to read a newspaper or a star-map at light levels less than 1 Quadrillionth of daylight levels? Yes, it's dim!  But, by far the the blackest night sky you'll never see is the blackness behind those bright streetlights in the Walmart Parking lot.  

 

Human eyes are not quite as good as those of night-hunting cats, but our primate ancestors eyes evolved to make effective use of extreme low light levels, and with practice and usage, a dark starry night sky is not a barrier to our dark adapted (eye-brain) sight  the hardware is there, but it must re-learn to interpret those very weak signals..

 

When the power was out here least week, I could see in every room in my home by the light of ONE centrally located candle, with ease.  I actually loved the way things looked in that dim warm darkness. 


Edited by quazy4quasars, 21 October 2019 - 11:48 AM.


#102 Ships&Stars

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Posted 23 October 2019 - 02:21 PM

Ha, must be a Scottish thing to the OP from Forres - I'm outside of Aberdeen. For what it's worth, first time using a 20" dob under Bortle 2 with no preconception of what colour M57 'should' be, when I slewed over, I instantly got a faint but distinct blueish-green hit (more of a vivid blue) from the nebula and thought to myself for a split second - 'wow, the **** thing is blue!', but after that with direct vision, nothing but grey.

 

Perhaps it was imagination, but again no expectations or preconceptions.

 

I'd briefly read before that outside of M42, even in a big scope don't expect any colour from DSOs, so I never did! That's what caught me so off guard that night when I saw M57 in blue. 

 

Perhaps there is some chemistry going on with the eyes/rods/cones when quickly slewing over to a relatively bright DSO like M57 after being dark adapted? Anyway, I saw blue for a split second when slewing over quickly in a 20" dob. No mistake. Whether it was some trickery with eye chemistry or scope movement, eyepiece (TV or Leica that night), I really got a blue 'hit'.

 

Just my 2p.  



#103 j.gardavsky

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Posted 23 October 2019 - 03:16 PM

Ha, must be a Scottish thing to the OP from Forres - I'm outside of Aberdeen. For what it's worth, first time using a 20" dob under Bortle 2 with no preconception of what colour M57 'should' be, when I slewed over, I instantly got a faint but distinct blueish-green hit (more of a vivid blue) from the nebula and thought to myself for a split second - 'wow, the **** thing is blue!', but after that with direct vision, nothing but grey.

 

Perhaps it was imagination, but again no expectations or preconceptions.

 

I'd briefly read before that outside of M42, even in a big scope don't expect any colour from DSOs, so I never did! That's what caught me so off guard that night when I saw M57 in blue. 

 

Perhaps there is some chemistry going on with the eyes/rods/cones when quickly slewing over to a relatively bright DSO like M57 after being dark adapted? Anyway, I saw blue for a split second when slewing over quickly in a 20" dob. No mistake. Whether it was some trickery with eye chemistry or scope movement, eyepiece (TV or Leica that night), I really got a blue 'hit'.

 

Just my 2p.  

This may be due some mesopic residual in your vision at the start of the observing session. I take it as you are describing it.

 

The Great Orion Nebula

I have seen it in my young times in the mountains during the skiing holidays, and it has been pale green even with unaided eyes.

Admitted, I have been hiking about 300 height meters in a slope with deep snow,

a very good training to get my blood circulated.

 

Last time, I have been surprised to see the M42 in grey/blue color through the 6" F/5 with some orthos mounted. Not expecting any color on that observing session, as I have wanted to dissect some details inside, an have not been looking for "ephemeral" colors.

On the same night, I have also got the best view on the difficult Sh2-278 nebula in western Orion, which is even not included in the IDSA atlas.

 

Best,

JG


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#104 Ships&Stars

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Posted 23 October 2019 - 04:03 PM

This may be due some mesopic residual in your vision at the start of the observing session. I take it as you are describing it.

 

The Great Orion Nebula

I have seen it in my young times in the mountains during the skiing holidays, and it has been pale green even with unaided eyes.

Admitted, I have been hiking about 300 height meters in a slope with deep snow,

a very good training to get my blood circulated.

 

Last time, I have been surprised to see the M42 in grey/blue color through the 6" F/5 with some orthos mounted. Not expecting any color on that observing session, as I have wanted to dissect some details inside, an have not been looking for "ephemeral" colors.

On the same night, I have also got the best view on the difficult Sh2-278 nebula in western Orion, which is even not included in the IDSA atlas.

 

Best,

JG

Hi JG and thanks - yes it was at the very start of the observing session - M57 is usually my 'warmup' object before I move on to other sights so I shall look into the mesopic aspect. I've not seen Sh2-278 yet at all! Sounds like you have some good memories. One of the best skies I have ever observed was in the very SW corner of Ireland about 15 years ago about 10km outside of a small place called Allihies. There was no rain for almost two weeks and the Milky Way was so bright I slept with my head outside the tent, much to the amusement of the small handful of other campers nearby. I will try for Sh2-278 this season.

 

Cheers!


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#105 GOLGO13

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Posted 05 November 2019 - 10:07 AM

I observed it 14 years ago in a 30 inch F3.3 and remember telling my friend I saw color change in the ring compared to other scopes. I believe he saw it as well.  It was subtle but certainly there. I was younger back then and maybe that helped.

 

The Blue Snowball is blue in my scopes in light pollution. Even my 4 inch refractor. And some other planetary nebulas show color. The Blue Snowball in my friends 16 inch (same night as above) was just like photos I have seen. Blue and looks like the number 3 backwards. So it was a bit zoomed in. I observed the blue snowball in my 10 inch at higher power the other night and it was light blue and I could barely make out the backwards 3. It's one of my favorite objects.

 

but I distinctly remember some color in the Ring. It was a green zone but a pretty dark sky and a very good night with a very large scope.



#106 NorthernlatAK

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Posted 05 November 2019 - 01:29 PM

I am beginning to notice that I see colors in these dsos when I am not fully dark adapted. I looked at m57 a couple of months ago and got a warm color on the outside edge and I was observing not too far from a street light. Other times I have seen color in it the ground was covered in snow so therefore I was not able to fully dark adapt. This may be key to helping see the colors if you are physiologically able to.
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#107 GOLGO13

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Posted 05 November 2019 - 02:46 PM

Dark adaption with colors is a thing for sure. True for double stars like Alberio as well. 



#108 grif 678

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Posted 05 November 2019 - 08:51 PM

I remember this ad very well, the old Odyssey telescopes in the 80's Astronomy magazine. They had the 8 inch, 10 inch, 13 inch, 17 inch, and the 29 inch. In the details on each scope, the 13 inch was able to see several colors in many of the nebula.



#109 Araguaia

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Posted 14 November 2019 - 08:12 AM

All I can say is that there seem to be many people out there who would not be able to pick out a ripe tomato from a bin of almost-ripe ones.


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#110 bjkaras

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Posted 27 November 2019 - 12:21 AM

I’ve never seen color in it thought my 10”, but I have seen the central star. It took a long time with high power and averted vision, but there it was. I didn’t even think it was visible through a 10”, but it at 6600 feet in the Sierras. I was camped next to a small lake and the sky was so black and the stars so bright I could see the reflection of the Milky Way off the lake.



#111 Joe Bergeron

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Posted 28 November 2019 - 04:49 PM

I hesitate to say that the characteristic aqua color of planetaries is usually apparent to me in the Ring, even in my 6” scope, though less so than in planetaries with higher surface brightness. It just gets better in bigger scopes. 


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#112 F.Meiresonne

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Posted 28 November 2019 - 05:28 PM

As an imager, I'll note that color you see in images is always strongly enhanced/modified in computer processing.  As it comes straight from the camera, there's little to see, in a number of regards.  _Heavy_ computer processing is as much a part of imaging today as are scopes and cameras.  It's just a different thing than visual observing.

That s strange because in my case on a single shot with a 1200d canon, M57 was very blue , no image processing. The only trouble was it was darn tiny

 

But visual i never saw any color in the ring not even in my 18", nothing. It is just a ring of greyish smoke...

 

See picture ,way too much enlarged, but furhter no processing. It is clearly blue

Attached Thumbnails

  • M57_unprocessed_large.JPG

Edited by F.Meiresonne, 28 November 2019 - 05:33 PM.

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#113 Redbetter

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Posted 28 November 2019 - 11:00 PM

 

See picture ,way too much enlarged, but furhter no processing. It is clearly blue

This shows the wide differences are in color perception.  To me and my family members (not indicating what color I am seeking from them in that image) it is cyan, aquamarine, turquoise or some other variant of bluish-green.  That is how I see it in medium to large scopes as well.  None of us describe it as blue (or as simply green for that matter.)   


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#114 F.Meiresonne

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Posted 29 November 2019 - 09:46 AM

This shows the wide differences are in color perception.  To me and my family members (not indicating what color I am seeking from them in that image) it is cyan, aquamarine, turquoise or some other variant of bluish-green.  That is how I see it in medium to large scopes as well.  None of us describe it as blue (or as simply green for that matter.)   

 

This shows the wide differences are in color perception.  To me and my family members (not indicating what color I am seeking from them in that image) it is cyan, aquamarine, turquoise or some other variant of bluish-green.  That is how I see it in medium to large scopes as well.  None of us describe it as blue (or as simply green for that matter.)   

Language issue we have here. But you are right it more cyan. But in Dutch this something that is not said , turquoise yes ,

But i agree , maybe i should have said cyan...

 

I never buy 'blue' toner for our office printer/copiers...it is cyangrin.gif


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#115 pierce

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Posted 29 November 2019 - 02:31 PM

Language issue we have here. But you are right it more cyan. But in Dutch this something that is not said , turquoise yes ,

But i agree , maybe i should have said cyan...

 

I never buy 'blue' toner for our office printer/copiers...it is cyangrin.gif

actual turquoise can be a wide range of shades from pale blue to quite green, depending on hoiw oxidized it is, so its a poor name for a color.



#116 areyoukiddingme

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Posted 29 November 2019 - 02:47 PM

Read Roger S. Clarke's  Visual astronomy of the deep sky and compare the light levels of Broad Sunlit Day to that of a cloudy night devoid of moon.

 

I can navigate such a night in deep forest. Maybe I can't hunt furry rodents under such low light levels, but I can see as well as our early ancestors did- well enough to flee or to defend themselves against night-hunting predators, as our ancestors must have also done to survive.

 

It's true that scotopic rod vision robs us of color data, but you don't need to see the color of a lion to know it's a big cat.

 

Also, note that, while adding blue to paint to yellow paint does make a green paint; (mixing pigments is "subtractive combinination" by definition) - adding yellow light(green and red cones) to blue light (blue cones) makes white (or a more saturated hue: i.e.  red+blue+green cones) as with the RGB colors of a video display screen(additive combination).  This is the reason we never see green stars- there is always additive combination with a lot of blue and/or red light; usually with a fair to large amount of both: i.e. we see lots of yellow-white /white /blue-white stars.    

 

We can see gas flourescing in a high vacuum in outer space. We can see "dead" Galaxies a billion light years away; So what if we can't see fine detail well enough to read a newspaper or a star-map at light levels less than 1 Quadrillionth of daylight levels? Yes, it's dim!  But, by far the the blackest night sky you'll never see is the blackness behind those bright streetlights in the Walmart Parking lot.  

 

Human eyes are not quite as good as those of night-hunting cats, but our primate ancestors eyes evolved to make effective use of extreme low light levels, and with practice and usage, a dark starry night sky is not a barrier to our dark adapted (eye-brain) sight  the hardware is there, but it must re-learn to interpret those very weak signals..

 

When the power was out here least week, I could see in every room in my home by the light of ONE centrally located candle, with ease.  I actually loved the way things looked in that dim warm darkness. 

There are a range of adaptations in vision that can be separated. For day time, color vision is actually very important for spotting predators. In fact, without color vision, there are animals that you simply will not see (this whole talk is an excellent discussion of how vision works, but the relevant point is here):

 

https://youtu.be/mf5otGNbkuc?t=125

 

As for seeing color in the ring, I find that it is a rather obvious pale blue in my 12.5", but the points about expectations "coloring" my vision are worth exploring.

 

I see the Orion nebula as pale green from my orange zone balcony, and didn't really notice much of the green at all until it was pointed out to me. In the Sierra's, however, it looked almost neon.


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#117 NorthernlatAK

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Posted 03 December 2019 - 12:18 AM

Daytime color vision is/was very important for selecting ripe fruit and very slight differences between poisonous and non-poisonous berries. Turns out women have a more sensitive eyes when it comes to differentiating poisonous berries (gathering) specifically in red colors.

#118 Araguaia

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Posted 03 December 2019 - 07:15 AM

I must have a girl's eyes.  I was just out in a canoe picking berries on the riverbank.  This particular type ripens red - but the difference between very sour and delicious is one day, and a very slight difference in red tonality.  After years of practice, I can make out a ripe one in the shade a bunch of almost-ripes from 30 meters away.  Saves a lot of paddling...

 

While a newcomer to this area would not be able to see the difference, all the old-timers do.  I have no doubt most people are capable of it.




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