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59 Ser, a Green star?

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#1 stevecoe

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Posted 01 June 2006 - 04:04 AM

OK, I know that green stars are supposed to be impossible using just the temperature charts and other stellar physics.

However, I am out in my backyard tonight doing multiple stars in Serpens and number 59 on the Flamsteed list is pretty obviously green to my eye. It is located at 18 27.2 and +00.2. This binary consists of a 5.3 and 7.6 mag pair, sep 3.8 arcsec at a PA of 318 degrees.

In my 8 inch SCT it is just split at 133X and shows better separation at 167X. The pair has good color contrast at both powers. I see the colors as light yellow and medium green or aqua at both magnifications.

So, put 59 Ser on your observing list and see if you agree;
Steve Coe

#2 Acheron

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Posted 01 June 2006 - 04:17 AM

I will try ASAP

#3 SabiaJD

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Posted 01 June 2006 - 09:34 AM

My observing notes from July 2004 and Aug 2005 show that I recorded a Yellow primary and pale blue seconday.
TV 101 at 162X.
I'll have to revisted this one with a other scopes to discover if there is any greenish to the secondary.

#4 asteroid7

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Posted 01 June 2006 - 09:57 AM

Herschel, the famous astronomer, called this pair: orange and green.

#5 photonovore

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Posted 01 June 2006 - 11:06 AM

Green stars are certainly possible if defined as those emitting most strongly at ~530nm ( which equates top about a ~10,000K star). They simply *appear* white to our eyes. Exceptions are doubles with reddish primaries and fainter ~10,000K secondaries the latter which can appear greenish to some people due to the effects of intensified contrast upon color perception in the eye. 59 Serpentis B is a type A0 star which puts it in this range of temperature. Beta Librae is a *single* star that many have noted as greenish; it's temp is ~12,000K.

Steve, i notice you have 59 Seprentis listed in a SAC article on Serpens you wrote as white/lt. blue (as observed with a 13" reflector). What do you suppose caused the apparant color difference when viewed this time with the 8"?

#6 stevecoe

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Posted 01 June 2006 - 01:34 PM

Mardi;

I just noticed the difference in the color given in my two observations. The old observation with my 13 inch Newt was from out of town on a much darker night, the most recent from the backyard inside the light dome of Phoenix. So, I would certainly been more dark adapted at the earlier observation. I don't know if the difference in 8 and 13 inches of aperture would make a big difference. One more, I am now 57 years old and the old observation is from about 12 years ago. Maybe just the combination of all three of those effects.

Give it a try;
Steve Coe

#7 LivingNDixie

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Posted 01 June 2006 - 03:27 PM

Aperture effect the way colors of stars appear, as does sky conditions. I would think a non dark adapted eye would pick up more color in stars then a dark adapted one.

#8 SaberScorpX

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Posted 01 June 2006 - 03:53 PM

From http://www.faqs.org/.../section-7.html :

"The colors we see depend not only of the wavelength mix the eye receives at a particular spot, but also on a number of other factors.
For instance the brightness of the light received, the brightness and wavelength mix received simultaneously in other parts of the field of view (sometimes visible as 'contrast effects'), and also the brightness/wavelength mix that the eye has previously received (sometimes visible as after-images).
One isolated star, viewed by an eye not subjected to other strong lights just before, and with very little other light sources in the field of view, will virtually never look green. But put the same star close to another, say, reddish star, and that same star may immediately look greenish, due to contrast effects (the eye tries to make the 'average' color of the two stars appear white)".



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#9 stevecoe

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Posted 01 June 2006 - 05:01 PM

Saber;

I have never known that the mental process going on was to average the colors of the two stars to get a white balance. Ain't that weird?

Steve Coe

#10 SaberScorpX

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Posted 02 June 2006 - 03:10 AM

Agreed, Steve.

Weird and fascinating.
That the eye-brain combination makes these interpretations without skipping a beat is a remarkable process.
I can spend hours at those optical illusion websites.



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#11 Mark K

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Posted 02 June 2006 - 04:06 AM

If you want a real colour test, try 95 Herculis.

This duo has been described as
"lemon"/"white" and "cherry-red/apple-green", among others.

There is a thread from last year about it :

#12 Mark K

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Posted 06 June 2006 - 04:01 AM

Aperture effect the way colors of stars appear, as does sky conditions. I would think a non dark adapted eye would pick up more color in stars then a dark adapted one.


I have noticed it with Gamma Leo last week. Against a dark sky in March, the stars were both gold with little colour difference between them. Against a twilight sky, with Gamma barely visible with the naked eye, I noticed a subtle but distinct difference beteen the two; the primary was slightly more orange and the secondary had a hint of lime.

#13 stevecoe

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Posted 06 June 2006 - 04:34 AM

Mark;

That is certainly unusual, I will try it next week.

Steve

#14 David Knisely

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Posted 06 June 2006 - 11:43 PM

OK, I know that green stars are supposed to be impossible using just the temperature charts and other stellar physics.

However, I am out in my backyard tonight doing multiple stars in Serpens and number 59 on the Flamsteed list is pretty obviously green to my eye. It is located at 18 27.2 and +00.2. This binary consists of a 5.3 and 7.6 mag pair, sep 3.8 arcsec at a PA of 318 degrees.

In my 8 inch SCT it is just split at 133X and shows better separation at 167X. The pair has good color contrast at both powers. I see the colors as light yellow and medium green or aqua at both magnifications.

So, put 59 Ser on your observing list and see if you agree;
Steve Coe


Well, in the NexStar 9.25 SCT, I saw the primary as a yellowish-white and the companion as white with just a hint of a bluish tint, although it is doesn't show a lot of color (its similar to the color of the companion to Ras Algethi or Gamma Delphini). I noted no hint of any greenish hint, but then again, I have never really seen a true "greenish" companion to any star. Clear skies to you.

#15 Acheron

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Posted 08 June 2006 - 08:19 AM

8" scope Newton, 200x, average seeing, Moon in the sky, LM was 5.20

59 Ser

Primary is yellow but secondary is something between orange and green!!!
How is this possible?

#16 Jim Nelson

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Posted 08 June 2006 - 08:06 PM

"Color" is not really a property of external objects, or wavelengths of light. "Color" is created in the brain.

While we speak of wavelengths of light as corresponding to colors, this is an oversimplification. The very same wavelengths can appear completely different colors under different circumstances; and inversely, different wavelengths of light can appear to be the same color.

We generally only see color during the daytime, where we see fairly evenly illuminated scenes. Under these circumstances, our perception of color is pretty consistent. Normally, we don't notice any strange color effects, except under unusual conditions.

And double stars certainly count as unusual conditions! It's nighttime, most of the visual scene is dark; the stars are emitting light, not reflecting it; they're point sources, not areas. It really plays heck with our poor visual system!

#17 SaberScorpX

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Posted 09 June 2006 - 02:36 AM

I'd like to think of it as healthy exercise.
Keep those rods, cones, and neurons on their, uh, toes.



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#18 novbabies

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Posted 09 June 2006 - 04:05 AM

I have always seen gamma Andromedae as orange and green.

Anyone else remember that people used to say that either Zubenelgenubi or Zubenelschemali (pardon the spelling, and I don't actually remember which) was a green star?

#19 Mark K

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Posted 09 June 2006 - 04:33 AM

I have always seen gamma Andromedae as orange and green.

Anyone else remember that people used to say that either Zubenelgenubi or Zubenelschemali (pardon the spelling, and I don't actually remember which) was a green star?


It's Beta Librae that is said to be the only green naked-eye star, but I have only ever seen it as white, with or without optical aid.

Incidentally, the awe-inspiring names of the chief stars in Libra are a throwback to the old Arabic designation of the group as forming part of Scorpius.

Alpha (Zubenelgenubi) means "The Southern Claw" and
Beta (Zubenelschemali) means "The Northern Claw".

It was only during the age of Julius Caesar when astronomers recognised Libra as a separate group, and amputated Scorpius.

#20 novbabies

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Posted 09 June 2006 - 04:51 AM

I have always seen gamma Andromedae as orange and green.

Anyone else remember that people used to say that either Zubenelgenubi or Zubenelschemali (pardon the spelling, and I don't actually remember which) was a green star?


It's Beta Librae that is said to be the only green naked-eye star, but I have only ever seen it as white, with or without optical aid.

Incidentally, the awe-inspiring names of the chief stars in Libra are a throwback to the old Arabic designation of the group as forming part of Scorpius.

Alpha (Zubenelgenubi) means "The Southern Claw" and
Beta (Zubenelschemali) means "The Northern Claw".

It was only during the age of Julius Caesar when astronomers recognised Libra as a separate group, and amputated Scorpius.


Thanks Mark!

#21 stevecoe

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Posted 12 June 2006 - 07:00 PM

So, these are obviously the stars we need to tell people about when they ask for star names for their children...

Do you know anyone nicknamed "Zuben"?
Steve Coe

#22 David Knisely

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Posted 13 June 2006 - 12:07 AM

So, these are obviously the stars we need to tell people about when they ask for star names for their children...

Do you know anyone nicknamed "Zuben"?
Steve Coe


Nope, but I recall at one Astronomical League National Convention where the "Star Bowl" was held (a "college bowl" knowledge competition). One of the team names was "The Zubenelgenubians". Clear skies to you.

#23 SaberScorpX

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Posted 13 June 2006 - 01:34 AM

re: Do you know anyone nicknamed "Zuben"?

They probably all just go by 'Ben'.
Look for one green eye.



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#24 novbabies

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Posted 13 June 2006 - 05:18 AM

So, these are obviously the stars we need to tell people about when they ask for star names for their children...

Do you know anyone nicknamed "Zuben"?
Steve Coe


Just Zuben Mehta the conductor...

#25 Carol L

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Posted 13 June 2006 - 11:57 PM

Steve, thanks for the heads-up on 59 Serpentis. The most recent green-ish star I've seen is Mu 1 Boo. The A star was logged in as being 'golden topaz with a strong hint of lime' and the B star was 'smokey lavender'. The scope was an Orion 80ST at 30x (no CA filter was used).

The only time I saw a brilliant green star was over three years ago on January 3rd 2003. I was out with the LX-10 looking at doubles in Monoceros and the next one on the list was Struve 1052, located inside of open cluster NGC 2353. Also inside the open cluster was HR2739, casting off the most beautiful shade of emerald green this side of Oz! Almost an hour was spent fiddling with ep's and Barlows, but no matter what combination was used, the star remained green which meant it wasn't an optics fluke.

Sadly, that was the only time HR2739 looked green. I checked it a few more times that week and have been checking it ever since, but all I get is a yellow-white. No idea what caused the color, either. It's not a double star, so there wasn't a companion making my brain create contrast effects. And I always use a white light when working with doubles because light activates the color-receptors in our eyes (Stephen, I'm picturing little cones lifting teeny barbells :lol:).
So as far as I can tell, it wasn't anything I did... maybe there was something in the atmosphere that night, who knows. Whatever it was though, I sure wish it'd happen again.


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