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Observing >> Double Star Observing

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caheaton
Carpal Tunnel
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Reged: 05/26/09

Loc: SW Ohio
Zeta Lyrae colors
      #5817096 - 04/23/13 10:02 AM

Hello, stepped out for a bit last night to do some observing (it's been a while as I wimped out for most of this past winter ). Anyway, after observing Saturn for a while I switched over to catch some doubles. After observing the famous double double in Lyra I nudged the scope over and caught Zeta Lyrae, and found it to be a very pretty "yellow and blue pair". After looking at some other people's observations it seems that most people see this pair as both yellow, though to me they were definitely yellow (primary) and light blue (secondary). Equipment at the time was an 80mm F/6 triplet and a 5mm Paradigm ep.

Anybody else see this pair as anything other than yellow?


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GlennLeDrew
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Reged: 06/18/08

Loc: Ottawa, Ontario, Canada
Re: Zeta Lyrae colors new [Re: caheaton]
      #5817676 - 04/23/13 02:33 PM

I've only perceived them as being rather colourless, or 'neutral' white. The B-V index of the primary and secondary are 0.19 and 0.28, respectively. And so the primary has a cooler color cast. If these values are accurate, a yellower *appearing* primary which is really bluer suggests the illusion whereby the brighter object has the warmer hue.

By contrast, note that our yellowish Sun has a definitely 'redder' B-V of 0.656, which we have evolved to consider as white, at least during the day. A B-V of 0.28, not to mention 0.19, is decidedly bluer than sunlight.

Edited by GlennLeDrew (04/23/13 02:44 PM)


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caheaton
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Re: Zeta Lyrae colors new [Re: GlennLeDrew]
      #5817862 - 04/23/13 03:56 PM

Thanks much for the explanation. It seems that when it comes to star colors (especially in doubles) our eyes are not to be trusted!

I found a sketch that is quite close to how the stars appeared to my eyes and seems to show that other have perceived this pair as yellow and bluish.

http://www.perezmedia.net/beltofvenus/archives/images/2006/img2006090402_Zeta...

Real or imagined, the colors of doubles are a relaxing way to pass some time in a light polluted back yard (which a nearly full moon served to only make worse :-) ).


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Rich (RLTYS)Moderator
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Reged: 12/18/04

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Re: Zeta Lyrae colors new [Re: caheaton]
      #5819181 - 04/24/13 05:59 AM

I've also seen both stars as white. I've found you can ask 10 different people the color of a double star and you'll most likely get 10 different answers.

Rich (RLTYS)


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WRAK
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Reged: 02/18/12

Loc: Vienna, Austria, Europe
Re: Zeta Lyrae colors new [Re: Rich (RLTYS)]
      #5821231 - 04/25/13 02:34 AM

For me both light yellow.
In my experience colors of stars show different in different scopes.
Wilfried


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Cepheus Elf
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Reged: 08/01/10

Loc: Rainy, Cloudy Lancashire UK
Re: Zeta Lyrae colors new [Re: caheaton]
      #5821417 - 04/25/13 07:45 AM Attachment (41 downloads)

Here's a photo I took of Zeta Lyrae a little while ago using my DSLR and 6" Newtonian.....see what you think!
It's a color image by the way.

Mick

Edited by Cepheus Elf (04/25/13 07:48 AM)


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GlennLeDrew
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Re: Zeta Lyrae colors new [Re: Cepheus Elf]
      #5823208 - 04/25/13 09:40 PM

It sure looks like the colors are congruent with the B-V indices; slightly bluish primary and slightly yellowish secondary, in relative terms anyway.

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Rich (RLTYS)Moderator
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Reged: 12/18/04

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Re: Zeta Lyrae colors new [Re: GlennLeDrew]
      #5823666 - 04/26/13 06:35 AM

Yes, the brighter star does look bluish.

Rich (RLTYS)


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Bonco
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Reged: 04/17/06

Loc: Florida
Re: Zeta Lyrae colors new [Re: Rich (RLTYS)]
      #5824667 - 04/26/13 03:21 PM

Mick,
Excellent photo with excellent color representation. Thanks for posting. Bill


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caheaton
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Reged: 05/26/09

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Re: Zeta Lyrae colors new [Re: Bonco]
      #5834535 - 05/01/13 02:28 PM

Excellent photo...in my log I'd described it as being an off white primary (it looks cream to me) and a pale yellow secondary.

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MartinTreadgold
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Reged: 04/17/13

Loc: Netherlands
Re: Zeta Lyrae colors new [Re: caheaton]
      #5838453 - 05/03/13 02:01 PM

Try the double star Iota Cancri.. really distict yellow and blue stars

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ziridava
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Reged: 08/17/12

Loc: Arad,Romania,Eastern Europe
Re: Zeta Lyrae colors new [Re: MartinTreadgold]
      #5845977 - 05/07/13 03:47 PM

Last week,using my 76mm F/9 Newtonian at 42x/Zeiss 16.7 Kellner, I saw colors in Zeta Lyrae,about the intensity like in the Perez drawing.
Zeta Lyr is a binocular double star but I don't remember ever to notice colors.Something to check.
Mircea

Edited by ziridava (05/07/13 03:49 PM)


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Bill Boublitz
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Reged: 05/04/13

Re: Zeta Lyrae colors new [Re: ziridava]
      #5846608 - 05/07/13 08:59 PM

Very nice! Great work. Congrats!

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