Jump to content


Photo

Zeta Lyrae colors

  • Please log in to reply
12 replies to this topic

#1 caheaton

caheaton

    Surveyor 1

  • *****
  • Posts: 1573
  • Joined: 26 May 2009
  • Loc: SW Ohio

Posted 23 April 2013 - 09:02 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 :p ). 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?

#2 GlennLeDrew

GlennLeDrew

    Voyager 1

  • *****
  • Posts: 10710
  • Joined: 17 Jun 2008
  • Loc: Ottawa, Ontario, Canada

Posted 23 April 2013 - 01:33 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.

#3 caheaton

caheaton

    Surveyor 1

  • *****
  • Posts: 1573
  • Joined: 26 May 2009
  • Loc: SW Ohio

Posted 23 April 2013 - 02:56 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.perezmedi...6090402_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 :-) ).

#4 Rich (RLTYS)

Rich (RLTYS)

    Fly Me to the Moon

  • *****
  • Moderators
  • Posts: 5179
  • Joined: 18 Dec 2004
  • Loc: New York (Long Island)

Posted 24 April 2013 - 04:59 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)

#5 WRAK

WRAK

    Apollo

  • -----
  • Posts: 1154
  • Joined: 18 Feb 2012
  • Loc: Vienna, Austria, Europe

Posted 25 April 2013 - 01:34 AM

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

#6 Cepheus Elf

Cepheus Elf

    Explorer 1

  • -----
  • Posts: 94
  • Joined: 01 Aug 2010
  • Loc: Rainy, Cloudy Lancashire UK

Posted 25 April 2013 - 06:45 AM

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

Attached Files



#7 GlennLeDrew

GlennLeDrew

    Voyager 1

  • *****
  • Posts: 10710
  • Joined: 17 Jun 2008
  • Loc: Ottawa, Ontario, Canada

Posted 25 April 2013 - 08:40 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.

#8 Rich (RLTYS)

Rich (RLTYS)

    Fly Me to the Moon

  • *****
  • Moderators
  • Posts: 5179
  • Joined: 18 Dec 2004
  • Loc: New York (Long Island)

Posted 26 April 2013 - 05:35 AM

Yes, the brighter star does look bluish.

Rich (RLTYS)

#9 Bonco

Bonco

    Gemini

  • *****
  • Posts: 3444
  • Joined: 17 Apr 2006
  • Loc: Florida

Posted 26 April 2013 - 02:21 PM

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

#10 caheaton

caheaton

    Surveyor 1

  • *****
  • Posts: 1573
  • Joined: 26 May 2009
  • Loc: SW Ohio

Posted 01 May 2013 - 01:28 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.

#11 MartinTreadgold

MartinTreadgold

    Vostok 1

  • -----
  • Posts: 110
  • Joined: 17 Apr 2013
  • Loc: Netherlands

Posted 03 May 2013 - 01:01 PM

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

#12 ziridava

ziridava

    Vostok 1

  • -----
  • Posts: 123
  • Joined: 17 Aug 2012
  • Loc: Arad,Romania,Eastern Europe

Posted 07 May 2013 - 02:47 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

#13 Bill Boublitz

Bill Boublitz

    Vostok 1

  • -----
  • Posts: 127
  • Joined: 04 May 2013

Posted 07 May 2013 - 07:59 PM

Very nice! Great work. Congrats!






Cloudy Nights LLC
Cloudy Nights Sponsor: Astronomics