Re: [ISTATALK-L] Rainbow Question

[Jim Kaler <kaler@xxxxxxxxxxxxxx>]

Hi -- Let me kick in on this.  The eye can discriminate a few hundred
colors, so one has many choices.  The "seven" colors probably come
from the "magic" of 7 from ancient times, most likely from the seven
moving bodies of the sky, sun, moon and five ancient planets, which we
see in the 7 days of th week.  The
principal colors are red orange yellow green blue violet; indigo
makes an unnecessary 7th, which is really blue-violet.  We see the same
thing in the Seven Sisters (Pleiades) star cluster, wherein most
eyes just see 6. Etc.  No reaon NOT to pick indigo, but
when the students
hit college astro or physics it is never used, as it is really not needed.

Jim Kaler

****************************************************************
Jim Kaler
Professor Emeritus of Astronomy   Phone: (217) 333-9382
University of Illinois            Fax: (217) 244-7638
Department of Astronomy           email: kaler@xxxxxxxxxxxxxx
103 Astronomy Bldg.               web: http://www.astro.uiuc.edu/~kaler/
1002 West Green St.
Urbana, IL 61801
USA

Visit: http://www.astro.uiuc.edu/~kaler/ for links to:
  Skylights (Weekly Sky News updated each Friday)
    Stars (Portraits of Stars and the Constellations)
      The StarGazer (a new planetarium show)
*****************************************************************




On Fri, 17 Dec 2004, Judith A. McKee wrote:

> I read on the internet that indigo is no longer considered a color in the
> rainbow and has been removed from some texts.  Is this true?  What does anyone
> know about the matter?  Alas!  It leaves ROY G BIV with a last name that has no
> vowel!
>
> Judy McKee
> Scientist in Residence
> Wilmette Public Schools
>
> ***********************************************************
> For problems with ISTATALK-L, please contact
> listadmn@xxxxxxxxxxxxxxxxxxxxxxxxxxxx for assistance.
>
> To unsubscribe, send a message to listadmn@xxxxxxxxxxxxxxxxxxxxxxxxxxxx
> that states, "Please unsubscribe me from the ISTATALK-L listserv."
> ************************************************************

***********************************************************
For problems with ISTATALK-L, please contact
listadmn@xxxxxxxxxxxxxxxxxxxxxxxxxxxx for assistance.

To unsubscribe, send a message to listadmn@xxxxxxxxxxxxxxxxxxxxxxxxxxxx
that states, "Please unsubscribe me from the ISTATALK-L listserv."
************************************************************