[AZ-Observing] Re: Mizar as spectroscopic binary

Alcor and Mizar are one of my favorite objects, too. A quick review on 
my bookshelf turned up the article in Burnham’s Celestial Handbook – 
Vol. 3, pp. 1953-1955.
Mizar is known for many “firsts” –
- First double star discovered – by Riccioli (1650)
- First double star to be photographed – by G.P. Bond at Harvard (1857)
- First binary to be detected spectoscopically (the primary star, Mizar 
A) – Pickering, again at Harvard (1889)
- Mizar B radial velocity shifts detected as early as 1908 by E.B. Frost
- Astrometric measurements have detected a third component (also a 
variable star)
A quote by C.F. Barns (1001 Celestial Wonders): “Pioneer star ... [with 
Alcor] The pair, so happily placed in the crook of the Big Dipper's 
handle, never fail to inspire awe, however frequently observed.”
My curiosity was piqued by the question re: what aperture, etc. would be 
needed to "resolve" the spectroscopic binary components of Mizar... Here 
are the best sources I quickly located (on the web)...
(1) Dr. James B. Kaler, author of several highly interesting books on 
stars has written this short article:
http://www.astro.uiuc.edu/~kaler/sow/mizar.html
(2) But the best review (so far) about Mizar, throughly covering its 
rich history and concluding with an excellent review of the latest 
research, being conducted at Lowell Observatory out at Anderson Mesa 
with the Navy Prototype Optical Interferometer, is this 1999 article by 
Leos Andros, "A New View of Mizar":
http://www.leosondra.cz/en/mizar/
The NPOI consists of an array of several 35cm (13.75 inch) mirrors, 
separated by a maximum of 38 meters (125 feet).

So the answer is, a BIG, LONG interferometer (not a spectroscope). 
Seriously, I doubt anybody will ever actually "view" the separated 
components of Mizar, as they are separated by only about 7 to 8 
 >thousandths< of an arc-second.... Perhaps when the >next< generation 
of truly HUGE telescopes gets built....

Finally, for an exhaustive (86 pages!) professional review of the 
state-of-the-art of astronomical interferometry, have a crack at this 
2003 article by John D. Monnier, “Optical Interferometry in Astronomy”...
http://fr.arxiv.org/PS_cache/astro-ph/pdf/0307/0307036v1.pdf

Have Fun!!
Gene Lucas
(17250)

Dan Heim wrote:

>Jeff,
>DFAC was doing an Astronomy Night for the Boulder Creek High School
>Astronomy Club, Saturday night up here at Heimhenge.  I too was surprised by
>the reactions to Mizar A/B, which seemed to be one of their favorite
>objects.  Of course, there were the usual "ooo's" and "ahh's" over Saturn
>and the Moon, but they really seemed to like the double star thing ...
>perhaps because most had never before encountered the concept of a double
>star.  I don't know.  When I explained about each of the stars being
>themselves double (albeit spectroscopic) that wowed them even further.
>Several asked "How big a scope would you need to see the double double?"  I
>had no idea, so I just said special instruments were needed, i.e., a
>spectroscope, and that they couldn't be split with just a telescope.  Did I
>lie?  Couldn't find the answer on the web when I searched later.
>Dan Heim
>President, Desert Foothills Astronomy Club http://www.dfacaz.org
>  
>

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