[AZ-Observing] Re: History in My Hands

>>  Vesto M. Slipher...
>>  was the first person to make spectrographic observations of galaxies...

     Their spectra were of course photographed much earlier by Huggins,
Scheiner, and others.  Slipher's observations were the first to yield
reliable radial velocities.

>>  ...Arguably, the most significant
>>  observation he  made in this field was that of December 30, 1912,
>>  to January 1, 1913.

     This was last of four similar plates of M31, the first being in        
September 1912.  These are detailed in the relevant Lowell Bulletin (no 58),
published in 1913.

>>  ...and how long it
>>  had taken  before he came to the conclusion that such incredible rates of
>>  motion could only  be explained if the objects were far beyond
>>  our home galaxy?

     I don't know that we have any evidence that he ever thought this
until Hubble matched his distance estimates with Slipher's velocities
to produce what's now called the 'Hubble law'.  I doubt very many people
could wrap their minds around the notion of an expanding universe until
after 1929, when Hubble published the distance/velocity relation.

     Bill Hoyt published a sketch scientific biography of Slipher in 1980,
but alas didn't live to produce the book-length bio he planned.  Next
time you're up here (Bill F), I think we can dig out a copy of Hoyt's
article for you, which has many interesting details, and a huge bibliography
(a 23-page article with _140_ footnotes!).
     I might mention that part of the regular Lowell includes the exhibit
that contains Slipher's spectrograph and camera, and the Sep 1912 spectrum.

\Brian
--
See message header for info on list archives or unsubscribing, and please 
send personal replies to the author, not the list.

Other related posts: