Discovery of our Galaxy's spiral structure -as it happened

[madbadgalaxyman (Robert)]

Here is an interesting historical document in which the late Donald Osterbrock is interviewed about how the first ever map was made of our own Galaxy's spiral structure:
http://www.aip.org/history/ohilist/4809.html#1

In the early 50s, Osterbrock and Morgan and Sharpless made the first map of the spiral structure in our part of the Milky Way.

Here is the Morgan-Osterbrock-Sharpless diagram of the local spiral arms of our own Galaxy, as updated by Bart Bok in his book "The Milky Way" : :


Sharpless is also famous for an important catalog of nebulae:
http://www.iceinspace.com.au/forum/s...d.php?t=118987

Note added in edit:
The astronomical publication record of Stewart Lane Sharpless seems to have ended in the mid 1980s when he was around 60, unless he continued to get published in very obscure journals. His last research grants from the University of Rochester also were in the mid 1980s
Perhaps this is why he is very poorly remembered compared to co-authors Donald Osterbrock and W.W. Morgan, who were high-profile astronomers that were generally acknowledged as amongst the most eminent of their generation.

[madbadgalaxyman (Robert)]

Further to my previous post, here is a remarkable biography of W.W. Morgan, the co-creator of the modern system of spectral classification of stars, and the discoverer (or co-discoverer) of the spiral structure of our own galaxy. It is remarkably interesting to contemplate that there was a time - not so long ago - when it had just been proved that the Milky Way is just one galaxy of many, yet nobody actually knew what type of galaxy the Milky Way is!

http://arxiv.org/ftp/arxiv/papers/1112/1112.0243.pdf

madbadgalaxyman's comment:
It is important when reading the results of research into the history of science to remember that the conclusions of these "first or early or initial researches" into astronomical history are often quite inaccurate, and that later historical research often revises the earlier conclusions. For instance I initiated a thread on whether or not Hubble actually discovered the expansion of the universe, and it turned out that the much admired and very famous Hubble discovered a lot less than he is usually credited with.

[madbadgalaxyman (Robert)]

My point about the writing (and the later rewriting) of scientific history, and about the correct - or incorrect - assignment of the credit for a discovery to a particular person, is relevant when we try to assess the truth or partial-truth of the biography of W.W.Morgan by William Sheehan. When it comes to discussing who discovered and first mapped the spiral arms near the Sun, Sheehan's view is that the credit is all to "Morgan!...Morgan!...Morgan!"

Given the powerful and colourful prose of Sheehan, and the fact that science writers like to plant in the reader's mind the very powerful myth of the "lone genius who sees so much further than others", most readers of this biography of Morgan will probably conclude: "It must have been thus!"

But I hasten to point out that while W.W. Morgan was undoubtedly one of the very most important astronomers of his generation, the short note in the Astronomical Journal that announced the discovery of our Galaxy's local Spiral Structure is by W.W. Morgan and Stewart Sharpless and Donald Osterbrock:
http://adsabs.harvard.edu/abs/1952AJ.....57....3M

Given that the scientific contributions of Stewart Sharpless have largely been forgotten, with the exception of his Very Important catalog of bright nebulae, I think it would be important to accurately assess whether or not he had only a small part in the discovery;
really, it is not fair of Sheehan to assign credit to only one of the three authors of the paper.

I think it is significant that Bart Bok, who was also active in the early 1950s in the elucidation of the structure of our own Galaxy, refers (in the fifth edition of "The Milky Way") to the fundamental diagram of the nearby spiral arms as
The Morgan-Osterbrock-Sharpless diagram


[[ Don't forget that in those days, senior astronomers found it easy to hog the credit that belonged in part to their junior co-researchers.
Hubble himself was one of the greatest offenders in this regard, especially in his very shabby treatment of Humason! (and also of Georges Lemaitre) ]]

[madbadgalaxyman (Robert)]

Ken Croswell, in his somewhat misleadingly titled 1995 book "The Alchemy of The Heavens" , states that Stewart Sharpless has (and here I directly quote Croswell) "left the profession".

For those of you familiar with the typical late-career or post-career activities of professional astronomers, this can be viewed as a very unusual thing to do;
because a lot of retired or semi-retired professional astronomers still continue to engage in at least some astronomical activities, usually one or more or the following:
- teaching astronomy
- writing the occasional paper
- writing popularizations of astronomy
- writing histories of astronomy and writing down reminiscences of their careers
- working on atlases and catalogs and data compilations and on books surveying their field of specialization.
- keeping up with their field, and attending conferences

Ken Croswell, and also Owen Gingerich in his 1985 historical paper 'The Discovery of The Spiral Arms of the Milky Way' (( http://adsabs.harvard.edu/abs/1985IAUS..106...59G ) , assign substantial credit to W.W. Morgan and to Donald Osterbrock and to Stewart Sharpless for the discovery of the local Spiral Structure of the Milky Way Galaxy. It is, however, likely that Morgan was the driving force behind this work on elucidating the spiral arms near the Sun, as he had been working this problem for years beforehand, together with another very competent (but little remembered) astronomer called Jason J. Nassau. The work, in particular, required the use of a lot of Morgan's exceptional knowledge about spectral classification and the luminosities of stars, in order to figure out the distances of OB stars in the spiral arms.

Donald Osterbrock is on record as stating that he and Sharpless got more credit than they deserved for this work, but this reminiscence by Osterbrock doesn't mean that his judgment on this matter is a historical fact. Perhaps Osterbrock is right, but this assessment needs to be evaluated, and historians should also pay more attention to the role of J.J. Nassau.

There is always an element in history writing of "telling ourselves great old stories about the past", and this is also very true of astronomical history writing;
so it is important to view any gripping and powerful story about the past with a critical eye.

[Tinderboxsky (Steve)]

An interesting and informative read Robert. I am enjoying your commentary and observations.
Cheers

Steve