Harvard Astronomy 201b

Archive for January, 2011|Monthly archive page

ARTICLE: On the Dark Markings in the Sky

In Journal Club, Journal Club 2011 on January 30, 2011 at 4:55 pm

Read the paper by E.E. Barnard (1919)

Summary by Bence Beky


It would be unwise to assume that all the dark places shown on photographs of the sky are due to intervening opaque masses between us and the stars. In a considerable number of cases no other explanation seems possible, but some of them are doubtless only vacancies. I do not think it necessary to urge the fact that there are obscuring masses of matter in space. This has been quite definitely proved in my former papers on this subject. If any doubt remains of this it will perhaps be readily dispelled by a close examination of the photographs previously printed.

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Positions of Barnard’s Nebulae

In Uncategorized on January 28, 2011 at 3:37 pm

This map shows the locations of Barnard’s objects (red circles) on top of the SFD dust map. The size of the circle is proportional to the size of the nebula as reported in Barnard’s catalog.

Y2K Sample Postings

In Uncategorized on January 25, 2011 at 4:58 am

Scott Schnee’s Page on Bohlin, Savage & Drake 1978 A Survey of Interstellar H I From Lyman Alpha Absorption Measurements II R. C. Bohlin, B. D. Savage, and J. F. Drake The Astrophysical Journal , 224:132-142, 1978 August 15

HTML Page By “Jonathan” (on:  1)  “Evidence for Magnetic and Virial Equilibrium in Molecular Clouds.”  Myers, P. C.; Goodman, A. A.  (ADS) Paper I.  and  2)  “Magnetic Molecular Clouds: Indirect Evidence for Magnetic Support and Ambipolar Diffusion.”   Myers, P. C.; Goodman, A. A.  (ADS)  Paper II.)

“Fancy” Site on “The Correlation between Gas and Dust in Molecular Clouds: L977” (Alves, Lada & Lada)

Shells & Supershells Page “H I shells and supershells.”  Heiles, C. Astrophysical Journal, Part 1, vol. 229, Apr. 15, 1979, p. 533-537, 539-544. Full text here.

“Dark Markings in the Sky” (E.E. Barnard Extinction “History” & More)

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In Uncategorized on January 24, 2011 at 6:52 pm
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Sample Post: Definitions of Temperature

In Uncategorized on January 22, 2011 at 4:03 am

A list of the more common uses of the term “temperature”, and their interrelationships

The Radex manual gives a nice, concise description of these terms

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