The Method of "COLOR-DIFFERENCE."

Becker, W.

doi:10.1086/145011

Cited by 7 publications

(2 citation statements)

References 0 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The X -1 extinction law was firmly established over the wavelength range from X ~ 3500 Â to ~ 6000 Â. The small departures from it, imitating X"° 6 over part of the range were found from this work (Greenstein 1946) using the color difference method, independently invented by Becker (1948). Whitford (1943, 1945) extended the wavelength range redward to 10,000 A. Whitford (1948) reached 2 \x.…”

Section: B the Wavelength Dependencesupporting

confidence: 54%

“…Large values of R were initially claimed using this method. Walker (1962), Becker (1966), andGarrison (1970) showed that the method is subject to large systematic errors and that the evidence favors AJE(R -V) ~ 3 and A B IE(R -V) ~ 4 most places in the solar neighborhood. Exceptions are, however, welf established such as the anomaly in the Orion Trapesium (0 Orionis), but these are rare.…”

Section: B the Wavelength Dependencementioning

confidence: 99%

See 1 more Smart Citation

Comment on the 1930 Trumpler Paper on Interstellar Extinction

Sandage¹

1988

PASP

View full text Add to dashboard Cite

The influence of this second Trumpler paper on subsequent astronomical development has been even greater than his 1925 evolution paper. The work sets out the first convincing demonstration of the presence of general interstellar extinction with a method that is direct and compelling. The argument was so convincing that it is generally credited with changing the prevailing opinion about the existence of general absorption, in contrast to the dark patches seen by Herschel, and photographed by Wolf, by Barnard (1913Barnard ( , 1919Barnard ( , 1927, and others. The patches are due to discrete clouds. The general absorption is due to a more diffusely spread medium.The paper is a lesson in exposition. One subject naturally flows into another. In 13 Journal pages, ten subjects are discussed, each of which has developed into separate central disciplines concerning interstellar dust.After an introductory paragraph which arrives directly at the point, Trumpler reviews the three types of absorption. Here he anticipates many of the methods that have subsequently been used for modern measurements. He describes general absorption and contrasts it with the "monochromatic" absorption of the stationary interstellar spectral lines first found by Hartman (1904) in the spectra of spectroscopic binaries. He then discusses the previous evidence for general absorption. The physical process of dispersion of the velocity of light (finally shown by Kienle in 1923 not to exist in connection with interstellar extinction) is dismissed as not being effective in the space between the stars.General star counts by Halm and by Schalen (references by Trumpler) are shown to be quite suggestive that extinction, increasing with distance, exists. However, this evidence is not decisive because interpretation of the star-count data rests on assumptions (generally unproved at the time) as to the true spatial distribution of the stars. Depending on the assumptions, the analysis yields a variety of answers.Trumpler then introduces his cluster method. Here *One in a series of invited reviews celebrating the eentenary of the Astronomical Society of the Pacific.

show abstract

Section: B the Wavelength Dependencesupporting

confidence: 54%

Section: B the Wavelength Dependencementioning

confidence: 99%