scholarly journals Photoelectric Measurements of Extragalactic Nebulae.

1954 ◽  
Vol 120 ◽  
pp. 439 ◽  
Author(s):  
C. J. van Houten ◽  
J. H. Oort ◽  
W. A. Hiltner
Keyword(s):  
Photoelectric Measurements

scholarly journals Asteroid Polarimetry: A Progress Report

1971 ◽  
Vol 12 ◽  
pp. 91-94
Author(s):  
J. Veverka
Keyword(s):  
Present Status ◽  
Progress Report ◽  
Polarization Curves ◽  
Photographic Method ◽  
Polarization Measurements ◽  
Partial Data ◽  
Low Sensitivity ◽  
Photoelectric Measurements

This is a brief report on the present status of asteroid polarimetry. A detailed paper is in preparation jointly with T. Gehrels.The first polarization measurements of asteroids were made by Lyot (1934), who photographically determined the polarization curves of Ceres and Vesta. These curves are reproduced by Dollfus (1961). Unfortunately, because of the low sensitivity of the photographic method, they do not agree very well with recent photoelectric measurements.The first photoelectric polarization measurements of asteroids were made by Provin (1955) (details of this work are given by Dollfus, 1961), and in recent years this work has been extended by Gehrels (unpublished) and by Veverka (1970). To date, fairly complete polarization curves for about a dozen asteroids have been obtained, and at least partial data are available for twice that number.

scholarly journals Photometric Axis Measurements of the Zodiacal Light at Large Elongations

1980 ◽  
Vol 90 ◽  
pp. 45-48
Author(s):  
H. Tanabe ◽  
A. Takechi ◽  
A. Miyashita
Keyword(s):  
Spatial Distribution ◽  
Interplanetary Dust ◽  
The Sun ◽  
Zodiacal Light ◽  
The Earth ◽  
Photoelectric Measurements ◽  
Ecliptic Longitude

Measurement of the position of the photometric axis of the zodiacal light at large elongations (90 ° < λ − λ⊙ < 270°; λ:ecliptic longitude, λ⊙: ecliptic longitude of the sun) provides information about the spatial distribution of the interplanetary dust outside the orbit of the Earth. However, modern photoelectric measurements in this part are scarce, except for the Gegenschein region, because of the observational difficulty due to faintness of this part of the zodiacal light.

scholarly journals The Nature of Balmer Line Variability in Chemically Peculiar Stars

1986 ◽  
Vol 90 ◽  
pp. 179-180 ◽  
Author(s):  
B. Musielok
Keyword(s):  
Wavelength Region ◽  
Model Atmosphere ◽  
Balmer Line ◽  
Peculiar Stars ◽  
Metal Abundance ◽  
Balmer Lines ◽  
Higher Temperature ◽  
Chemically Peculiar Stars ◽  
Photoelectric Measurements ◽  
Ap Stars

Photoelectric measurements of the β-index were made for six Ap-stars (56 Ari, 41 Tau, φ Dra, HD 188041, HD 215441, HD 221568) and one He-rich star (HD 184927). For all these stars the minimum of β occurs at a phase of maximum light at a wavelength longward of the null-wavelength region. Such coincidence can be explained by the blanketing mechanism proposed by Kodaira (1973) for the explanation of the Hγ line variations in HD 221568. According to Kurucz (1979), for stars hotter than 9000K an increase of metal abundance in the atmosphere causes an increase of the visible flux and an simultanous decrease of equivalent widths of Balmer lines. The same changes of the visible flux and equivalent widths of Balmer lines can be obtained using a model atmosphere with a suitable higher temperature. Using the Kurucz (1979) model atmospheres, temperature differences were calculated, which are necessary to obtain the observed decrease of the (β-index and the increase of the flux in a given photometric band.

scholarly journals PHOTOELECTRIC MEASUREMENTS OF MEMBRANES

1990 ◽  
Vol 51 (6) ◽  
pp. 793-818 ◽  
Author(s):  
HANS-WILHELM TRISSL
Keyword(s):  
Photoelectric Measurements
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