Concepedia

P. D. Usher

PD

Statistics

Publications

13

Citations

280

H-Index

11

Active since

1966

Affiliations

Pennsylvania State University(Current)

Goddard Space Flight Center

University of Pennsylvania

P. D. Usher is an author at Pennsylvania State University specializing in physics, natural sciences, and astronomy.

ORCID

Publications per year

1966–1990

13

Publications

13

On the Optical Search for the X-Ray Sources CYG X-1 and CYG X-2

R. Giacconi, P. Gorenstein, H. Gursky et al. · The Astrophysical Journal · 1967 · 48 citations

, , +17

A medium-bright quasar sample - New quasar surface densities in the magnitude range from 16.4 to 17.65 for B

K. J. Mitchell, III Warnock A., P. D. Usher · The Astrophysical Journal · 1984 · 41 citations

, , +15

On the light variations of Seyfert galaxy 3C120

Igor Jurkevich, P. D. Usher, B. S. P. Shen · Astrophysics and Space Science · 1971 · 29 citations

, , +11

The Generalized Riccati Transformation as a Simple Alternative to Invariant Imbedding

G. B. Rybicki, P. D. Usher · The Astrophysical Journal · 1966 · 27 citations

, , +10

Faint blue objects at high galactic latitude. I - Palomar Schmidt field centered on selected area 57

P. D. Usher · The Astrophysical Journal Supplement Series · 1981 · 27 citations · Full text

, , +9

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