Absolute photometry of the light of the night sky ; the zenith intensity of Haleakala (latitude N 20.7 degrees) and at Fritz Peak (latitude N 39.9 degrees) /

Includes bibliography.

Practical photometry: a guide to the study of the measurement of light.

At head of title: London County Council.

Precision measurement and calibration: selected NBS Papers on radiometry and photometry/

Mode of access: Internet.

The complex broad-band X-ray spectra of Seyfert galaxies /

Cover: Laboratory for High Energy Astrophysics.