Photographs of Stars, Star-Clusters and Nebulae

by Roberts, Isaac

• ISBN13: 9781108015233
• ISBN10: 1108015239
• Edition: Reprint
• Format: Paperback
• Copyright: 2010-10-31
• Publisher: Cambridge Univ Pr

Summary

A geologist and fellow of the Royal Astronomical Society, Isaac Roberts (1829-1904) made significant contributions to the photography of star-clusters and nebulae. By championing reflecting rather than refracting telescopes, Roberts was able to perceive previously unnoticed star-clusters, and was the first person to identify the spiral shape of the Great Andromeda Nebula. Roberts' use of a telescope for photographing stars, and a long exposure time, provided greater definition of stellar phenomena than previously used hand-drawings. Although Roberts' conclusions about the nature of the nebulae he photographed were not always correct, the book is significant for the possibilities it suggests for nebular photography. Published in 1893 and 1899, the two-volume Photographs of Stars represents the summation of his work with his assistant W. S. Franks at his observatory in Crowborough, Sussex. Volume 2 contains 29 plates of stars, and his conclusions about their origins and nature.

Table of Contents

Preface;

List of the plates

Instruments

List of abbreviations adopted in this work

The negatives

Epoch of the Fiducial stars, A.D. 1900

Table for converting the measured right ascensions

Deterioration of the negatives

Effects of atmospheric glare and of diffraction upon the films of photographic plates

Arrangement of the plates

Method for micro-puncturing the photographic discs of stars on plates

Star catalogues and photographic charts

Duration of the effective exposures given to photographic plates in the 20-inch reflector

Are the millions of stars and the numerous nebulosities limited in number and extent

The evolution of stellar systems

Inferences suggested by examination of the photographs

Description of the photographs

M.31. Andromedae

M.99 Virginis

M.51 Canum Venaticorum

Region of 7 Cassiopeiae

Nebulae in the Pleiades

M.42. Orionis

General conclusions concerning the evolution of stellar systems

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