Ute Esser

Astronomy and Astrophysics Abstracts, which has appeared in semi-annual volumes since 1969, is de­ voted to the recording, summarizing and indexing of astronomical publications throughout the world. It is prepared under the auspices of the International Astronomical Union (according to a resolution adopted at the 14th General Assembly in 1970). Astronomy and Astrophysics Abstracts aims to present a comprehensive documentation of literature in all fields of astronomy and astrophysics. Every effort will be made to ensure that the average time interval between the date of receipt of the original literature and publication of the abstracts will not exceed eight months. This time interval is near to that achieved by monthly abstracting journals, com­ pared to which our system of accumulating abstracts for about six months offers the advantage of greater convenience for the user. Volume 18 contains literature published in 1976 and received before March 1, 1977; some older liter­ ature which was received late and which is not recorded in earlier volumes is also included.

Astronomy and Astrophysics Abstracts, which has appeared in semi-annual volumes since 1969, is de­ voted to the recording, summarizing and indexing of astronomical publications throughout the world. It is prepared under the auspices of the International Astronomical Union (according to a resolution adopted at the 14th General Assembly in 1970). Astronomy and Astrophysics Abstracts aims to present a comprehensive documentation of literature in all fields of astronomy and astrophysics. Every effort will be made to ensure that the average time interval between the date of receipt of the original literature and publication of the abstracts will not exceed eight months: This time interval is near to that achieved by monthly abstracting journals, com­ pared to which our system of accumulating abstracts for about six months offers the advantage of greater convenience for the user. I, 1980; some older Volume 27 contains literature published in 1980 and received before August literature which was received late and which is not recorded in earlier volumes is also included. We acknowledge with thanks contributions to this volume by Dr. J. Bouska, Prague, who surveyed journals and publications in Czech and supplied us with abstracts in English.

Astronomy and Astrophysics Abstracts, which has appeared in semi-annual volumes since 1969, is devoted to the recording, summarizing and indexing of astronomical publications throughout the world. According to a resolution adopted at the 14th General Assembly in 1970 it is prepared under the aus- pices of the International Astronomical Union. Astronomy and Astrophysics Abstracts aims to present a comprehensive doc- umentation in all fields of astronomy and astrophysics. It is due to the ever- lasting increase of the bulk of material that the information content of our regular volumes is growing seriously. Therefore, the need for detailed index informations allowing the performance of retrospective literature searches be- comes more and more important. Volume 23/24-the second General Index of Astronomy and Astrophysics Abstracts - contains author and subject indexes to volumes II -14 and, respectively, 17-22. Thus, the astronomical and astrophysical literature of the whole five-year period 197 4 -1978 is cov- ered by this volume. It is a pleasure to express our gratitude to Ms. Helga Ballmann, Ms. Monika Betz, Mr. Gernot Burkhardt, Ms. Lore Kiefert, Ms. Dagmar Roeder, Ms. Dimitra Roussou, and Mr. Werner Sanns for their kind support during the detailed preparation steps of the indexes.

Astronomy and Astrophysics Abstracts, which has appeared in semi-annual volumes since 1969, is de­ voted to the recording, summarizing and indexing of astronomical publications throughout the world. It is prepared under the auspices of the International Astronomical Union (according to a resolution adopted at the 14th General Assembly in 1970). Astronomy and Astrophysics Abstracts aims to present a comprehensive documentation of literature in all fields of astronomy and astrophysics. Every effort will be made to ensure that the average time interval between the date of receipt of the original literature and publication of the abstracts will not exceed eight months. This time interval is near to that achieved by monthly abstracting journals, com­ pared to which our system of accumulating abstracts for about six months offers the advantage of greater convenience for the user. Volume 20 contains literature published in 1977 and received before February 20, 1978; some older literature which was received late and which is not recorded in earlier volumes is also included. We acknowledge with thanks contributions to this volume by Dr. J. BouSka, Prague, who surveyed journals and publications in Czech and supplied us with abstracts in English, and by Prof. P. Brosche, Bonn, who supplied us with literature concerning some border fields of astronomy.