This book is for the amateur astronomer who wants to know about the astrophysical nature of deep sky objects. The information is presented in a concise format and is equally valuable when used as background reading or alternatively at the telescope eyepiece or while waiting for astroimaging exposures to complete in the field.

The past decades have seen an unprecedented increase in professional astronomers’ understanding of astrophysical objects. However, generally this information is contained in journal publications that most amateur astronomers either do not have access to or would find difficult to read. In this book, basic data on each object (e.g. magnitude, location, distance, age if known) is presented in a way that allows the reader to quickly access the information. This is followed by some remarks that capture the most fascinating astrophysical facts.

Although there are thousands of deep sky objects observed or imaged by astronomers, only a small number of these are commonly observed or imaged by a wide audience. Thus, coverage here is limited to the most commonly imaged or observed objects in the Northern Hemisphere, along with 30 from the Southern Hemisphere, many of which are visible from the southern limits of the United States. An enhancement for the 3rd Edition is the addition of objects that rounds out the book’s coverage to also include those that are most commonly targeted by astroimagers in addition to all the commonly observed visual objects.

Dr. Warren H. Finlay is an avid amateur astronomer and author of Concise Catalog of Deep-Sky Objects: Astrophysical Information for 550 Galaxies, Clusters and Nebulae, 2nd edition. He is the recipient of the Royal Astronomical Society of Canada’s (RASC) prestigious Chant Medal for his work carried out in astronomy, as well as the Simon Newcomb Award for literary achievement in astronomy, among several other RASC awards for dark sky preservation and astronomy education. He has observed more than 4000 deep sky objects, including the entire Herschel 2500 list. He is the creator of the Brightest 2500 Northern NGC list as a modern alternative to the Herschel 2500 list. He is the visionary behind the RASC’s Black Nugget Lake Observatory, and managed the team that built the 14 foot domed observatory, visitor centre and 32” diameter custom Unyk-Drew Telescope (UDT) that saw first light in 2023. The UDT is one of the largest telescopes at a dark site in Canada available for public viewing through the eyepiece. Warren is also a national award winning astrophotographer. In his career as a Professor of Mechanical Engineering, Warren has written two other books, 13 chapters in other books, more than 220 archival journal papers, and more than 300 refereed conference publications. He has been inducted as a lifetime Fellow of the Royal Society of Canada.