Annals of the Deep Sky Volume 2 new and returning The knife-edge mask test always

The knife-edge mask test always under-reports the departure of the actual surface from the ideal surface

" even for other writers in the field

the reduction of differential photometry

Coordinates are the longitude of the Sun

Align a sighting device such as the Telrad® so that you can point your telescope rapidly and with assurance toward all of the Messier objects

Annals of the Deep Sky Volume 2 new and returning The knife-edge mask test alwaysBy Jeff Kanipe and Dennis Webb Product information: Softbound, 6 by 9 inches, 334 pages, first published 2015, black & white. Annals of the Deep Sky is a comprehensive reference that guides amateur and semipro astronomers into every mind boggling corner of the observational universe. Each volume presents extensive descriptions of prominent stars and deep sky objects. No other popular work in astronomy provides the comprehensive historical background