No CrossRef data available.
Published online by Cambridge University Press: 26 July 2016
The Sonneberg collection numbers about 250,000 photographic plates; those of the Sonneberg Sky Patrol and Field Patrol reach back into the past as far as 1926. The Sky Patrol aims at providing a continuous record of the whole northern sky; the Field Patrol, of 81 fields selected along or near the Milky Way.