Telescope Data Center Harvard Plate Collection Harvard-Smithsonian Center for Astrophysics
Harvard Observatory Plate Stacks
B Series Characteristics


Plate Size Plate Scale Telescope Focal Length
8x10, 4x5 179"/mm 8-inch Bache Doublet, Voigtländer, reworked by Clark 44 inches


Plate nos.LocationDates
1- 3186Cambridge1885-08-04 - 1888-11-13
3187- 3296Willows, CA (ecl.)1888-12-17 - 1889-01-28
3301- 5845Mt. Harvard, Peru1889-05-09 - 1890-10-05
5846-37263Arequipa1891-03-27 - 1905-11-28
37264-37280Cambridge1906-05-18 - 1907-01-06
37281-45181Arequipa1907-04-20 - 1914-12-23
45269-53754Arequipa1915-07-04 - 1923-05-20
53755-76864Bloemfontein1930-01-20 - 1954-03-08

Online Searchable catalog

all-sky map
Maps of spatial and temporal distribution
histogram by year
Histogram by year


[The logged right ascension and declination were assumed to be at the equinox of date]

in Stacks

Plate SizeLocationNumbers
8x10third floorall
4x5third floorall

Card Catalog:

complete; there is also an Approach database of the blue plates.

Record Books:

(75) 1-76850 (no records for 45182-45268; these plates exist)

Record Sheets:



The 4x5 plates are spectra. The 8x10 spectrum plates furnish the best routine information on the spectra of southern stars down to about the ninth mag­nitude. Some of them are of the most excellent quality.

The first three Bache books were used to record all experiments with dry plate photographs, and contain early records for several plate series, including an early A series, C and D.

The Bache was returned to Cambridge for repairs 1914-12-24 - 1915-06-21. During this period plates as indicated above were taken. The plates exist, but no records can be found. Catalog cards have been made from information on plate jackets.

N.B.: There are large numbers of plates missing (e.g. 51215-51420; 51801-52026).

On many of the direct plates, the bright stars have prismatic companions (Pickering wedge).