Barnard Comets README

Background
Edward Emerson Barnard was a prolific observer and a pioneer in the field of 
astrophotography.  He perfected the art of taking high-quality photographs of 
astronomical objects and was particularly interested in comets. The Yerkes 
files contain photographs of at least 45 comets he observed.

Someone in the mid-1930s, probably Barnard’s niece and frequent assistant Mary 
Calvert, prepared a catalogue of Barnard’s plates as well as of several other 
plate series held by the observatory.  This catalog is known as the “Barnard 
Logbook.” 

The Barnard Logbook contains nine sections giving the information on the 
plates in a number of plate series.  The sections are:
  I. MILKY WAY, MOON, etc with the Bruce Photographic Telescope 1904 - 1922. 
     [Series B10, B6, B3, etc]. Pages 1-85. Additional plates added on pages 98d-98m.
  Ia. MILKY WAY, etc.  Positives and 2nd negatives of photographs made with the 
     Willard lens of the Lick Observatory 1892 - 1895 (original negatives at Lick 
     Observatory).  [Series L].  Pages 90-97. Additional plates 98a-98c.
  II. CLUSTERS, NEBULAE, etc. - made with the 40-inch refractor, with color filters, 
     1900-1922. [Series F].  Pages 104-119.
  III. PLANETS, etc. - made with the 40-inch refractor. using an enlarging lens and 
     color filter, 1905-1910. [Series FP].  Pages 124-127. Additional plates 182-183
  IV. PLANETS, CLUSTERS, NEBULAE, etc. - made with the 60-inch reflector of the Mount 
     Wilson Observatory, November 1911 [Series 60-PN]. Pages 131-133
  V. COMETS - made with the Bruce Photographic telescope, etc., 1900-1922. [Series C]. 
     Page 138-165.  Additional plates 176-177.
  Va. COMETS - Positives and 2nd negatives of photographs made with the Willard lens 
     of the Lick Observatory 1889 - 1894 (original negatives at Lick Observatory). 
     [Series LC]. Pages 170-172.
  VI. CLUSTERS, NEBULAE, etc. - made with the 40-inch refractor, with color filter, 
     by G.W.Ritchey in 1900 and 1901. [Series F Ry].  pages 98r-98t.
  VII. HALLEY’S COMET - photographs by j. C. Duncan [Series HD].  Pages 174-175.
  VIII. Photographs made by F.R. Sullivan, with a 6-inch lens attached to the 40-inch 
     tube during exposures for spec. [Series S].  Page 178-180

The remainder of this README file refers to the Section V plates, those of comets. 
Plates of 45 comets are included.

Telescopes
Most of the plates considered here were taken by E. E. Barnard with the the Bruce 
Photographic Telescope (see Barnard, Astrophys. J., 21, 35-48, 1905). This instrument, 
installed in 1904 April, actually consisted of three co-mounted telescopes: two 
photographic refactors of 10- and 6¼-inch aperture and a five-inch guiding telescope.  
The original 6¼-inch lens was replaced in 1905 with a 6-inch UV transmitting one.  
A number of other lenses were used from time to time to obtain plates that are also 
included in the log. This is particularly the case for Barnard’s earliest Yerkes 
plates taken of seven comets with a variety of lenses before the Bruce Telescope 
was available.  The telescopes used as recorded in the log are:
  10-inch Bruce: 10-in (25-cm) aperture and 50-in (128-cm) focal length giving a 
     scale of 160"/mm (1.1 degrees per inch)
   6-inch Bruce: 6-in (15-cm) aperture and 31-in (79-cm) focal length giving a 
     scale of 260"/mm (1.8 degrees per inch)
   3-inch Ross:  3-in photographic and photovisual lenses with scale of 390"/mm 
     (2.5 degrees per inch)   
   Clark lens: 3.4-inch (8.5-cm) aperture and 20-inch (51-cm) focal length 
     giving a scale of about 6.8'/mm (2.8 degrees per inch).
   Hale lantern lens:  1.6-inch (4-cm) aperture and 6.3-in (16-cm) focal 
     length giving a scale of about 20'/mm (9 degrees per inch)
   Dr. Mitchell's Goerz lens: 1.25-inch (3.18 cm) and 6-inch (15-cm) focal length
   
Other lenses mentioned in various sources: 6.25-inch Voightlander, 4.5-inch 
Brashear lens, Brashear lens #2, Brashear lens #4.

Observatory location was: longitude = 88° 33’ W, latitude = 42° 34’ N..

Plates and Plate Series
The large 12 x 12-inch plates are listed as “a” plates in the Logbook and were 
taken with the 10-inch lens (the B10 telescope).  The 8 x 10-inch plates are 
denoted “b” plates and were taken and with the 6-inch lens (the B6 telescope).  
The smaller “c” and “d” plates were taken with smaller lenses, most often the 
Clark lens (6½ x 8½-inch plates) or the Hale lantern lens (plates about 4 x 5-inch). 

In most cases multiple plates were taken with two, and often more, lenses 
simultaneously (which allows plate defects to be easily distinguished from 
true celestial objects).  Simultaneous plates have the same plate number.  
For example, there are three plates of Comet Daniel numbered C-36, one with 
the 10-inch lens, one with the 6 inch lens and one with the 3.4-inch Clark lens. 
They can be distinguished by their different sizes.
 
The Logbook
The Barnard Logbook is at the University of Chicago. The entire book has been 
scanned and is available on-line. However, the book contained a number of inserted 
notes and these were also scanned which somewhat confuses browsing the entries.  At 
times, information written on the plate or on the plate envelope differs from that 
in the logbook.

The Searchable files
There are two csv files that can be viewed or downloaded to search for plates of 
interest.  The “Full.csv” file lists the plates by plate number.  The “By-Dec.csv” 
file is the Full.csv file sorted by decreasing declination which allows a quicker 
way to see if the collection contains plates of interest.  An "Additional Notes.csv“ 
file provides any detailed notes on a plate from the logbooks that are not 
included in the notes of the Full.csv file. Any cell in a csv that is blank 
indicates there is no information available or it has yet to be calculated 
(for example, a time of mid-exposure when the start time and end time are known).

Description of the columns of the csv files
Record number - Record number in the catalog
Plate series - All are the Barnard C series
Plate number - Identifying number of the plate
Date - The date the plate was exposed as recorded. 
Object - The target field or object of the exposure.  
RA - Right ascension of the plate center 
Dec - Declination of the plate center 
Length of exposure -  Exposure length (in minutes unless otherwise noted)
Exposure Start - Start time of the exposure (usually as recorded on plate) 
Exposure Mid - Mid-time of the exposure
Exposure End - End time of the exposure (usually as recorded on plate)
Time type -  Type of time uses (usually Central Time)
Emulsion + Filter - Emulsion type and filter used (if any)
Plate dimensions - Physical size of the plate, in inches
Observer - Recorded observer (see list below)
Location -  Location of plate when this catalogue was prepared: Yerkes, Univ.
     of Chicago.  Blank indicates that plate not in vault.  X indicates plate has 
     been discarded
Notes - Notes recorded in the logbook.  Longer notes are in the Additional-
     Notes file

Observer code:  EEB = E. E. Barnard, AMJ = Jay (possibly A. H. Joy), AvM = Adrian 
     van Maanen, VB = van Biesbroeck

File prepared:  2022 October 12