Yerkes 41-inch README

The Telescope:
The Yerkes Observatory 41-inch Cassegrain reflector telescope was installed in late 
1969.  It has a clear aperture of 40 inches, but was designated the "41-inch" to 
distinguish it from the Yerkes 40-inch refractor.  With the normal f/8 optical 
configuration the focal length is 320-inch (810-cm) giving a scale of 25"/mm 
(0.175'/inch).  An alternative f/13 configuration was occasionally used.  The 
telescope is described in ADS under bibcodes 1969BAAS....1..135O and 
1970BAAS....2..170O.  The observatory location is:  longitude = 88° 33’ W, 
latitude = 42° 34’ N.

The Plates
About 1600 plates were taken with this telescope in the period 1969-1997.  Most 
were 3.25 x 4.25-inch in size with a plate scale of 25"/mm, which gives a field 
of about 0.5 degrees in Dec x 0.7 degrees in RA. A few plates are 8 x 10-inch 
in size and a few were taken with the f/13 optical configuration.  Plates taken 
by George Corso (GC) and his collaborators were purchased by them and he removed 
them from the Yerkes archive for his use sometime in the 1990s (e-mail communication 
from Corso, February 2011).     
     
The Logbooks
There are two logbooks that cover the plate collection.  Book 1 contains plates 
1 (1969-12-16) through 1110 (1980-11-06).  Book 2 contains plates 1111 (1980-11-06) 
through 1528 (1997-06-14).  There are two supplemental log books for the plates 
taken by Richard A White (1973) and David G. Monet (1974) as well as a folder 
summarizing Monet's plates. All log books are at the University of Chicago.  
They have been scanned and the scans are available on-line.
     
Notes in Book 1 indicate it was misplaced 1973 May to 1974 September.  Plates 
numbered 259a to 259f, 259N-1 to 250N-25, 261a to 261w and 269 - 272 were taken 
during this period but not entered in the logbook until it was found. They were 
given plate numbers and added to the book in 2012 and 2016.  Information on these 
plates are in both Book 1 and Book 2.  A few plates in this time period are not 
numbered in chronological order.  

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" 
file provides any detailed notes on a plates from the logbooks that are not 
included in the notes of the Full.csv file. Any cell in a csv file 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 - Yerkes 41-inch = Y41
Plate number - Identifying number of the plate
Date - The date the plate was exposed as recorded.  Many dates are listed in 
   double-day format. 
Object - The target field or object of the exposure.  A few plates have multiple   
   fields
RA - Right ascension of the plate center (usually 1975 or 2000) 
Dec - Declination of the plate center (usually 1975 or 2000) 
Length of exposure -  Exposure length (in minutes unless otherwise noted)
Exposure Start - Start time of the exposure as recorded 
Exposure Mid - Mid-time of the exposure (if recorded or calculated)
Exposure End - End time of the exposure (when recorded)
Time type -  Type of time uses (usually UT)
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 1 (first 
floor of the Yerkes plate vault), Yerkes 2 (second floor), U. Chicago, KC 
   (borrowed by Kyle Cudworth).  Blank indicates that plate not in vault.
Notes - Notes recorded in the log book.  Longer notes are in the 
Additional Notes file

Observer code:  
AC= Adelos Camlet; AF = Albert Fu; AJ = Andy Jankevics; ARC = Arnab Rai Chouduri; 
AVK = Andrew Klein; AW = Adlan Wirth; BB= Bruce Bentz; BFJ = Burt Jones; 
BG = WG = Bill Glaccum; BR = Bernard Rauscher; CLB = Courtland Bohn; CMT = Charlie 
Telesco; CO = GC = GJC = George Corso; DB = Dinshaw Balsara; DGM = Dave Monet; 
DH = Donald Hamilton; DLT = David L. Talent; DP = Dan Peterson; DW = DEW = 
Dan Welty; EA = Elise Albert; EC = Evangelos Chaliasos; ES = Ed Shayq; 
GB = Geoffrey Burks; GT = Garmet Toomey; HH = Harald Hammy; HH1 = H. Henning, 
HM = Harvey Mosely;  HR; JK = JBK = Jocelyn B. Keene; JWB = John W. Briggs; 
JU = Joe Ulowetz; KC = Kyle Cudworth; Nachman; NRW = Walborn; RF = Richard Fox; 
RJB; RM = Robert Managan; RM = Ron Myers (UW Madison); RR = Rick Rees; RS = RCS = 
Ron Stone; RW = RAW = Richard White;  RK = Richard Kron; RY = HR = Rymer; SC = 
Sean Casey; SM = Steve Majewski; SW = SEW = Stan Whitcomb; TA = Tom Adams; WvA = 
William van Altena; Paul Nachman


File prepared:  2022 October 12