76^x *^\ ^-' g-
Chapter 8
The Photographic Search Begins
When the photographing began in April, my instructions from
Slipher were; "Do the regions in Gemini, and proceed eastward
along the Ecliptic as rapidly as possible." There was no warning
about the improper procedures and strategy.
The Gemini region was already about ninety degrees west of
the opposition point. It was not until the end of the June
lunation that I succeeded in catching up. The opposition point
itself sweeps eastward through the constellations at a rate of
thirty degrees each month. This is caused by the Earth's motion
of revolution around the sun.
On June 7, 1929, V. M. Slipher attached the 5-inch Cogshall
Camera on the side of the 13-inch telescope tube. The purpose
was to serve for confirmation of planet suspects seen on the 13-
inch plates. Half of the June lunation work was over. This was
a beautiful camera with a field a little wider than the 13-inch.
The Cogshall camera took eight by ten inch plates. The focal
length was almost exactly one-third that of the 13-inch. Consequently, the angular scale was one-third as much; namely: one de-
degree was one centimeter across instead of three. This means
Tombaugh, Clyde William, 1906-1997. Out of the darkness: The planet Pluto--Manuscripts; Books
Digital Publisher
New Mexico State University Library
Collection
NMSU Department of Astronomy: Clyde W. Tombaugh Papers
Digital Identifier
Ms0407pp053004_0010001.tif
Source
Scan produced from physical item held by the NMSU Library Archives & Special Collections Department
Type
Text
Format
image/tiff
Language
eng
OCR
76^x *^\ ^-' g-
Chapter 8
The Photographic Search Begins
When the photographing began in April, my instructions from
Slipher were; "Do the regions in Gemini, and proceed eastward
along the Ecliptic as rapidly as possible." There was no warning
about the improper procedures and strategy.
The Gemini region was already about ninety degrees west of
the opposition point. It was not until the end of the June
lunation that I succeeded in catching up. The opposition point
itself sweeps eastward through the constellations at a rate of
thirty degrees each month. This is caused by the Earth's motion
of revolution around the sun.
On June 7, 1929, V. M. Slipher attached the 5-inch Cogshall
Camera on the side of the 13-inch telescope tube. The purpose
was to serve for confirmation of planet suspects seen on the 13-
inch plates. Half of the June lunation work was over. This was
a beautiful camera with a field a little wider than the 13-inch.
The Cogshall camera took eight by ten inch plates. The focal
length was almost exactly one-third that of the 13-inch. Consequently, the angular scale was one-third as much; namely: one de-
degree was one centimeter across instead of three. This means
