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NEW MEXICO COLLEGE
OF AGRICULTURE AND MECHANIC ARTS
PHYSICAL SCIENCE LABORATORY
11 November 1957 LAS ""<="•• "• M-
PERSONAL m~-» ••«•"
Dr. Geoffrey Keller
Program Director for Astronomy
National Science Foundation
Washington 25, D. C.
Dear Geoffrey:
I beg your patience to read through this long letter, but after you have done
so, you will understand why.
I want to thank you for your kind letter of September 30th. I asked Mr.
Bradford A. Smith, my colleague, to write to you (October 26) describing the properties of his proposed device for recording finer planetary detail and comparing its
features with other systems, such as Seyfert's and DeWitt's at Nashville, the image
Luxnicon at Flagstaff and Leighton' a at Mount Wilson.
The device itself was Smith' s idea, and I think the most promising one to
date for the very difficult problem of recording finer planetary detail. I am building
the telescope at my own expense and personal time during evenings and week ends.
My experiments over the last 15 years on off-axis apertures with my own smaller
telescopes, and at McDonald with Dr. Kuiper on the 82-inch in 1950, etc. have greatly
encouraged the working out of a new reflector optics design especially suited for the
fine planetary detail problem.
During the opposition of 1954, I devoted a great deal of my personal time to
observing Mar* with the Lowell 24-inch refractor and my own 8-inch clear aperture
off-axis, long focal length Newtonian reflector in Las Cruces. The Search for Natural
Earth Satellites Project required that two weeks of each month be spent in residence
at Flagstaff, and two weeks at Las Cruces. This provided an excellent opportunity
to compare the Martian detail visible throughout the opposition with the two instruments.
Flagstaff had the advantage of 3,000 feet more altitude, but the planet was 3 degrees
higher in Las Cruces.
As is well known Dr. Lowell, in his day, obtained his best visual observations
with a 16-inch aperture on the 24-inch refractor. An iris diaphram in front of the objective is easily operated from the eyepiece with an indicator of the aperture from 24 to 6
inches. The sliphers habitually use this aperture also. I found that the best views
were obtained with apertures varying from 13 to 18 inches. Twenty inches was definitely
too much even on very good nights, which I partly blame on the difference in lateral
scale of image in the different wave lengths, caused by the chromatic difference in
focal length.
Object Description
| Title | Keller, Geoffrey, 1957-1959 |
| Alternate Title | Sub-subseries: Correspondence |
| Series | NMSU Physical Science Lab, Box 083, Folder 021 |
| Creator | Tombaugh, Clyde William, 1906-1997; Keller, Geoffrey, 1918- |
| Subject | Astronomical instruments; Telescopes; Mars (Planet)--Observations; Telescopes and optics--Design and construction; Planets--Observations; Planets--Research; Research and development projects; Evaluation; Mars (Planet)--Observations; Mars (Planet)--Photographs; Progress; Mirrors; Sputnik satellites; Minerals |
| Relevant Names | National Science Foundation (U.S.) (U.S.); Washington (D.C.); Smith, Brad, 1931-2018; Seyfert, Carl Keenan; DeWitt, John H. (John Hibbett), 1906-1999; Leighton, Robert B.; Flagstaff (Ariz.); Mount Wilson and Palomar Observatories; Kuiper, Gerard P. (Gerard Peter), 1905-1973; Las Cruces (N.M.); Slipher, Earl C.; Slipher, Vesto Melvin, 1875-1969; Meinel, Aden B.; Wilson, Albert George, 1918-; Lowell Observatory; Strughold, Hubertus, 1898-1986; Simons, David G. G.; Holloman Air Force Base (N.M.); Rand Corporation; Shapley, Harlow, 1885-1972; Leonard, Frederick C., 1896-1960; Popper, Daniel M.; Edmondson, Frank K. (Frank Kelly), 1912-2008; Hess, Seymour L.; Seyfert, Carl Keenan; Hardie, Robert; Douglas, Charles; Carpenter, Edwin Francis; Kuiper, Gerard P. (Gerard Peter), 1905-1973; Hiltner, Al; Russell, John A.;Reaves, Gibson; Lowell, Percival, 1855-1916 |
| Digital Publisher | New Mexico State University Library |
| Collection | NMSU Department of Astronomy: Clyde W. Tombaugh Papers |
| Source | Scan produced from physical item held by the NMSU Library Archives & Special Collections Department |
| Type | Text |
| Format | image/tiff |
| Language | eng |
Page Description
| Title | Page 1 |
| Series | NMSU Physical Science Lab, Box 083, Folder 021 |
| Creator | Tombaugh, Clyde William, 1906-1997 |
| Subject | Astronomical instruments; Telescopes; Mars (Planet)--Observations |
| Relevant Names | National Science Foundation (U.S.) (U.S.); Washington (D.C.); Smith, Brad, 1931-2018; Seyfert, Carl Keenan; DeWitt, John H. (John Hibbett), 1906-1999; Leighton, Robert B.; Flagstaff (Ariz.); Mount Wilson and Palomar Observatories; Kuiper, Gerard P. (Gerard Peter), 1905-1973; Las Cruces (N.M.); Lowell, Percival, 1855-1916 |
| Date Original | 1957-11-11 |
| Digital Publisher | New Mexico State University Library |
| Collection | NMSU Department of Astronomy: Clyde W. Tombaugh Papers |
| Digital Identifier | Ms0407pp083021_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 | NEW MEXICO COLLEGE OF AGRICULTURE AND MECHANIC ARTS PHYSICAL SCIENCE LABORATORY 11 November 1957 LAS ""<="•• "• M- PERSONAL m~-» ••«•" Dr. Geoffrey Keller Program Director for Astronomy National Science Foundation Washington 25, D. C. Dear Geoffrey: I beg your patience to read through this long letter, but after you have done so, you will understand why. I want to thank you for your kind letter of September 30th. I asked Mr. Bradford A. Smith, my colleague, to write to you (October 26) describing the properties of his proposed device for recording finer planetary detail and comparing its features with other systems, such as Seyfert's and DeWitt's at Nashville, the image Luxnicon at Flagstaff and Leighton' a at Mount Wilson. The device itself was Smith' s idea, and I think the most promising one to date for the very difficult problem of recording finer planetary detail. I am building the telescope at my own expense and personal time during evenings and week ends. My experiments over the last 15 years on off-axis apertures with my own smaller telescopes, and at McDonald with Dr. Kuiper on the 82-inch in 1950, etc. have greatly encouraged the working out of a new reflector optics design especially suited for the fine planetary detail problem. During the opposition of 1954, I devoted a great deal of my personal time to observing Mar* with the Lowell 24-inch refractor and my own 8-inch clear aperture off-axis, long focal length Newtonian reflector in Las Cruces. The Search for Natural Earth Satellites Project required that two weeks of each month be spent in residence at Flagstaff, and two weeks at Las Cruces. This provided an excellent opportunity to compare the Martian detail visible throughout the opposition with the two instruments. Flagstaff had the advantage of 3,000 feet more altitude, but the planet was 3 degrees higher in Las Cruces. As is well known Dr. Lowell, in his day, obtained his best visual observations with a 16-inch aperture on the 24-inch refractor. An iris diaphram in front of the objective is easily operated from the eyepiece with an indicator of the aperture from 24 to 6 inches. The sliphers habitually use this aperture also. I found that the best views were obtained with apertures varying from 13 to 18 inches. Twenty inches was definitely too much even on very good nights, which I partly blame on the difference in lateral scale of image in the different wave lengths, caused by the chromatic difference in focal length. |
