636 S. Alameda Blvd. Las Cruces, New Mexico August 3, 1953 Dre. I. C. Slipher, and A. G. Wilson Lowell Observatory Flagstaff, Arizona Dear Dre. Slipher and Wilson! Thank you for sending the Mars Circular. I am enclosing some carbon copies of letters to Dr. Pettit, and to Dr. Kuipsr. Sine© there is very little of a personal nature in each, and since the one to Dr. Kuiper, particularly, contains an outline of basic planetary-teles cope principles and how to use a large reflecting telescope effectively, I thought it would do no harm to send a few conies around to those indicated. This is a plea for the use of eccentric diaphragms, and I hope that this information will encourage observation with the large reflectors in a manner which will give pay-off results. Sincerely yours. cc CLYEE W. TOMBAUGH Dr. A. a. Wilson Mr. Roger L. Putnam P.S. I have heard that a large, final report on the Planetary Atmospheres Study Project has been published. If so, may I have a copy sent to me? Thanks.
