QC 351 A7 no. 07 / The Meinel Reducing Camera for the U. S. Naval Observatory's 60-inch
telescope, Flagstaff, Arizona, comprises an f /10 collimator designed by
Meinel and Wilkerson, and a Leica 50-mm f/2 Summicron camera lens. The
collimator consists of a thick, 5-inch field lens located close to the focal plane of the telescope, plus four additional elements extending toward
the camera. The collimator has an efl of 10 inches, yielding a 1-inch exit
pupil that coincides with the camera's entrance pupil, 1.558 inches beyond
the final surface of the collimator. There is room between the facing lenses
of the collimator and camera to place filters and a grating. The collimated
light here is the best possible situation for interference filters.
Problems of the collimator design work included astigmatism due to the
stop's being so far outside the collimator, and field curvature.
Two computer programs were used in development of the collimator design.
Initial work, begun in 1964, was with the University of Rochester's ORDEALS
program (this was the first time the authors had used such a program) and was
continued through July, 1965. Development subsequently was continued and
completed on the Los Alamos Scientific Laboratory's program, LASL. The final
design, completed January 24, 1966, was evaluated with ORDEALS.
This project gave a good opportunity to compare ORDEALS, an "aberration"
program, with LASL, a "ray deviation" program. It was felt that LASL was the
superior program in this case, and some experimental runs beginning with flat
slabs of glass indicated that it could have been used for the entire development of the collimator.
Calculated optical performance of the design indicated that the reducing
camera should be "seeing limited" for most work. Some astigmatism was apparent, but the amount did not turn out to be harmful in actual astronomical use.
After the final design was arrived at, minor changes were made to accommodate actual glass indices of the final melt, and later to accommodate slight
changes of radii and thicknesses of the elements as fabricated. An additional
small change in spacing between two of the elements was made at the observatory after the reducing camera had been in use for a short time.
The fabricated camera is working according to expectations. Some photographs are included in the report to illustrate its performance and utility.
| Identifer | oai:union.ndltd.org:arizona.edu/oai:arizona.openrepository.com:10150/621602 |
| Date | 28 February 1968 |
| Creators | Meinel, Aden B., Wilkerson, Gary W. |
| Publisher | Optical Sciences Center, University of Arizona (Tucson, Arizona) |
| Source Sets | University of Arizona |
| Language | en_US |
| Detected Language | English |
| Type | Technical Report |
| Rights | Copyright © Arizona Board of Regents |
| Relation | Optical Sciences Technical Report 07 |
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