Documents / FOIA release
This Central Intelligence Agency file, dated 29 December 1952, holds a thank-you letter from H. Marshall Chadwell to Professor J. Allen Hynek of Ohio State University. With it is Hynek's earlier letter to Chadwell, which puts in writing the astronomical calculations he had first given by telephone. Hynek concludes that a theodolite sighting made from Limestone and Presque Isle was the planet Jupiter. He bases this on how closely its position and its rates of motion matched the computed ones. Chadwell writes that he agrees with the findings.
Read from the scan by GLM-OCR; expect the odd misread word.
Dr. H. M. Chadwell Apt. 1217 2800 Quebec Street, N. W. Washington 8, D. C.
Dear Dr. Chadwell:
In pursuance of our telephone conversation of the other day, and in accordance with your request, I am confirming in writing the results I transmitted to you over the phone.
It is well known that in theodolite observations, elevations can be generally obtained more accurately than the azimuths since the former depend only on accurate leveling but the latter depend upon a determination of the true north. Since most theodolite observers are interested in relative rates and not in absolute positions, it is no surprise that they do not pay too much attention to the exact determination of their zero points. Further, it is quite easy for even an observer of some experience to make an error in reading of some multiple of whole degrees. The observation made at Limestone, therefore, can very well be assumed to have both a zero point error and an incorrect scale reading.
At the mean time of observation, calculations made at the observatory here show that Jupiter had, at Presque Isle, an azimuth of $ 1 6 3^{\circ} $ and an elevation of $ 5 8. 5^{\circ} $ . This alone is sufficiently close to the mean of the readings from two stations to serve as strong evidence that the object observed was Jupiter. However, the clinching argument comes when one compares Jupiter's rate of motion in elevation and azimuth during the observation and the rates noted on the theodolite, at Presque Isle. The computed increment in elevation was 0.2 degrees (as compared to the observed 0.3 degrees) and the corresponding increment in azimuth was 1.8 degrees (as against the observed 1.9 degrees). In view of this strikingly close agreement in rates as well as general position in the sky, it would be an outrage to probability theory to consider that the object observed was anything other than the time-honored planet Jupiter. The prosecution rests its case!
Wishing you the very best greeting of the season, I remain.
Sincerely yours,
J. Allen 17
J. Allen Hynck Assistant Dean and Professor of Astronomy Not linked to a story yet.
FOIA release, from the cia-readingroom collection. The PDF is mirrored here; the original link is above. The text was read from the page images by GLM-OCR; expect the odd misread word. 2 pages are in the text index: search them above, or from the library's search.