140 Foot Telescope, First Observations, 23 May 1965

Although construction on the 140 Foot telescope was "completed" in February 1965, NRAO staff still had electronics and other work to do before it was fully operable, and the telescope was not dedicated until October of 1965. However, on 23 May 1965, Sebastian von Hoerner made the first observations with the 140 Foot, measuring occultations of radio sources by the Moon at 234, 256 and 405 Mc. He said, "An occultation of a radio source by the Moon occurs only at a very specific time. If you miss it and want to repeat it, you must wait the 19 years through a lunar cycle. In May 1965, a good occultation was just coming up. I wanted to grab it, and I did." The photo shows ongoing work on the telescope on 20 May 1965, with a thumbnail inset of von Hoerner.

Records of the NRAO

NRAO/AUI/NSF

Photo from the Archives, NRAO eNews V18#5, 25 April 2025

Still Image

GB64-01709withGB65-02299.jpg

1965-05-20

1965-05-23

NRAO/AUI/NSF

GB64-01709

GB65-02299

Photographs Series

140 Foot Telescope Unit

2A