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Book contents
- Frontmatter
- Contents
- Preface
- Part 1 Optical Observatories
- Part 2 Radio Observatories
- 16 Australian Radio Observatories
- 17 Cambridge Mullard Radio Observatory
- 18 Jodrell Bank
- 19 Early Radio Observatories Away from the Australian–British Axis
- 20 The American National Radio Astronomy Observatory
- 21 Owens Valley and Mauna Kea
- 22 Further North and Central American Observatories
- 23 Further European and Asian Radio Observatories
- 24 ALMA and the South Pole
- Name Index
- Optical/ Infrared Observatory and Telescope Index
- Radio Observatory and Telescope Index
- General Index
- References
22 - Further North and Central American Observatories
from Part 2 - Radio Observatories
Published online by Cambridge University Press: 15 December 2016
- Frontmatter
- Contents
- Preface
- Part 1 Optical Observatories
- Part 2 Radio Observatories
- 16 Australian Radio Observatories
- 17 Cambridge Mullard Radio Observatory
- 18 Jodrell Bank
- 19 Early Radio Observatories Away from the Australian–British Axis
- 20 The American National Radio Astronomy Observatory
- 21 Owens Valley and Mauna Kea
- 22 Further North and Central American Observatories
- 23 Further European and Asian Radio Observatories
- 24 ALMA and the South Pole
- Name Index
- Optical/ Infrared Observatory and Telescope Index
- Radio Observatory and Telescope Index
- General Index
- References
Summary
US Naval Research Laboratory
Just after the end of the Second World War John Hagan, the head of the Centimeter-Wave Research Branch of the US Naval Research Laboratory (NRL), was looking for a new field of research in which to use his branch's experience. As a result he hit on the idea of observing astronomical sources of radio emission. Consequently Hagen and his deputy, Fred Haddock, decided to observe the Sun, not only because of its effect on the Earth's atmosphere, but because it was probably the only astronomical source observable with their type of equipment.
For their first solar observations Hagen and Haddock used parabolic antennae up to 10 ft (3 m) in diameter with receivers operating at wavelengths of 8.5 mm, 3.2 cm and 9.4 cm (frequencies of 35, 9.4 and 3.2 GHz respectively). Then in 1947 they went further and used an 8 ft diameter antenna to observe a total solar eclipse at a wavelength of 3.2 cm from on board ship in the South Atlantic. As a result they were able to conclude that the Sun, at this wavelength, was only slightly larger than the optical Sun.(1)
Unfortunately Hagen and Haddock's equipment only enabled them to observe the emission from the Sun as a whole as it did not have enough resolution to locate the exact sources of radio emission. It was clear that to locate these sources they would need a much larger dish. And if they managed to procure one they may also be able to observe other cosmic sources, as well as detecting thermal radio emission from the planets. So in the late 1940s Hagen and Haddock managed to persuade the US Navy to provide $100,000 for its purchase and, as a result, they were able to acquire a 50 ft (15 m) parabolic reflector from the Collins Radio Company designed by Ned Ashton of the University of Iowa.
This 50 ft NRL dish was made of 30 aluminium sector castings which had been bolted together. The surface was then machined to its parabolic shape to enable it to be used at wavelengths as low as 1 cm.
- Type
- Chapter
- Information
- Observatories and Telescopes of Modern TimesGround-Based Optical and Radio Astronomy Facilities since 1945, pp. 400 - 437Publisher: Cambridge University PressPrint publication year: 2016