Green Bank Observatory is in the state of West Virginia, in the eastern United States.
It is located in the small community of Green Bank, in Pocahontas County, within the National Radio Quiet Zone, where radio transmissions are tightly restricted to minimise interference with sensitive radio astronomy observations.
Factoids:
- 3.5–4 hours’ drive from Washington Dulles International Airport (IAD).
- Home to the 100 m Robert C. Byrd Green Bank Telescope (GBT), the world’s largest fully steerable radio telescope.
- A superb destination for anyone interested in amateur radio astronomy, with tours, exhibits, and often opportunities to see observing operations in progress.
- Also the location of the Ewen Hydrogen Horn, and the 20m Skynet radio dish, observations on which can be made by SARA members as part of their membership.
Telescopes:
Green Bank Observatory has a fascinating collection of historic and operational radio telescopes. The principal instruments are:
- 100 m Robert C. Byrd Green Bank Telescope (GBT) – the world’s largest fully steerable radio telescope. It operates from about 100 MHz to 116 GHz, making it ideal for hydrogen (1420 MHz), pulsars, galaxies, molecular lines such as the 22.235 GHz water maser, and many other radio astronomy projects.
- 43 m (140 ft) Telescope – a historic equatorially mounted telescope, now used for satellite and spacecraft-related work and engineering projects.
- 20 m Telescope – used for education, student observing, technology development and testing new receivers.
- 13.7 m (45 ft) Telescope – originally built for NASA VLBI satellite tracking and now used for solar radio observations and engineering.
- 40 Foot Telescope – a restored classic instrument used mainly for education and public observing programmes.
- 85-1 (Tatel) Telescope – famous as the telescope used by Frank Drake for Project Ozma in 1960, the first modern scientific SETI search.
- Green Bank Interferometer (GBI) and the historic Reber Telescope, commemorating the pioneering work of Grote Reber.
The 100 m GBT is the real highlight. It routinely observes:
- Neutral hydrogen at 1420.4058 MHz
- Hydroxyl (OH) masers
- 22.235 GHz water masers (the same line you’re observing with your Norsat system)
- Ammonia and many other molecular transitions
- Pulsars and fast radio bursts
- SETI observations
- Radar studies of planets and asteroids.
As a radio astronomer, you’ll almost certainly find the GBT control room, receiver laboratory, and the scale of the telescope itself to be the highlights of your visit.
Horn Antennas:
Green Bank has several historic horn antennas on display.
The main ones are:
- Ewen–Purcell Horn – this is a reconstruction/display of the horn antenna used by Harold Ewen and Edward Purcell for the first detection of the 21 cm neutral hydrogen line in 1951. It’s one of the most historically significant antennas in radio astronomy.
- “Little Big Horn” Calibration Horn – a 120-foot (37 m) horn antenna built in 1959. It was tuned to the 21 cm hydrogen line and used to measure the flux of the bright radio source Cassiopeia A, providing a calibration standard for the larger dish telescopes. It has a mouth about 13 × 17.5 feet (4 × 5.3 m).
- “Sugar Scoop” Horn – a smaller parabolic horn reflector used to measure man-made radio interference and to help characterise the radio-quiet site.
Time zones of Green Bank Observatory and Washington Dulles Airport:
Both Green Bank Observatory (West Virginia) and Washington Dulles International Airport (Virginia) are in the same time zone:
- Time zone: Eastern Time (ET)
- Summer (late March to early November): Eastern Daylight Time (EDT, UTC−4)
- Winter (early November to late March): Eastern Standard Time (EST, UTC−5)
During your trip at the end of July, both locations will be on EDT (UTC−4).
Compared with the UK:
- UK summer time (BST) is 5 hours ahead of Green Bank and Washington.
- So, when it’s 15:00 in Lichfield, it’s 10:00 in both Washington Dulles and Green Bank.