introduction to school n.
Download
Skip this Video
Loading SlideShow in 5 Seconds..
Introduction to School PowerPoint Presentation
Download Presentation
Introduction to School

Loading in 2 Seconds...

play fullscreen
1 / 7

Introduction to School - PowerPoint PPT Presentation


  • 78 Views
  • Uploaded on

Introduction to School. Tomas E. Gergely Summer School on Spectrum Management and Radio Astronomy Green Bank, June 2002. Spectrum Management.

loader
I am the owner, or an agent authorized to act on behalf of the owner, of the copyrighted work described.
capcha
Download Presentation

PowerPoint Slideshow about 'Introduction to School' - paiva


An Image/Link below is provided (as is) to download presentation

Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.


- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -
Presentation Transcript
introduction to school

Introduction to School

Tomas E. Gergely

Summer School on Spectrum

Management and Radio Astronomy

Green Bank, June 2002

spectrum management
Spectrum Management

Radio Frequency Management Is Done by Experts Who Meld Years of Experience With a Curious Blend of Regulation, Electronics, Politics and Not a Little Bit of Larceny. They Justify Requirements, Horse-trade, Coerce, Bluff and Gamble With an Intuition That Cannot Be Taught Other Than by Long Experience

Vice Admiral Jon L. Boyes

U.S. Navy

the green bank telescope and the nrqz
The Green Bank Telescope and the NRQZ

The National Radio Quiet Zone (NRQZ) wasestablished by the Federal Communications Commission (FCC) and by the Interdepartment Radio Advisory Committee (IRAC) in 1958 to minimize possible harmful interference to the National Radio Astronomy Observatory (NRAO) in Green Bank, WV and the radio receiving facilities for the United States Navy in Sugar Grove, WV. The NRQZ encloses a land area of approximately 13,000 square miles near the state border between Virginia and West Virginia.

the vla
The VLA

The VLA consists of 27 antennas arranged in a huge Y up to 36km (22 miles) across -- roughly one and a half times the size of Washington, DC.Pattern. Each antenna is 25 meters (81 feet) in diameter; their output is combined electronically to give the resolution of an antenna 36km (22 miles) across, with the sensitivity of a dish 130 meters (422 feet) in diameter.

The resolution of the VLA is set by the size of the array -- up to 36km (22 miles) across. At the highest observing frequency (43GHz) this gives a resolution of 0.04 arcseconds:, sufficient to see a golf ball held by a friend 150km (100 miles) away. The dishes can move on a track and this allows the telescope to become the radio equivalent of a zoom lens.

arecibo observatory
Arecibo Observatory

The huge "dish" is 305 m (1000 feet) in diameter, 167 feet deep, and covers an area of about twenty acres. The surface is made of almost 40,000 perforated aluminum panels, each measuring about 3 feet by 6 feet, supported by a network of steel cables strung across the underlying karst sinkhole. It is a spherical (not parabolic) reflector.

Suspended 450 feet above the reflector is the 900 ton platform. Similar in design to a bridge, it hangs in midair on eighteen cables, strung from three reinforced concrete towers. The combined volume of reinforced concrete in all three towers is 9,100 cubic yards. Each tower is back-guyed to ground anchors with seven 3.25 inch diameter steel bridge cables. Another system of cables runs from each corner of the platform to large concrete blocks under the reflector. They are attached to giant jacks which allow adjustment of each corner with millimeter precision.

investment in radio astronomy facilities 1990 present and planned
INVESTMENT IN RADIO ASTRONOMY FACILITIES 1990- Present and Planned

USA

GREEN BANK TELESCOPE (GBT) NRAO$ 85 M

ARECIBO (UPGRADE) NAIC $ 22 M

SUBMILLIMETER WAVELENGTH ARRAY (SWA)SAO $ 62 M

EVLA (Phase I) NRAO $ 50 M

ALMA (US Contrb.) NRAO $330 M

LARGE MILLIMETER TELESCOPE (LMT) U Mass $ 43 M

CARMA U. Calif- CALTECH $ 15 M

ALLEN TELESCOPE ARRAY (ATA) Berkeley-Private $ 25 M

SKA (Development) Consortium $ 1.5 M

Total $ 169 + 464.5 M = 633.5 M

Non-USA

ALMA EUROPE $330 M

LMT MEXICO $ 43 M

GMRT INDIA ~$ 50 M?

SARDINIA ITALY ~$60 M?