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Results for “Ground-based astronomy”

Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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At least 19 records
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NASA NTRS1974

MSFC Skylab ground-based astronomy program

The Skylab Ground-Based Astronomy Program (SGAP) was conducted to enhance the data base of solar physics obtained during the Apollo Telescope Mount (ATM) mission flown in conjunction with the Skylab orbital station. Leading solar physicists from various observatories obtained data from the ground at the same time that orbital data were being acquired by ATM. The acquisition of corollary solar data from the ground simultaneously with the ATM orbital observations helped to provide a broader basis for understanding solar physics by increasing spectral coverage and by the use of additional sophisticated instruments of various types. This report briefly describes the individual tasks and the associated instrumentation selected for this ground-based program and contains as appendices, the final reports from the Principal Investigators.

Duncan, B. J.↗
NASA NTRS1965

Ground-based bistatic radar astronomy.

Ground-based bistatic radar astronomy technique using distantly spaced receiver and transmitter in trial measurement of lunar angular size

RADIO ECHO OBSERVATION↗
NASA NTRS1976

Telescopes and space exploration

The necessity for different types of telescopes for astronomical investigations is discussed. Major findings in modern astronomy by ground-based and spaceborne telescopes are presented. Observations of the Crab Nebula, solar flares, interstellar gas, and the Black Hole are described. The theory of the oscillating universe is explored. Operating and planned telescopes are described.

Brandt, J. C.↗
NASA NTRS1973

Thunderstorms and ground-based radio noise as observed by radio astronomy Explorer 1

Radio Astronomy Explorer (RAE) data were analyzed to determine the frequency dependence of HF terrestrial radio noise power. RAE observations of individual thunderstorms, mid-ocean areas, and specific geographic regions for which concommitant ground based measurements are available indicate that noise power is a monotonically decreasing function of frequency which conforms to expectations over the geographic locations and time periods investigated. In all cases investigated, active thunderstorm regions emit slightly higher power as contrasted to RAE observations of the region during meteorologically quiet periods. Noise levels are some 15 db higher than predicted values over mid-ocean, while in locations where ground based measurements are available a maximum deviation of 5 db occurs. Worldwide contour mapping of the noise power at 6000 km for five individual months and four observing frequencies, examples of which are given, indicate high noise levels over continental land masses with corresponding lower levels over ocean regions.

Caruso, J. A.↗
NASA NTRS1977

Very high-energy gamma ray astronomy

Recent results in ground-based very high-energy (less than 10 to the eleventh power eV) gamma-ray astronomy are reviewed. The various modes of the atmospheric Cerenkov technique are described, and the importance of cosmic ray rejection methods is stressed. The positive detections (at approximately less than 10 to the 12th power eV) of the Crab pulsar that suggest a very flat spectrum and time-variable pulse phase are discussed. Observations of other pulsars (particularly Vela) suggest that these features may be general. The steady flux upper limits for the Crab Nebula are thus reconsidered, and a new value of the implied (Compton-synchrotron) magnetic field in the Nebula is reported. Evidence that a 4.8-hour modulated effect was detected at E sub gamma is less than 10 to the 12th power eV from Cyg X-3 is strengthened in that the exact period originally proposed agrees well with a recent determination of the X-ray period. The southern sky observations are reviewed, and the significance of the detection of an active galaxy (NGC 5128) is considered for source models and future observations.

Grindlay, J. E.↗
NASA NTRS1971

The Gum nebula and related problems

Papers were presented in conference sessions on the Gum nebula, the Vela X remnant, the hot stars gamma Velorum and zeta Puppis, the B associations in the Vela-Puppis complex, and pulsars. Ground-based optical and radio astronomy; rocket and satellite observations in the radio, visible, ultraviolet, and X-ray regions; and theoretical problems in the physical state of the interstellar medium, stellar evolution, and runaway star dynamics were considered.

Maran, S. P.↗
NASA NTRS1993

The Telecommunications and Data Acquisition Report

This quarterly publication provides archival reports on developments in programs managed by JPL's Office of Telecommunications and Data Acquisition (TDA). In space communications, radio navigation, radio science, and ground-based radio and radar astronomy, it reports on activities of the Deep Space Network (DSN) in planning, supporting research and technology, implementation, and operations. Also included are standards activity at JPL for space data and information systems and reimbursable DSN work performed for other space agencies through NASA. The preceding work is all performed for NASA's Office of Space Communications (OSC). The TDA Office also performs work funded by another NASA program office through and with the cooperation of OSC. This is the Orbital Debris Radar Program with tile Office of Space Systems Development. The TDA Office is directly involved in several tasks that directly support the Office of Space Science (OSS), with OSC funding DSN operational support. In radio science, The TDA Progress Report describes the spacecraft radio science program conducted using tile DSN. For the High-Resolution Microwave Survey (HRMS), the report covers implementation and operations for searching the microwave spectrum. In solar system radar, it reports on the uses of the Goldstone Solar System Radar for scientific exploration of the planets, their rings and satellites, asteroids, and comets. In radio astronomy, the areas off support include spectroscopy, very long baseline interferometry, and astrometry.

Edward C Posner↗
NASA NTRS1972

Interplanetary cosmic dust flux

Pioneer 8 and 9 measured cosmic dust flux rate data are in agreement with astronomy theory, zodiacal light measurements, and ground-based observations, but differ markedly from the high flux rates deduced from earlier in situ measurements. As many as seven orders-of-magnitude separate the small particle end of the high and low flux curves. It was concluded that the data from the multicoincidence cosmic dust sensors have not only measured very low flux for micrometeorites, which is in keeping with astronomy theory, but have also shown how a high flux theory may be based on faulty data.

Berg, O. E.↗
NASA NTRS1974

Infrared astronomy and the Shuttle

The infrared spectral range extends approximately from 1 micron to 1000 microns. Observations in infrared astronomy are made with the aid of ground-based telescopes and telescopes flown in aircraft, balloons, or rockets. Advantages and drawbacks of infrared studies conducted by different approaches are discussed. Infrared astronomers are looking forward to observations made from orbiting spacecraft. Present plans call for placing a large telescope aboard the Space Shuttle Orbiter for short missions lasting from seven days to three weeks several times a year. However, the occurrence of a pollution of the spacecraft environment by dust particles and gases coming from the spacecraft might present a problem for the observations. Possible approaches for solving this problem are discussed.

Harwit, M.↗
NASA NTRS1970

System automatically tunes hydrogen masers

Automatic tuning system permits frequency synchronization between two hydrogen masers. System matches spaceborne clock performance with that of ground-based clock to test red shift theory. This system, used in conjunction with radio astronomy for long-baseline interferometer experiments, serves as a tool for investigation of distant universe phenomena.

Levine, M. W.↗
NASA NTRS1974

Survey of the galactic background radiation at 3.93 and 6.55 MHz

A survey of the galactic background radiation at 3.93 and 6.55 MHz is presented for the region between declinations of -60 and +60 deg. The observations were obtained with the 229-m traveling-wave V-antenna on the Radio Astronomy Explorer-1 satellite with an angular resolution of the order of one steradian. The results are consistent with the findings of high-resolution ground-based surveys at low frequencies and provide a first step in extending such observations over the whole sky.

Alexander, J. K.↗
NASA NTRS1976

Efficient computer algorithms for infrared astronomy data processing

Data processing techniques to be studied for use in infrared astronomy data analysis systems are outlined. Only data from space based telescope systems operating as survey instruments are considered. Resulting algorithms, and in some cases specific software, will be applicable for use with the infrared astronomy satellite (IRAS) and the shuttle infrared telescope facility (SIRTF). Operational tests made during the investigation use data from the celestial mapping program (CMP). The overall task differs from that involved in ground-based infrared telescope data reduction.

Pelzmann, R. F., Jr.↗
NASA NTRS1978

Future prospects of infrared observations of active nuclei

Future developments in infrared observations are briefly discussed. The prospects for large advances in ground-based broad-band observations probably lie in increased availability of dedicated telescopes and observing time. Several specific areas of potential advancement are described. The plans for the utilization of space for infrared astronomy call for an unbiased all-sky survey in the wavelengths 8-120 microns followed by complementary missions using a cooled moderate sized telescope and a large uncooled telescope.

Neugebauer, G.↗
NASA NTRS1974

Astronomy satellites in the U.S. program

The Orbiting Astronomical Observatory (OAO) series demonstrated that necessary thermal control systems and high pointing stability are feasible on astronomical satellites. A geosynchronous International Ultraviolet Explorer (IUE) is being planned by the US, UK, and ESRO for stellar spectroscopy. High Energy Astronomy Observatories, HEAO-A B, and C, will concentrate on stellar X-ray objects, cosmic ray physics, and gamma ray astronomy. A Shuttle-compatible Solar Maximum Mission (SMM) is planned for studying solar flares and flare related phenomena during the next solar maximum. Now in the instrumentation definition stage is the Large Space Telescope (LST), to provide higher resolution and sensitivity, larger wavelength range (from ultraviolet to far infrared), and higher time resolution than ground-based telescopes.

Aucremanne, M. J.↗
NASA NTRS1978

The Space Telescope - A giant step in astronomy

The astronomer's capacity for observation will be tremendously enhanced by NASA's Space Telescope, a multipurpose optical telescope in earth orbit which will enable man to gaze seven times farther into space than has now been done, possibly to the outer edges of the universe. The Space Telescope is to be placed in orbit in 1983 by the NASA Space Shuttle. The turbulence of the earth atmosphere imposes practical limitations in all but a very few types of astronomical observations conducted on the surface of the earth. The Space Telescope, high above the hazy and turbulent atmosphere, will enable scientists to see the heavens clearly for the first time. The Space Telescope is a superb system that fully exploits the advantages of space observations and will dramatically extend the astronomer's capabilities beyond ground-based telescopes.

Odell, C. R.↗