Holographic Measurement and Improvement of the Green Bank Telescope Surface

  title={Holographic Measurement and Improvement of the Green Bank Telescope Surface},
  author={Todd R. Hunter and Frederic R. Schwab and Steven White and John M. Ford and Frank D. Ghigo and Ronald J. Maddalena and Brian S. Mason and John D. Nelson and Richard M. Prestage and Jason Ray and Paul A. Ries and Robert Simon and Sivasankaran Srikanth and Peter Whiteis},
  journal={Publications of the Astronomical Society of the Pacific},
  pages={1087 - 1099}
We describe the successful design, implementation, and operation of a 12 GHz holography system installed on the Robert C. Byrd Green Bank Telescope (GBT). We have used a geostationary satellite beacon to construct high-resolution holographic images of the telescope mirror surface irregularities. These images have allowed us to infer and apply improved position offsets for the 2209 actuators which control the active surface of the primary mirror, thereby achieving a dramatic reduction in the… 
Correcting Gravitational Deformation at the Tianma Radio Telescope
The primary reflector of the Tianma Radio Telescope (TMRT) distorts due to gravity, which dramatically reduces the aperture efficiency of high-frequency observations. A technique known as
The laser antenna surface scanning instrument
To carry out astronomical observations in the molecule rich 3 mm window the Green Bank Telescope (GBT) compensates for gravitational and weather induced deformations of its primary reflector.
Tied-array holography with LOFAR
Context. A radio interferometer uses time delays to maximize its response to radiation coming from a particular direction. These time delays compensate for differences in the time of arrival of the
Evaluating a strategy for measuring deformations of the primary reflector of the Green Bank telescope using a terrestrial laser scanner
Astronomical observations in the molecule rich 3‐mm window using large reflector antennas provide a unique view of the Universe. To efficiently carry out these observations gravitational and thermal
Surface accuracy and pointing error prediction of a 32 m diameter class radio astronomy telescope
Surface Accuracy and Pointing Error Prediction of a 32 m Diameter Class Radio Astronomy Telescope S. Azankpo Department of Mechanical and Mechatronics Engineering, University of Stellenbosch, Private
Performance Analysis of Paraboloidal Reflector Antennas in Radio Telescopes
In this paper, we present an analysis on the performance of the three most commonly used paraboloidal reflector antennas in radio telescopes - i.e. the prime focus, Cassegrain, and Gregorian
Analysis of Reflector Antennas in Radio Telescopes
The results obtained from the physical optics simulation show that the radiation characteristics of both Cassegrain and Gregorian antennas are similar, and the offset designs exhibit the best performance, followed by the on-axis, and, finally, the off-axis designs.
Measuring and analyzing thermal deformations of the primary reflector of the Tianma radio telescope
The primary reflector of the Tianma Radio Telescope (TMRT) distorts due to the varying thermal conditions, which dramatically reduces the aperture efficiency of Q-band observations. To evaluate and
Antennas and Receivers in Radio Interferometry
The primary antenna elements and receivers are two of the most important components in a synthesis telescope. Together they are responsible for locking onto an astronomical source in both direction
GBT Memo # 301 The GBT Gain Curve at High Frequency
Recent measurements at Q-band (43 GHz) have verified the improved performance of the GBT provided by the updated gravity model that was deployed in the fall of 2014. The measured gain curve is


Out-of-focus holography at the Green Bank Telescope
Mullard Radio Astronomy Observatory, Cavendish Laboratory, Cambridge CB3 0HE, UKthe date of receipt and acceptance should be inserted laterAbstract. We describe phase-retrieval holography
Microwave holography of large reflector antennas--Simulation algorithms
Different simulation models are investigated with emphasis given to a model based on the vector diffraction analysis of a curved reflector with displaced panels, which is used to reconstruct the location and amount of displacement of the surface panels by employing a fast Fourier transform (FFT)/iterative procedure.
Green Bank Telescope active surface system
  • R. Lacasse
  • Physics
    Astronomical Telescopes and Instrumentation
  • 1998
During the design phase of the Green Bank Telescope (GBT), various means of providing an accurate surface on a large aperture paraboloid, were considered. Automated jacks supporting the primary
Near-Field Radio Holography of Large Reflector Antennas
We summarize the mathematical foundation of the holographic method of measuring the reflector profile of an antenna or radio telescope. In particular, we treat the case where the signal source is
Microwave holographic metrology of large reflector antennas
A microwave holographic technique for the determination of amplitude and phase of the principal and cross-polarized aperture fields of large reflector antennas is described. The hologram formation
Measurement of antenna surfaces from in- and out-of-focus beam maps using astronomical sources
We present a technique for the accurate estimation of large-scale errors in an antenna surface using astronomical sources and detectors. The technique requires several out-of-focus images of a
The most X-ray luminous cluster known, RXJ1347−1145 (z = 0.45), has been the object of extensive study across the electromagnetic spectrum. We have imaged the Sunyaev–Zel'dovich effect (SZE) at 90
We present resolved images of four massive clusters of galaxies through the Sunyaev–Zel'dovich effect (SZE). These measurements, made at 90 GHz with the MUSTANG receiver on the Green Bank Telescope
Repetitive radio reflector surface deformations
Holography measurements of radio reflector surfaces have revealed temperature induced panel buckling. This buckling is a typical example of repetitive deformations which are not covered by the theory