Atmospheric seeing and its amelioration

2015 ◽  
pp. 53-90
Author(s):  
David F. Buscher ◽  
Malcolm Longair
Keyword(s):  
Atmospheric Seeing

scholarly journals A New Michelson Stellar Interferometer

1977 ◽  
Vol 33 ◽  
pp. 35-37
Author(s):  
R. Q. Twiss ◽  
W. J. Tango
Keyword(s):  
Quantitative Measurement ◽  
Binary Star ◽  
Resolving Power ◽  
Fringe Visibility ◽  
Stellar Interferometer ◽  
Royal Observatory ◽  
Atmospheric Seeing

AbstractA new 1.87 m fixed-baseline interferometer designed for binary star observation is now in operation at the Italian outstation of the Royal Observatory Edinburgh. It has a theoretical resolving power of 0.015 arcsee and a limiting B magnitude of 6.5. Atmospheric seeing is dynamically corrected, allowing a quantitative measurement of fringe visibility.

scholarly journals Infrared Speckle Interferometry: A Sensitive Technique for Physical Measurements of Unseen Companions to Nearby Stars

1986 ◽  
Vol 109 ◽  
pp. 309-319
Author(s):  
D. W. McCarthy
Keyword(s):  
Main Sequence ◽  
Position Angle ◽  
Speckle Interferometry ◽  
Resolving Power ◽  
Detector Arrays ◽  
Physical Measurements ◽  
Nearby Stars ◽  
Absolute Magnitudes ◽  
Large Telescopes ◽  
Atmospheric Seeing

Infrared speckle interferometry combines the full resolving power of large telescopes with high photometric sensitivity over the wavelength range 2.2 to 12 microns. Despite improved atmospheric seeing at these wavelengths, seeing fluctuations limit measurement precision. Astrometric companions have been detected with angular separations ≥0.1 arcsec and magnitude differences ≤3.7 mag. Results illustrate seeing limitations and show how the usual position angle ambiguity can be overcome. These measurements yield masses and absolute magnitudes for calibrating the lower main sequence. In some cases, orbital motion is detected. A method of “shift-and-add” enables detection of substellar (0.04 to 0.08 M⊙) companions. Future improvements involving detector arrays and seeing monitors are discussed.

scholarly journals NAOMI: the adaptive optics system of the Auxiliary Telescopes of the VLTI

2019 ◽  
Vol 629 ◽  
pp. A41 ◽  
Author(s):  
J. Woillez ◽  
J. A. Abad ◽  
R. Abuter ◽  
E. Aller Carpentier ◽  
J. Alonso ◽  
...  
Keyword(s):  
Adaptive Optics ◽  
Single Mode ◽  
Large Telescope ◽  
Wavefront Correction ◽  
Design Performance ◽  
Very Large Telescope ◽  
Fringe Tracking ◽  
Adaptive Optics System ◽  
Atmospheric Seeing

Context. The tip-tilt stabilisation system of the 1.8 m Auxiliary Telescopes of the Very Large Telescope Interferometer was never dimensioned for robust fringe tracking, except when atmospheric seeing conditions are excellent. Aims. Increasing the level of wavefront correction at the telescopes is expected to improve the coupling into the single-mode fibres of the instruments, and enable robust fringe tracking even in degraded conditions. Methods. We deployed a new adaptive optics module for interferometry (NAOMI) on the Auxiliary Telescopes. Results. We present its design, performance, and effect on the observations that are carried out with the interferometric instruments.

The Four-Laser Guide Star Facility: Design considerations and system implementation

2014 ◽  
Vol 3 (3) ◽  
Author(s):  
Domenico Bonaccini Calia ◽  
Wolfgang Hackenberg ◽  
Ronald Holzlöhner ◽  
Steffan Lewis ◽  
Thomas Pfrommer
Keyword(s):  
Adaptive Optics ◽  
Technical Solution ◽  
Laser Guide Star ◽  
Laser Guide Stars ◽  
Very Large Telescope ◽  
Guide Star ◽  
Laser Guide ◽  
Sodium Laser ◽  
Optical Telescopes ◽  
Atmospheric Seeing

AbstractGround-based optical telescopes, in particular large ones, require adaptive optics to overcome the atmospheric seeing limit due to turbulence. Correcting the distorted wavefront necessitates bright stars in the field of view. The sky coverage can be greatly increased by using artificial sodium laser guide stars in addition to natural guide stars. We describe the underlying physics and technical considerations relevant to such systems before discussing the design of the four-laser guide star facility (4LGSF) which is currently under development for the ESO Very Large Telescope (VLT) on Cerro Paranal, Chile. The focus is upon the justification of the requirements and their technical solution.

scholarly journals LOW FREQUENCY SEEING AND SOLAR DIAMETER MEASUREMENTS

2013 ◽  
Vol 23 ◽  
pp. 437-442
Author(s):  
COSTANTINO SIGISMONDI ◽  
XIAOFAN WANG
Keyword(s):  
Low Frequency ◽  
Image Motion ◽  
The Sun ◽  
Solar Diameter ◽  
Drift Scan ◽  
Half Degree ◽  
Atmospheric Seeing

The action of the atmospheric seeing is blurring, image stretching and image motion. This happens even to the image of the Sun which is more than half degree wide. Low frequency seeing components affect the solar diameter values measured either through the drift-scan or the heliometer methods. We present evidences of image motion and stretching down to 0.001 Hz.

Atmospheric seeing measurements in the near-infrared

1994 ◽  
Author(s):  
Colin M. Humphries ◽  
Eli Atad-Ettedgui ◽  
John W. Harris ◽  
A. M. Smillie ◽  
Colin Aspin ◽  
...  
Keyword(s):  
Near Infrared ◽  
Atmospheric Seeing
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