Solution Note
Author: Dr Andrew Dennis
Published: 01 Nov 2018 · Last updated: 26 Jan 2024
Tags: wavefront-sensors-app
As previously mentioned in Introduction to Astronomical Adaptive Optics, the Adaptive optic approach is a powerful tool for minimising the distortions caused by Atmospheric turbulence.
The Shack-Hartmann based Wavefront sensor approach can be seen at The Center for High Angular Resolution Astronomy (CHARA) Array, [2, 3] at the Mount Wilson Observatory. See Figure 1 & 2. The Chara Array is a IR and Near Infrared telescope system comprising of 6 optically connected telescopes, each fitted with an EMCCD (Andor iXon Ultra) based AO system which operates at 1000 frames per second (set up using a 90 x 90 pixel ROI).
Figure 1. Shack Hartmann Adaptive Optic setup at the Chara Array [4]
And alternative AO implementations can be found at The Large Binocular Telescope which utilises a Laser based guide Star, adaptive secondary mirror with 672 actuators and Andor Zyla sCMOS camera operating at 1 kHz (200 x 200 Pixels). [5,6]
The Raven AO system utilises 5 EMCCD cameras and used multiple objects in a field of view to perform Multi-object correction over a very large image plane.[8,9]
Table 1 Shows a broad range of Adaptive Optic systems and the telescopes where they are based.
Figure 2. Top left: short exposure (1 ms) PSF of GLIESE 777. Top right: long exposure (5 s) PSF of GLIESE 777. Bottom: radial profile of both short (dashed line) and long (blue continuous line) exposure PSFs. [7]
| Table 1, A list of Innovative Adaptive Optic systems. | |||
| 1 | Chara Array | Mt Wilson Observatory, CA | iXon 897 EMCCD |
| 2 | Large Binocular Telescope | Mt Graham International Observatory, AZ | Zyla sCMOS |
| 3 | Multi-Object Adaptive Optics (MOAO) | Subaru Telescope, Hawaii | 5 x Zyla |
| 4 | The portable adaptive optics System | Various | iXon 897 EMCCD |
| 5 | The Subaru Coronagraphic Extreme Adaptive Optics (SCExAO) instrument - VAMPIRES | Subaru Telescope, Hawaii | iXon 897 EMCCD |
| 6 | Robo AO | Palomar Observatory, CA | iXon 888 EMCCD |
| 7 | Fastcam | William Herschel Telescope, Canary Islands, Spain | iXon 897 EMCCD |
| 8 | Anglo Australian Telescope AO | Siding Spring Observatory, Australia | Zyla sCMOS |
| 9 | Canary Moao | William Herschel Telescope, Canary Islands, Spain | iXon EMCCD |
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