150.5 - Controlling the ELT

Guest: Thomas Pfrommer Host: Markus Voelter Shownoter: Pascal Becker

Six years ago, in episode 150 (omegataupodcast.net/150-the-european-extremely…), Jochen Liske of ESO (eso.org) told us about the Extremely Large Telescope (de.wikipedia.org/wiki/Extremely_Large_Telescope) that is currently being built in Chile. This episode is a continuation (which is why this is a kind of bonus episode labelled as 150.5) in which Thomas Pfrommer tells us about how to control the optical path of this monster telescope: the 39 meter, 798-segment main mirror, plus the four additional mirrors involved in bringing the light to a stable and sharp focus. I recorded this episode mainly to fill in some “gaps” I needed for the book (onceyoustartasking) chapter on telescopes.

Here is the paper I read, which triggered this episode: MELT – An optomechanical emulation testbench for ELT wavefront control and phasing strategy (symetrie.fr/wp-content/uploads/2018/07/Publica…). You should read it before you listen. Just kidding (sort of :-)).

E-ELT Telescope Setup
00:04:09
Ligth's five-mirror Journey through the E-ELT (youtube.com/watch?v=aqfLGrpOjjY) | 3 Mirros Design (en.wikipedia.org/wiki/Three-mirror_anastigmat) | en.wikipedia.org/wiki/Anastigmat | TMT (Thirty Meter Telescope) Hawaii (en.wikipedia.org/wiki/Thirty_Meter_Telescope) | GTC (Gran Telescopio Canarias) (en.wikipedia.org/wiki/Gran_Telescopio_Canarias) | en.wikipedia.org/wiki/Wavefront | Adaptive Optics (en.wikipedia.org/wiki/Adaptive_optics) | Active Optics (en.wikipedia.org/wiki/Active_optics) | LBT (Large Binocular Telescope) (en.wikipedia.org/wiki/Large_Binocular_Telescope) | VLT (Very Large Telescope) (en.wikipedia.org/wiki/Very_Large_Telescope) | Lookup Table (en.wikipedia.org/wiki/Lookup_table) | Open-Loop Control (en.wikipedia.org/wiki/Open-loop_controller) (omega tau 111 - Optical Astronomy and the Large Binocular Telescope (omegataupodcast.net/111-optical-astronomy-and-…))

Interaction between control and adaptive optics
00:47:08
Atmospheric distortion (spaceguard.rm.iasf.cnr.it/tumblingstone/dictio…)

Mini E-ELT
00:52:50