Date: 16/02/2018 22:49:17
From: Tau.Neutrino
ID: 1189281
Subject: ESO's VLT Espresso

Witness The Power Of A Fully Operational ESPRESSO Instrument. Four Telescopes Acting As One

It’s been 20 years since the first of the four Unit Telescopes that comprise the ESO’s Very Large Telescope (VLT) saw first light. Since the year 2000 all four of them have been in operation. One of the original goals of the VLT was to have all four of the ‘scopes work in combination, and that has now been achieved.

The instrument that combines the light from all four of the VLT ‘scopes is called ESPRESSO, which stands for Echelle SPectrograph for Rocky Exoplanet and Stable Spectroscopic Observations. ESPRESSO captures the light from each of the 8.2 meter mirrors in the four Unit Telescopes of the VLT. That combination makes ESPRESSO, in effect, the largest optical telescope in the world.

more…

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Date: 16/02/2018 22:53:07
From: Tau.Neutrino
ID: 1189284
Subject: re: ESO's VLT Espresso

Wow, imagine if all optical telescopes could act as one.

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Date: 17/02/2018 07:57:08
From: mollwollfumble
ID: 1189312
Subject: re: ESO's VLT Espresso

Tau.Neutrino said:


Witness The Power Of A Fully Operational ESPRESSO Instrument. Four Telescopes Acting As One

It’s been 20 years since the first of the four Unit Telescopes that comprise the ESO’s Very Large Telescope (VLT) saw first light. Since the year 2000 all four of them have been in operation. One of the original goals of the VLT was to have all four of the ‘scopes work in combination, and that has now been achieved.

The instrument that combines the light from all four of the VLT ‘scopes is called ESPRESSO, which stands for Echelle SPectrograph for Rocky Exoplanet and Stable Spectroscopic Observations. ESPRESSO captures the light from each of the 8.2 meter mirrors in the four Unit Telescopes of the VLT. That combination makes ESPRESSO, in effect, the largest optical telescope in the world.

more…

Wow, imagine if all optical telescopes could act as one.

Aagh. I thought that the four telescopes had already been used as one. I’ve been telling people how powerful this is since about the year 2000. Now I find out that it’s never been done. Apologies to all.

All optical telescopes acting as one would be have fantastic resolution. Would they all have to be tuned to the same wavelengh or not?

I’m trying to figure out why it’s taken so long to put all four together. One possibility is that all four together gives high resolution of very faint objects. In the past, the telescope has either done high resolution of bright objects (eg. Planet orbiting star) or average resolution of very faint objects (eg. Distant galaxy clusters).

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Date: 17/02/2018 08:17:12
From: mollwollfumble
ID: 1189314
Subject: re: ESO's VLT Espresso

Tau.Neutrino said:


Wow, imagine if all optical telescopes could act as one.

It’s been done with radio telescopes.

https://www.sciencemag.org/news/1997/02/larger-earth-radio-telescope

https://www.newscientist.com/article/dn20705-space-telescope-to-create-radio-eye-larger-than-earth/

The next step up from radio telescopes would be infrared. Most large optical telescopes have infrared capability. With current technology I can’t see any reason why large infrared telescopes couldn’t be linked into a giant interferometer. There are perhaps as many as ten infrared telescopes in Mauna Kea Observatory that could be linked up for starters. Or perhaps start by linking four large infrared observatories in South America: Cerro Tololo, VLT, La Silla and Las Campanas. Before later adding the Canary Islands.

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Date: 17/02/2018 08:36:48
From: mollwollfumble
ID: 1189315
Subject: re: ESO's VLT Espresso

“Detection of Earth twins in the Habitable Zone of solar-type stars.
The search for extra-solar earth-like planets which at least in principle could sustain life similar to that on our planet catches the imagination of scientists as well as that of the general public. The required accuracy for radial velocity searches to detect rocky planets in the habitable zone of 10 cm/s is in reach with the proposed HARPS-like spectrograph ESPRESSO for the VLT.”

There are plans for an optical interferometer with 10 times the resolution of ESPRESSO. Construction began in 2017. First light is planned for 2024. This is the European Extremely Large Telescope, E-ELT. The interferometer planned for it is called CODEX. More on CODEX at http://www.iac.es/proyecto/codex/pages/science-show-cases/earth-twins.php

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Date: 17/02/2018 08:41:18
From: mollwollfumble
ID: 1189317
Subject: re: ESO's VLT Espresso

What is ESPRESSO actually looking at?

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Date: 18/02/2018 14:44:43
From: mollwollfumble
ID: 1189781
Subject: re: ESO's VLT Espresso

mollwollfumble said:


What is ESPRESSO actually looking at?

I think I understand now. https://www.eso.org/public/news/eso1739/

ESPRESSO doesn’t take photographs, it measures velocities by zooming in on spectral line shifts.

“The Echelle SPectrograph for Rocky Exoplanet and Stable Spectroscopic Observations (ESPRESSO) has successfully made its first observations. ESPRESSO aims to achieve a precision in measuring the doppler shift due to changes in the speed of a star of just a few centimetres per second. This radial velocity method works because a planet’s gravitational pull influences its host star, causing it to “wobble” slightly. The less massive the planet, the smaller the wobble, and so for rocky and possibly life-bearing exoplanets to be detected, an instrument with very high precision is required. With this method, ESPRESSO will be able to detect some of the lightest planets ever found.”

Darn. I wanted it to take pretty pictures.

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