Elle a de la chance

#ELODIE #noplp

Last updated 2 years ago

Γ‡a pue pour

#ELODIE #noplp

Last updated 2 years ago

Je pense qu’elle ne risque rien

#ELODIE #noplp

Last updated 2 years ago

Michele Garbarino · @micchega
127 followers · 625 posts · Server mastodon.lol

Since 2006, is replacing at the 1.93-m telescope and a major upgrade, , is planned for early 2023.

is able to reach a radial velocity precision down to 1m/s.

SOPHIE is also in a thermally controlled room. I'm working with this instrument since 2009 and I never had the opportunity to actually see it (only on this picture). I was able to enter the temperature-controlled room only once, to perform some test / measurements.
Maybe next year for ?

#SOPHIE #ELODIE #SOPHIERed

Last updated 2 years ago

All these optical elements can now be seen on the ground floor of the 1.93-m telescope at the (πŸ‡«πŸ‡· ). Here are a few pictures of I took for you.

#HauteProvence #observatory #ELODIE #astronomy #exoplanet

Last updated 2 years ago

All these optical elements can now be seen on the ground floor of the 1.93-m telescope at the (πŸ‡«πŸ‡· ). Here are a few pictures of I took for you.
.

#HauteProvence #observatory #ELODIE #astronomy #exoplanet

Last updated 2 years ago

is a cross-dispersion spectrograph, meaning that the stellar light is first dispersed by a grating and then cross-dispersed by a prism. This makes spectrum to appear like a ladder (echelle in πŸ‡«πŸ‡· ) and not a single line spectrum. We call these kind of optical design an echelle spectrograph (see picture).

- 48 & 49: the fibers
- 38: the grating
- 42: the prism.
- 47: the CCD cooled by liquid nitrogen to -100ΒΊC (-148Β°F).

Other optical elements are collimation mirrors.

#ELODIE

Last updated 2 years ago

The third instrumental was to use digital detectors (CCD) that started to be used in astronomy in the late 80's / early 90's. was developed in 1994 so this technology was pretty new in . CCDs offer much more stable and precise measurements. They also have many pixels allowing to record the entire visible spectrum at once (see picture). In comparison, was using a (1-px) photo-multiplicator to measure the stellar light.

#breakthrough #ELODIE #astronomy #CORAVEL

Last updated 2 years ago

The second instrumental for the development of was to install the spectrograph in a stable, temperature controlled room, to avoid any deformation of the opto-mechanical elements that lead to instrumental radial velocity variation, that we want to avoid.

The pictures below show , sitting on a marble table and covered to limit thermal changes in its environment.

#breakthrough #ELODIE

Last updated 2 years ago

However, in the mid-1990's when was developed, very few people actually managed to feed stellar light through fibers. It indeed requires a very precise optical alignment (with micro-lensing at the fiber entrance) and most attempt at the time led to low throughput. But AndrΓ© managed to do it, which was really an instrumental at that time.

We can see in this picture the same orange fibers entering the optical parts of the spectrograph.

#ELODIE #breakthrough

Last updated 2 years ago

To improve the radial velocity precision, had to be a much more stable instrument, in a temperature- and pressure-controlled environment which was not compatible with the dome.

So, AndrΓ© Baranne (a french astronomer at Marseille Observatory who also built in 1977) suggested to use optical to feed the stellar light from the to the instrument. We can see these fibers in orange in this picture of the bonnette, mounted on the 1.93-m telescope at .

#ELODIE #CORAVEL #fibers #telescope #HauteProvence

Last updated 2 years ago

The jump in precision between the (300m/s) and the (10m/s) spectrographs was due to several achievements.

CORAVEL was mounted directly on the back of the swiss telescopes at either the or observatories. In such case, the instrument's and components are deformed by , and the position of the telescope. Such deformation was a clear limitation to the radial velocity precision.

#CORAVEL #ELODIE #HauteProvence #LaSilla #optical #mechanical #temperature #humidity

Last updated 2 years ago

is a that was able to measure the radial velocity of via the effect with a precision down to about 10m/s.

It is actually the successor of the spectrograph with which Michel Mayor & Antoine Duquennoy studied the population of binary stars in the neighborhood. had a precision down to about 300m/s which is not enough to discover (most) exoplanets.

is thus a super coravel.

#ELODIE #spectrograph #stars #Doppler #CORAVEL #solar

Last updated 2 years ago

In 1995, the swiss Michel Mayor and Didier Queloz discovered the first orbiting a -like : 51 Peg b. For that, they received the 2019 Physics' Prize.

This discovery opened a new field of research in . It was based on done with the 1.93m at (πŸ‡«πŸ‡· ) with the instrument .

Below ‡️ is a presenting this instrument who allowed the discovery of 51Peg b.

#astronomers #exoplanet #sun #star #nobel #astronomy #observations #telescope #HauteProvence #observatory #ELODIE #thread #astrophysics #science

Last updated 2 years ago