Andreas W. Neitzel
CV
Andreas in a hard hat in front of a Unit Telescope enclosure at Paranal, May 2024.

Field guide

What are ESO and the Very Large Telescope?

ESO is an intergovernmental observatory that builds and runs large telescopes in Chile, among them the Very Large Telescope at Paranal.

ESO's sites in Chile, and Paranal with the four Unit TelescopesLeft: Chile with ESO's sites at Paranal, Cerro Armazones, where the ELT is being built, and La Silla. Right: a rendered model of the Paranal summit seen from the west, with the four Unit Telescopes, UT2 open for the night, and the light ducts under the platform from each Unit Telescope to the Combined-Coudé Laboratory. Inset: UT2 with its enclosure removed, showing the telescope on its fork and the path of the light from the primary mirror to the secondary, to the Nasmyth B focus and down to the Coudé room.ESO SITES IN CHILEParanalVLTCerro ArmazonesELTLa SillaPARANALUT4UT3UT1Combined-Coudé LaboratoryUT2Nsecondary mirrorprimary mirrorCoudé roomUT2, ENCLOSURE REMOVEDCreator: Andreas W. Neitzel. © Andreas W. Neitzel. All rights reserved. https://andreaswneitzel.github.io

The European Southern Observatory (ESO) is an intergovernmental organisation that builds and runs telescopes in the Atacama Desert in Chile for its member states, Portugal among them. Its Very Large Telescope (VLT) at Paranal consists of four telescopes with mirrors 8.2 metres across. ESPRESSO, one of the instruments there, spreads a star's light into a detailed spectrum and measures tiny shifts in it, which show how fast the star's surface moves towards or away from us.

ESO was established in 1962 and has 16 member states; Portugal joined in 2001. Paranal Observatory is 2,635 metres above sea level, and the first VLT Unit Telescope began routine science on 1 April 1999. ESPRESSO, the Echelle SPectrograph for Rocky Exoplanet and Stable Spectroscopic Observations, saw first light in December 2017. With it, Campante and colleagues (2026) measured oscillations in the nearby K dwarf GJ 570 A with a peak amplitude of 2.57 ± 0.52 cm per second, against 16.0 cm per second for the Sun.

Where I come in

From 4 to 12 May 2024 I was at Paranal as a visiting astronomer for run 113.26FX.002, and on its six scheduled nights (6 to 12 May) I observed the K dwarf GJ 570 A with ESPRESSO in visitor mode, that is, on site. I did this on behalf of the principal investigator, Tiago L. Campante; the observing proposal was his. The data are in Campante et al. 2026, published in Astronomy and Astrophysics (doi:10.1051/0004-6361/202660350), where I am sixth of 24 authors.