I cannot visit @esoastronomy HQ without photographing and posting about this video game box.
It is not just a bit of astronomy themed retro box art, there is an actual retro game to go with it too. It was written for the Atari 2600 but can also be played online: https://pietrow.net/atari/astronomer/
While at @esoastronomy HQ I also had to snap some photos of this impressive model of the ELT telescope. Soon the real thing will be looking like this. Note the toy cars for scale.
Elsewhere in the @esoastronomy building is this, a prototype primary mirror segment for the ELT telescope. Eventually the mirror will be assembled from 798 segments just like this one, but shinier and with fewer signatures.
Underneath is a prototype version of the mirror segment support structure and actuators, required to ensure that all the mirror segments remain perfectly aligned with each other.
In the @esoastronomy technical building is the integration hall, where there is more hardware related to the ELT telescope.
In the corner there is a prototype section of ELT primary mirror support structure with 7 aluminium dummy mirror segments on it.
The blue structure is the ELT Phasing & Diagnostic System (PDS), currently under construction. This instrument will be installed on the telescope to measure the shape of the primary mirror, allowing the positions of the 798 mirror segments to be adjusted so that they are perfectly aligned and can act as a single 39 metre diameter mirror.
It is expected that the PDS will be used roughly once a week to tune the primary mirror. Between tune ups the edge sensors between the mirror segments will be used to maintain the mirror's shape.
Returning to the models of @esoastronomy, I have to applaud whoever built this amazing Lego model of Paranal Observatory.
They included the 4 Unit Telescopes, 4 Auxiliary Telescopes, the VLT Survey Telescope, the control building, the VLTI Lab, and even a representation of the VLTI delay lines and beam combiner lab below the Platform. Unit Telescope 4, the eventual home of the MAVIS instrument, even has its four laser beams.
A final thing spotted at @esoastronomy: A̶l̶l̶e̶n̶ Ally keys.
I have a couple of sets of colourful Wera Allen keys and the distinct colours are helpful for keeping track of which is which when you're using several of them, but they are not as rainbow coloured as these Swiss Tools ones and therefore not as good. 🌈
Oh, I see that instructions and brick lists for Lego ELT and VLT models designed by Frans Snik can be found here: https://www.eso.org/public/australia/announcements/ann16013/?lang
Anthony Horton
Jure Repinc 
cybervegan