Not a great night for astronomy with lots of thin cloud passing, but we could still observe. I went out and did some photography in the small hours of Christmas morning, and the Moon briefly shone through the shutters of UT4 as it set behind the cloud.
Long after sunset but still before the sky was properly dark, Orion was setting over the telescopes. The orange glow on the horizon comes from the Escondida copper mine 90 miles away.
Paranal does the majority of its work in service mode, where we, the observatory staff, carry out observations that have been requested and designed by other astronomers. This has the advantage that if they need certain weather conditions, then we simply wait until we have conditions as good or better than needed and take the observations then. But for the astronomers to come and carry out their own observations also has its advantages - they can see much better how the observatory works, and make sure the data is exactly as they want it. But though the weather is good here at least 90 per cent of the time, there's still a chance that a visitor will get no data at all. That happened tonight, and it was sadder than usual because it was Christmas night. People had travelled thousands of miles to be away from friends and families, in the hope of better understanding some of the mysteries of the universe in compensation, but it was cloudy for most of the night and we couldn't do any observing at all.
The VLT is the Very Large Telescope. That's the name given to the whole facility that consists of our four telescopes each with a mirror 8.2m across. Here, you see two of them, Melipal, which I work as a support astronomer for, and Yepun, which has a cool laser. In between them is the VST, which only has a 2.5m mirror, but VST is disappointingly not actually an acronym for Very Small Telescope, but instead means VLT Survey Telescope. It is used for large surveys, such as the VPHAS+, which I'm involved in and which is taking images of the Milky Way in the light emitted by hydrogen gas. VPHAS+ is a double nested acronym - it's the VST Photometric Hα Survey, so that would actually be the Very Large Telescope Survey Telescope Photometric Hα Survey.