Now posted by the European Southern Observatory (ESO):
https://www.eso.org/public/announcements/ann25011/
16 Dec 2025, New SOXS instrument ready to observe fleeting cosmic events
The SOXS instrument– Son of X-Shooter- has been installed on the La Silla telescope in Chile, and has taken test observations. Why is this blog-worthy? The point of SOXS is to be a single, multi-purpose, multi-category instrument for follow-up on, oh… pretty much anything. After a Solar System object is discovered (say, Vera Rubin, anyone?) it needs follow-up observations, at minimum to nail down its orbit (or trajectory, for interstellar objects), and at most to gauge its threat to Earth, via size and composition studies. But our search telescopes have been tightly optimized, and don’t do so well at follow-up.
Vera Rubin itself has kept this in mind from the beginning, and has been designed to chase down the same target every 2-4 days (pending weather, downtime, etc.). In that 2-4 day interval, it may have switched filters to one of its other five. Taking data on an object in two (preferably three) filters gives us a crude spectral type, the first step to a composition (and therefore mass).
Still, Rubin isn’t alone, nor should it be. An entire cohort of telescopes around the world exists to take newly-discovered phenomena (asteroids, comets, novae, supernovae, gamma-ray bursts, possible gravity-wave detections, etc.) and pin them down further. This telescope/instrument is one of them. SOXS will gather a true spectra, expanding upon Rubin’s color index. And it will do so with a nontrivial (3.58m) aperture- important for near-Earth asteroids, which recede quickly and dim rapidly.
The era of asteroid/comet discovery is upon us. The floodgates are about to be unleashed. These photons are raining down on us constantly, and we are gaining the means to collect them.