Ganymede, one of the four robotic telescopes at ESO’s newest planet-hunting SPECULOOS Observatory, has obtained its first engineering and calibration image — a process known as first light. SPECULOOS will focus on detecting Earth-sized exoplanets orbiting nearby ultracool stars and brown dwarfs. The new image, however, is obviously not of a faint star, but of a galaxy called NGC 6902.
This image from ESO’s SPECULOOS Observatory shows the spiral galaxy NGC 6902. Image credit: ESO.
SPECULOOS (Search for habitable Planets EClipsing ULtra-cOOl Stars) is a project sited at ESO’s Paranal Observatory in Chile’s Atacama desert.
The facility comprises four telescopes of Ritchey-Chrétien design, each with a 1-m primary mirror and cameras that are highly sensitive in the near-infrared. While this radiation is slightly beyond what human eyes can detect, it is the primary emission from ultracool stars and brown dwarfs.
The telescopes are named after four of Jupiter’s moons: Io, Europa, Ganymede and Callisto.
SPECULOOS aims to find the most suitable terrestrial planets for detailed atmospheric characterization by future giant observatories, such as ESO’s 39-m Extremely Large Telescope and the NASA/ESA James Webb Space Telescope.
Before a telescope starts its primary mission it must successfully undertake an event called ‘first light:’ the first time it is used for a scientific observation.
Astronomers typically pick well-known objects for this initial test of a telescope’s capabilities, which is half demonstration and half celebration.
In this case, the SPECULOOS team settled on NGC 6902 as the first-light target for the Ganymede telescope.
The result was this stunning image of the spiral galaxy, which is found about 120 million light-years from Earth in the constellation of Sagittarius.
The galaxy’s spiral arms swirl outwards from a bright center until they dissolve into streams of blue haze at the galaxy’s edge.
