Free Astronomy Magazine March-April 2023

45 MARCH-APRIL 2023 the Eagle, the Omega and the Sh2- 54 nebulae; the last of these is re- vealed, in a new light, in this spec- tacular infrared image. Nebulae are vast clouds of gas and dust from which stars are born. Tel- escopes have allowed astronomers to identify and analyse these rather faint objects in exquisite detail. The nebula shown here, located about 6000 light-years away, is of- ficially called Sh2-54; the “Sh” refers to the US astronomer Stewart Sharpless, who catalogued more than 300 nebulae in the 1950s. As the technology used to explore the Universe progresses, so too does our understanding of these stellar nurseries. One of these ad- vances is the ability to look beyond the light that can be detected by our eyes, such as infrared light. Just as the snake, the namesake of this nebula, evolved the ability to sense infrared light to better understand its environment, so too have we de- veloped infrared instruments to learn more about the Universe. Whilst visible light is easily ab- sorbed by clouds of dust in nebulae, infrared light can pass through the thick layers of dust almost unim- peded. The image here therefore reveals a wealth of stars hidden be- hind the veils of dust. This is partic- ularly useful as it allows scientists to study what happens in stellar nurs- eries in much greater detail, and thus learn more about how stars form. This image was captured in infrared light using the sensitive 67-million- pixel camera on ESO’s VISTA tele- scope at Paranal Observatory in Chile. It was taken as part of the VVVX survey — the VISTA Variables in the Via Láctea eXtended survey. This is a multi-year project that has repeatedly observed a large portion of the Milky Way at infrared wave- lengths, providing key data to un- derstand stellar evolution. A myriad of stars is revealed behind the faint orange glow of the Sh2-54 nebula in this new infrared image. Located in the constellation Ser- pens, this stunning stellar nursery has been captured in all its intricate detail using the Visible and Infrared Survey Telescope for Astronomy (VISTA) based at ESO’s Paranal Ob- servatory in Chile. When the ancients looked up at the night sky they saw random patterns in the stars. The Greeks, for in- stance, named one of these “con- stellations” Serpens, because of its resemblance to a snake. What they wouldn’t have been able to see is that at the tail end of this constel- lation there is a wealth of stunning astronomical objects. These include ! A visible-light image of the Sh2-54 nebula, captured by the VLT Survey Tele- scope at ESO’s Paranal Observatory in Chile. At these wavelengths the structure of the nebula is clear and the clouds of dust and gas block the light of stars within and behind it. [ESO] ASTRO PUBLISHING