Eye on the sky: Twin Ring Bling
It was 153 years ago this month that German astronomer Friedrich Winnecke discovered galaxy NGC 1398, a departure from the comets and nebulae that were his usual quarry. Now this new image taken with the DECam, the Dark Energy Camera mounted on northern Chile’s Víctor M Blanco Telescope, captures the galaxy in exquisite detail. It’s part of the Dark Energy Survey (DES), a project that has mapped 300 million galaxies to shed light on the elusive nature of dark energy.
Sixty-five million lightyears from Earth in the Fornax constellation, at 135,000 lightyears across NGC 1398 is slightly larger than our Milky Way. Unusually it has a double ring appearance, its delicate, feathery spiral arms forming a tightly-wound inner circle bejewelled with stars. Like two-thirds or so of spiral galaxies, NGC 1398 has a central bar of stars, albeit masked by a super-bright core. Despite their ubiquity it’s not yet understood how, or even whether, such bars affect a galaxy’s form or behavior.
In at the death
HUBBLE SPACE TELESCOPE/LICK OBSERVATORY, 21 OCTOBER 2021
For the first time, a star has been witnessed selfdestructing in real time. Supernova SN 2020fqv, inside the interacting Butterfly Galaxies NGC 4567 (top) and NGC 4568 (bottom), was watched by multiple groundbased and space telescopes during its explosion. The Hubble Space Telescope even managed to probe the star’s ejected circumstellar disc just hours after its demise. Such an unprecedented data haul could shape an ‘early warning system’ for future supernovae.
New tech gets radar pulses racing
GREEN BANK TELESCOPE, 21 SEPTEMBER 2021
This 1.4-billion-pixel view of Tycho, the massive 86km crater whose bright rays splay out across the Moon’s southern highlands, is the highest-resolution image ever taken from the ground using radar technology. Plans are now under way to scale up the project – which uses synthetic aperture radar (SAR) to translate low-powered radar signals into images – by several hundred times in order to capture more distant objects in the Solar System.
BEPICOLOMBO, 1 OCTOBER 2021
Mercury sails into view as European– Japanese BepiColombo makes its first flyby. Having set off in October 2018, the spacecraft skimmed over the planet at an altitude of just 199km, close enough to pick out impact craters and scarps, and to scoop up data about the magnetic and particle environment over the little-explored southern hemisphere. This is the first of six gravity-assisted manoeuvres that will eventually put the craft in a stable orbit around the planet in December 2025.
Asteroid belters
VERY LARGE TELESCOPE, 12 OCTOBER 2021
From giant icy sphere Ceres, 940km in diameter and classed as a dwarf planet, through weirder peanut and dog bone shapes, right down to 90km-wide Urania and Ausonia, these are 42 of the largest objects in the asteroid belt, the doughnutshaped zone between Mars and Jupiter that swarms with the rocky remnants of our Solar System’s creation.
Spiral galaxy NGC 4666 – HUBBLE SPACE TELESCOPE, 11 October 2021 – CREDIT: ESA/Hubble & NASA, O. Graur. Acknowledgement: L. Shatz 
Composite image of supernova remnant G344.7-0.1 – CHANDRA X-RAY OBSERVATORY/SPITZER SPACE TELESCOPE, 12 OCTOBER 2021 – CREDIT: X-ray: NASA/CXC/Tokyo Univ. of Science/K. Fukushima, et al.; IR: NASA/JPL/Spitzer; Radio: CSIRO/ATNF/ATCA 
Arp 91: interacting galaxies NGC 5953 (below) and NGC 5954 (upper right) – HUBBLE SPACE TELESCOPE, 4 October 2021 – CREDIT: ESA/Hubble & NASA, J. Dalcanton. Acknowledgement: J. Schmidt 
Spiral galaxy NGC 2903 – HUBBLE SPACE TELESCOPE, 25 OCTOBER 2021 – CREDIT: ESA/Hubble & NASA, L. Ho, J. Lee and the PHANGS-HST Team 
Arp 86: interacting galaxies NGC 7752 (larger) and NGC 7753 – HUBBLE SPACE TELESCOPE, 22 OCTOBER 2021 – CREDIT: ESA/Hubble and NASA, Dark Energy Survey, J. Dalcanton; CC BY 4.0 
A gecko-shaped vent in Mars’s Gordii Fossae – MARS RECONNAISSANCE ORBITER, 19 OCTOBER 2021 – CREDIT: NASA/JPL-Caltech/University of Arizona
PHOTOS: DARK ENERGY SURVEY/DOE/FNAL/DECAM/CTIO/NOIRLAB/NSF/AURA IMAGE PROCESSING: T.A. RECTOR (UNIVERSITY OF ALASKA ANCHORAGE/NSF’S NOIRLAB), J. MILLER (GEMINI OBSERVATORY/ NSF’S NOIRLAB), M. ZAMANI & D. DE MARTIN (NSF’S NOIRLAB), NASA/ESA/RYAN FOLEY (UC SANTA CRUZ), NRAO/GBO/RAYTHEON/NSF/AUI, ESA/BEPICOLOMBO/ MTM, ESO/M. KORNMESSER/VERNAZZA ET AL./MISTRAL ALGORITHM (ONERA/CNRS)