Owls may be scarce near your favourite viewing spot, but the Northern Hemisphere spring sky contains one celestial owl that you can track down in small telescopes – Messier 97 (NGC 3587). Commonly called the Owl Nebula, M97 is a planetary nebula discovered by Pierre Méchain in 1781 that is currently ideally placed for observation almost overhead at nightfall in the constellation of Ursa Major, the Great Bear.
Comet 41P/Tuttle–Giacobini–Kresák orbits the Sun every 5.4 years and will pass through perihelion (its closest point to the Sun) on 12 April 2017. Motoring through Ursa Major at close to 2°/day during the remainder of March, this fascinating comet with a history of dramatic surges in brightness, passes close to Messier 97 and 108 on the UK night of 22 March.
The creation of a specialised IAU Working Group, the Working Group on Star Names (WGSN), was approved by the IAU Executive Committee in May 2016 to formalise star names that have been used colloquially for centuries. WGSN has now established a new catalogue of IAU star names, with the first set of 227 approved names published on the IAU website.
Each year, NASA’s Chandra X-ray Observatory helps celebrate American Archive Month by releasing a collection of images using X-ray data. Each of these six new images — representing just a small fraction of the treasures that reside in Chandra’s unique archive — also includes data from telescopes covering other parts of the electromagnetic spectrum, such as visible and infrared light.
Investigating the millions of missing stars from the centres of two big galaxies, researchers say they may have solved this cosmic whodunit — and the main culprits are not the usual suspects. While the astronomers confirm that one of the depleted cores is the largest ever detected, they report that it may not have formed in the manner previously thought.
This multicoloured swirl of yellow and blue shows a prominent ring of gas near the North Celestial Pole. The pole appears to be fixed in place, while the rest of the night sky slowly circles around it because of Earth’s rotation. This image comes courtesy of ESA’s Planck satellite, which spent years mapping the entire sky in exquisite detail between 2009 and 2013.
This NASA/ESA Hubble Space Telescope image shows star clusters encircling a galaxy, like bees buzzing around a hive. The hive in question is the edge-on lenticular galaxy NGC 5308, located just under 100 million light-years away in the constellation of Ursa Major. On 9 October 1996, one of NGC 5308’s aging stars exploded as a spectacular Type la supernova.
In this Hubble Space Telescope image we see an irregular dwarf galaxy known as UGC 4459, located in the constellation of Ursa Major (The Great Bear). While UGC 4459’s diffused and disorganised stellar population of several billion sounds impressive, this is small when compared to the 200 to 300 billion stars in the Milky Way.
Having brushed by bright star Arcturus on 1 January, Comet Catalina (C/2013 US10) continues its trek through the constellations of the far north. Now a circumpolar object for the British Isles, in the early hours of 17 January it lies between famous double star Mizar (ζ Ursae Majoris) and the Pinwheel Galaxy (M101), virtually overhead in the UK.
It is known today that merging galaxies play a large role in their evolution, and the formation of elliptical galaxies in particular. However, there are only a few merging systems close enough to be observed in depth. The pair of interacting galaxies seen here — known as NGC 3921 — is one of these systems. But ‘close’ is a relative term: NGC 3921 lies 270 million light-years away.