Astronomy

IC 10 is a dwarf irregular galaxy that’s a member of our Local Group. Intense star formation here leads to its ‘starburst’ classification. Image: Leonardo Orazi. Galaxies are everywhere, including within the unlikely Winter Milky Way territory of Cassiopeia. There are three well known though rather elusive Local Group galaxies found here. NGC 147 and 185 are satellites of the mighty Andromeda Galaxy (Messier 31), the Local Group’s dominant force. Though IC10 is not gravitationally bound to Messier 31, it appears to be part of the Andromeda subgroup, along with Messier 33, the Triangulum Galaxy. AN Graphic by Greg Smye-Rumsby. NGC 147: a companion of the mighty Andromeda Galaxy Dwarf spheroidal galaxy NGC 147 (Caldwell 17) is one of mighty Andromeda Galaxy’s (Messier 31) retinue. NGC 147 i...

Perhaps you’ve heard of the popular Netflix show and the science fiction novel on which it is based, The Three-Body Problem, by Chinese science fiction author Liu Cixin. The story’s premise is a star system where three stars orbit each other, which leads to periodic destruction on a planet orbiting one of them. As Isaac Newton described in his Philosophiæ Naturalis Principia Mathematica, the interaction of two massive bodies is easy to predict and calculate. However, the interaction of three bodies leads is where things become unpredictable (even chaotic) over time. This problem has fascinated scientists ever since and remains one of the most famous unsolved mysteries in mathematics and theoretical physics. The theory states that the interaction of three gravitationally bound objects will...

Fig. 1. Rev. Ellison as he appeared on the frontispiece of the 2nd edition of The Amateur’s Telescope Rev. W.F.A. Ellison  Rev. William Frederick Archdall Ellison was the sixth Director of the Armagh Observatory and was appointed to the role on 15 October 1918. He would remain in this position until his death on 31 December 1936. During that time, he made several telescopes and mirrors, both for the Observatory, and to supplement his income, which was very low compared to other Astronomers in the United Kingdom. He had been making mirrors for twenty years when he arrived in Armagh and had built up a reputation as by publishing articles and pamphlets about telescope-making in The English Mechanic and other periodical journals.   Fig. 2. The Ellison Reflector as it appears in The Amateurs Te...

This spectacular ‘Ring of Fire’ eclipse of the Sun took place on 20 May 2012. Image: Kevin Baird. On 2 October one of the most spectacular events in nature takes place. A annular eclipse, popularly described as a ‘Ring of Fire’ eclipse, is visible along an east-to-west orientated path in the far south of South America, crossing Chile and Argentina. Unlike at a total eclipse of the Sun, the Moon’s shadow stops just short of Earth’s surface, leaving a thin band of the Sun’s blinding photosphere encircling the Moon’s silhouette.  A large area of South America experiences a partial eclipse. In Buenos Aires, Argentina, 53.3% of the Sun is hidden by the Moon at 5.23pm. The eclipse takes place between 15:43h and 21:47h UT, with the maximum duration of the annular eclipse lasting seven minutes an...