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April 2014: Only Human

April 2014

In the show this time, we conduct a linguistic interchange with Prof. Ian Shipsey regarding the Large Synoptic Survey Telescope, Indy issues a bulletin acknowledging the latest triumph of computational analysis in astronomy and Ian Morison and John Field describe what the human eye can detect during the nocturnal hours of the lunar period known as April. Meanwhile, our new, more efficient presenters bring us superior odds and ends.

The News

In the news this month: BICEP2 flexes its muscles.

Interview with Prof. Ian Shipsey

Professor Ian Shipsey is a particle physicist at Oxford University, and is involved in the Large Synoptic Survey Telescope (LSST) project. This 8-metre optical telescope is due to begin an unprecedented survey of the sky in 2022, imaging all that it can see and repeating these observations twice a week for 10 years. Prof. Shipsey describes the scope of the measurements that will be done, finding billions of galaxies in the Universe, stars in the Milky Way and small bodies in our Solar System. He talks about the benefits that will emerge, from a better understanding of dark energy through the mapping of galaxies in space and time to a more complete knowledge of potentially threatening asteroids through the cataloguing of 90% of the near-Earth objects that are over 140 metres in diameter. He explains how the vast quantity of data generated by the LSST will be processed using both computers and citizen science, and describes how astronomers will be alerted to transient phenomena detected by the telescope.

The Night Sky

Northern Hemisphere

Ian Morison tells us what we can see in the northern hemisphere night sky during April 2014.

The constellation of Gemini and the planet Jupiter are setting in the west as the Sun goes down. Leo, with its bright star Regulus, is in the south, and to the left of Regulus are the galaxies M95, M96, M66 and M65, which are visible in binoculars or a small telescope. To the left of Leo, more such objects can be found in a region between Coma Berenices and Virgo known as the Realm of the Galaxies, which looks towards the Virgo Cluster. The bright star Arcturus is to the south-east, in Bo”tes, with the circlet of stars called Corona Borealis to its left. The bright star Vega rises in the north-east later in the evening, in Lyra, followed by Cygnus and the Milky Way. Ursa Major is almost overhead, containing the famous asterism of the Plough, or Big Dipper. If you look diagonally up the trapezium-shaped part of the Plough from bottom-left to top-right, and then carry on for the same distance again, you reach the galaxies of M82 and M81. M82, nicknamed the Cigar Galaxy, is a starburst galaxy where many new stars and supernovae can be seen. The middle star of the Plough's handle is actually a double, with two components called Mizar and Alcor, or the Horse and Rider. A telescope shows that Mizar is itself a double star, and another, reddish star appears in the same field of view.

The Planets


Southern Hemisphere

John Field from the Carter Observatory in New Zealand speaks about the southern hemisphere night sky during April 2014.

The daylight hours continue to shorten as the southern hemisphere progresses through early autumn. Three bright planets can be seen in the early evening sky: Jupiter in the north-west, in Gemini, Mars in the north-east, shining with an orange-red hue near to the star Spica in Virgo, and Saturn, which follows Mars in Libra. Mars makes the closest approach to Earth in its current orbit this month, while Saturn's rings and its largest moon, the orange-coloured Titan, are well placed for viewing with a telescope. Mars and Saturn are high in the sky by midnight and above Mars is a kite-shaped quartet of stars in the constellation of Corvus the Crow. Delta Corvi is a wide double star, but there are few other easily-observed objects in the vicinity. Nearby is Hydra the Water Snake, a long path of stars with a distinct group of five stars forming its head.

The winter constellation of Scorpius rises in the east in the evening. Its brightest star, at magnitude +1, is the red supergiant Antares, known as the Rival of Mars because of its colour. It is called Rehua by Māori in Aoteroa (New Zealand), and marks the eye of Māui's fishing hook. This hook is called Te Matau a Māui, for which the back and stinger of the Scorpion's body become the curve and tip of the hook. According to Māori mythology, the great hero Māui used this hook to pull the North Island of New Zealand from the ocean, for which that part of the country is named Te Ika-a-Māui - the Fish of Māui. The tip of the hook crosses a wide and bright part of the Milky Way, and in this part of the sky we are looking towards the Galactic centre, some 30,000 light-years away. The Southern Cross of Crux and its pointer stars are found by running up the Milky Way, as are the Diamond and False Crosses. Crux is called Te Punga in Māori star lore. The hero Tamarereti sailed across the heavens in his Waka, or canoe, placing the stars into the sky, and Te Punga was his boat's Anchor. You can find south halfway between Crux and the bright star Achernar, in Eridanus, by following the line from the top to the base of the Cross. Two-thirds of the way along this line are the Magellanic Clouds, dwarf satellite galaxies of the Milky Way.


Odds and Ends



Show Credits

News:Indy Leclercq
Interview:Prof. Ian Shipsey and Mark Purver
Night sky:Ian Morison and John Field
Presenters:CPU 001 and CPU 002
Editors:Adam Avison, Libby Jones, Indy Leclercq, Mark Purver and Christina Smith
Segment Voice:Iain McDonald
Website:Mark Purver and Stuart Lowe
Website:Mark Purver and Stuart Lowe
Cover art:The first evidence of primordial gravitational waves in the cosmic microwave background (CMB), detected by the BICEP2 telescope. The lines show the magnitude and direction of the linearly polarised component of the CMB; the red and blue patches indicate regions where the direction is twisted clockwise and anticlockwise, which is the giveaway signature of the effect of gravitational waves in the early Universe. CREDIT: BICEP2 Collaboration

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