THE NIGHT SKY FOR OCTOBER 2014
Ian Morison from the Jodrell Bank Centre for Astrophysics tells us what can be seen in the night sky this month.
Ian Morison tells us what we can see in the northern hemisphere night sky during October 2014.
The constellations of Cygnus, Lyra and Aquila are almost overhead in the evening, with their bright stars Deneb, Vega and Altair forming the Summer Triangle. The Square of Pegasus is to the lower left of Cygnus. If you move from its top-left to the next bright star, fork a little to another star and go the same distance again, before turning sharply right to find another star, then carrying on a little further brings you to the fuzzy glow of the Andromeda Galaxy. If you go back to the sharp right turn and carry on the same distance again, binoculars may pick up the Triangulum Galaxy as well. Andromeda can also be found by moving along the Milky Way from Deneb to the W-shape of the Cassiopeia constellation and following the V of the three highest stars like an arrow. Moving a bit further along the Milky Way, and dropping down between two stars towards Perseus, you can locate the beautiful Double Cluster.
- Jupiter, at magnitude -1.9, rises around 02:30 BST (British Summer Time, 1 hour ahead of Universal Time, UT) at the beginning of the month, 7 degrees to the lower left of M44, the Beehive Cluster. It passes from Cancer into Leo on the 14th. It brightens to magnitude -2 and rises well over an hour earlier by the end of the month, which seems earlier still for observers whose clocks go back at the end of October. Jupiter's disc grows from 34 to 36" during October as the Earth approaches it, and a small telescope can reveal its equatorial bands and four largest moons. The Great Red Spot is also visible at certain times, and appears to be shrinking slightly.
- Saturn is past its best apparition of the year, but can still be seen 7 degrees above the south-western horizon an hour after sunset at the beginning of the month. It lies in Libra and shines at magnitude +0.6.
- Mercury is well placed in the pre-dawn sky at the end of the month. On the 22nd, it has a magnitude of +2 and rises at 07:00 BST, reaching 8 degrees above the horizon by dawn and sitting 11 degrees from the Sun in our sky. Be careful not to look for it once the Sun has risen, as your eyes could be damaged. Mercury reaches western elongation (its furthest point west from the Sun in the sky) on the 1st of November, when its disc measures 7" across and is 50 percent illuminated.
- Mars starts October in the often-forgotten zodiacal constellation of Ophiuchus, moving into Sagittarius on the 21st. Its magnitude dims from +0.8 to +0.9 over the month, while its angular size drops from 6 to 5.6". It sets about 2.5 hours after the Sun for the whole month, so you may be able to spot it, but it is hard to make out surface details.
- Venus rises half an hour before the Sun at the start of October, shining at magnitude -3.9, but is soon lost in the morning glare and moves behind the Sun (superior conjunction) on the 25th, not to reappear for around a month.
- The planet Uranus reaches reaches opposition (opposite the Sun in the sky) on the 7th, so it is at its closest point to the Earth and lies due south around midnight UT. At magnitude +5.9, binoculars can locate it in the southern part of Pisces, to the east of the Circlet asterism that forms the head of one of the Fish, and is 3 degrees south of the line joining the fourth-magnitude stars Epsilon and Delta Piscium. Its highest elevation is about 45 degrees, attained around midnight. A telescope of some 4.5 inches in aperture should show the planet's pale turquoise disc, 3.6" across. An 8-inch telescope may reveal cloud formations, which are currently more prominent than usual.
- Jupiter is 10 degrees to the east of a waning crescent Moon in Leo an hour before sunrise on the 17th.
- The Orionid meteor shower may produce up to 10 visible meteors per hour between 01:00 and 05:00 BST from the 17th to the 23rd. The radiant of the shower, which originates from Comet Halley, is to the upper left of Orion's red giant star, Betelgeuse.
- Mercury lies 7.5 degrees below a thin crescent Moon half an hour before sunrise on the 22nd, but you will need a low eastern horizon to see it.
- The waxing crescent Moon occults (passes in front of) Saturn from around 16:59 to 18:03 on the 25th for UK observers, with exact times varying from place to place and in other countries. It is hard to spot, coming before sunset and dropping from 12 to 6 degrees in height during the occultation. The Moon, just 3 percent illuminated, covers Saturn with its dark limb and uncovers it from its bright side.
- Mars passes just 6 degrees below a thin crescent Moon an hour after sunset on the 27th.
Claire Bretherton from the Carter Observatory in New Zealand speaks about the southern hemisphere night sky during October 2014.
The winter constellation of Scorpius (Te Matau a Maui to Maori) is dropping towards the western horizon, and sets by midnight NZDT (New Zealand Daylight Time, 13 hours ahead of Universal Time). Meanwhile, Orion is rising in the east, along with the other summer constellations of Taurus and Canis Major. Mercury can still be spotted low in the west-south-west during the first week of October, while Saturn is below Scorpius and sets around 22:00 NZDT. Mars continues to hang halfway up the western sky after dark. Comet Siding Spring C/2013 A1 passes within 138,000 kilometres of Mars on the 19th-20th, and may be visible in binoculars from Earth. Approaching Mars from above as seen from the southern hemisphere, it is 4.4 degrees away on the 15th, then passes beneath it and moves to the lower left of the globular cluster NGC 6401 on the 20th. Uranus is in Pisces, to the north-east, and Neptune is in Aquarius, higher in the north, but neither can be seen with the naked eye. Jupiter is the brightest planet currently in the sky, and rises in the north-east around 04:30 NZDT at the beginning of the month, its largest moons visible in binoculars.
Pegasus, the Winged Horse, straddles the northern horizon in the evening. Identified by a large square of stars, its brightest member is the orange supergiant Epsilon Pegasi, or Enif, named after the Arabic word for the Horse's nose. Nearby is the M15, which may be the densest globular cluster in our Galaxy. With a magnitude of +6.2, it appears as a fuzzy glow in binoculars, while a telescope can pick out chains of stars radiating out from the core. M15 also contains the planetary nebula Pease 1, the first such object to be found within a globular cluster. At magnitude +15.5, a telescope of 30 centimetres in aperture is required to see it. Alpheratz, the star at the bottom of the Great Square of Pegasus, is a great place from which to star-hop to the Andromeda Galaxy, which appears near the northern horizon in southern hemisphere skies only at this time of year. To find it, move along the uppermost of two chains of stars that extend east from Alpheratz, pass Delta Andromedae, turn sharp right at Mirach, carry on to Mu Andromedae and then go the same distance again to the galaxy. At 2.5 million light-years' distance, it is the most distant object normally visible to the naked eye from Earth.
Compiled by Ian Morison
- The full Moon provides a total lunar eclipse over much of the Earth on the night of the 8th-9th, beginning some two hours after moonrise for observers in New Zealand. As the Moon moves through the Earth's shadow, a penumbral phase (beginning around 21:15 NZDT) is seen when the Earth blocks only part of the Sun's light, an umbral phase (around 22:14) follows when the centre of the Earth begins to cast its shadow, and totality (23:25 to 00:24) occurs when the Earth puts the Moon into full darkness. Even then, refraction of sunlight by the Earth's atmosphere gives the Moon a red tint.
- The zodiacal light can be spotted this month, making a triangular glow in the western sky after sunset. Caused by the reflection of sunlight by dust in the plane of our Solar System, this weak glow requires a dark, clear sky in order to be seen. It appears in the zodiacal constellations because it lies around the ecliptic, and the steep angle of the ecliptic at this time of year pushes it higher into the sky. The time around new Moon, on the 24th, is best for observing it.