Age: 26 days old
Phase: Waning Crescent
Distance: 404,899 km
Ian Morison tells us what we can see in the northern hemisphere night sky during September 2014.
The Summer Triangle consisting of the stars Vega, Deneb and Altair is still high in the sky. The asterism of the Northern Cross, near to Deneb, contains the multicoloured double star Albireo. Another double star, Epsilon Lyrae, can be found using binoculars near to Vega, and a telescope reveals that it is itself a pair of doubles. The constellation of Delphinus is below the Summer Triangle, with Aquarius and Capricornus further down still. The Square of Pegasus rises in the east as the evening progresses, and following the arc of the head of Pegasus leads to the globular cluster M15, while the top-left corner of the Square (or, alternatively, the topmost stars of Cassiopeia) can be used to locate the Andromeda Galaxy. Perseus is in the north-east, below Cassiopeia, and binoculars show that the Double Cluster, a pair of open star clusters, lies between them.
- Jupiter, shining at magnitude -1.8, begins September 2.5 degrees from M44, the Beehive Cluster. It is moving through Cancer towards Leo, rising 2.5 hours before the Sun at the start of the month and 4.5 hours before it at the end. Jupiter's disc grows from 32.1 to 33.6" in angular diameter over the month, allowing the equatorial bands and Galilean moons to be seen.
- Saturn, at magnitude +0.6 and 16" across, can be seen low in the south-west after sunset, lying in Libra. It is 20 degrees above the horizon an hour after sunset at the beginning of the month, dropping to 10 degrees by the end, and will soon disappear behind the Sun. Saturn's rings are inclined at 23 degrees to the line of sight, giving a good view, and the planet's largest moon, Titan, should be visible through a telescope.
- Mercury is not readily visible this month, due to its low elevation. It may be spotted around the 20th of the month using binoculars - after the Sun has set - some 5-10 degrees above the horizon and around 25 degrees to the left of where the Sun has gone down, shining at magnitude 0. Mercury is just 0.5 degrees below the first-magnitude star Spica, in Virgo, on the 20th.
- Mars moves quickly eastwards, progressing from Libra into Scorpius and ending the month close to the red star Antares. During September, it dims from +0.6 to +0.8 in magnitude and shrinks from 6.8 to 6.1" across. It is low in the south-west at sunset, with the Earth's atmosphere making it difficult to see surface details. Mars lies halfway between Saturn and Antares on the 12th, and 0.5 degrees above Delta Scorpii on the 17th.
- Venus rises in the east-north-east an hour before sunrise at the beginning of September, and only half an hour before it at the end. It can be seen in Leo early in the month, positioned to the lower left of Jupiter and shining at magnitude -3.9.
- Neptune can be spotted using binoculars or a small telescope this month, sitting in Aquarius with a magnitude of +7.9. It reaches an elevation of 27 degrees when due south, shortly after midnight BST (British Summer Time, 1 hour ahead of Universal Time). A telescope of 8" in aperture should be able to pick out its largest moon, Triton.
- Venus is just 1 degree from the bright star Regulus in Leo half an hour before sunrise on the 5th.
- The planets Mars and Saturn are close to the star Antares in the south-western sky an hour after sunset on the 5th, but a low horizon is required to see it.
- Jupiter is 6 degrees from a thin crescent Moon before dawn on the 20th.
- Saturn, Mars and a crescent Moon appear together in the sky after sunset on the 27th and 28th.
- The Alpine Valley is a nice feature of the Moon to observe on the 2nd and 14th, when it is close to the limb. It lies in the Apennine mountain chain that marks the edge of the Mare Imbrium, and a thin rill can be seen running along it using a medium-sized telescope. The craters Plato and Copernicus appear well around the same dates.
Claire Bretherton from the Carter Observatory in New Zealand speaks about the southern hemisphere night sky during September 2014.
The spring equinox arrives this month, so the nights are rapidly getting shorter. The bright stars Vega and Canopus mark the northern and southern horizons at dusk, with the band of the Milky Way passing overhead between them. Vega is part of the Winter Triangle, along with Deneb and Altair. Between Vega and Altair is the lovely double star Albireo, marking the beak of Cygnus the Swan. The winter constellations of Scorpius and Sagittarius are sliding towards the western horizon night by night, with Orion rising opposite them as they set. Between them are Capricornus, Aquarius and Pisces.
Capricornus, often depicted as a cross between a goat and a fish, appears as an elongated triangle of stars, while a smaller triangle marks its head and horns. Its brightest star is Delta Capricorni or Deneb Algedi, and it changes significantly in brightness because it is an eclipsing binary, in which two stars partially block one another from our view as they orbit. The system is now known to contain four stars. Alpha Capricorni, or Algedi, is a double star whose members can just be distinguished with the naked eye, but the two stars are not in a binary system as they are at very different distances from us. The watery constellations in this part of the sky are associated with autumn and winter rains in the northern hemisphere, and to the south-east of Capricornus is Piscis Austrinus, the Southern Fish. The bright star Fomalhaut, marking its mouth, has a planetary companion that was directly imaged by the Hubble Space Telescope.
The constellation of Aquarius the Water-carrier, lying between Fomalhaut and Altair, contains a number of beautiful deep-sky objects. M2 is a globular cluster near to the third-magnitude star Beta Aquarii. Visible in binoculars, a telescope of 20 centimetres in aperture shows up individual stars. The Helix Nebula, or NGC 7293, is a planetary nebula positioned south-west of Delta Aquarii that appears as a hazy circle in binoculars. A telescope reveals the darker area in the centre, while a long-exposure photograph brings out the nebula's colours. Pisces, Cetus and Delphinus are more water-themed constellations in this area of the sky.
- Mars and Saturn are about halfway up the north-western sky in the evening at the beginning of the month, and are joined by a crescent Moon on the 1st. Saturn is sliding towards the western horizon, but Mars moves east on its faster orbit and, at the end of the month, passes close to its namesake, the red star Antares - the 'Rival of Mars'.
- Mercury makes its best appearance of the year this month, joining Mars and Saturn in the western sky after dark. Its fast, close orbit means it never gets far from the Sun in our sky, but it reaches eastern elongation - its greatest separation to the east - on the 22nd. Mercury passes close to the star Spica, in Virgo, on the 20th.
- Jupiter shines brightly in the north-east in the morning, rising around 1.5 hours before the Sun by the middle of September. Binoculars or a telescope show its four largest moons.
- The last of three 'supermoons' of 2014 occurs on the 9th, when the Moon is almost full at its closest approach to the Earth and looks bigger and brighter than usual.
Wednesday, July 30, 2014
The Abrams Planetarium Night Sky Notes has been discontinued. Please find Abrams Planetarium on Facebook and Twitter. Also look at the Abrams Planetarium Sky Calendar for astronomical information. Visit abramsplanetarium.org for more information.
Tuesday, July 22, 2014
The waning crescent Moon is near Aldebaran. Look east two hours before sunrise.
Monday, July 21, 2014
The waning crescent Moon is near the Pleiades star cluster. Look east two hours before sunrise.
Sunday, July 20, 2014
Mars is 3.6 degrees to the upper left of Spica.
Saturday, July 19, 2014
The Last Quarter Moon is in the southeast an hour before sunrise.
Friday, July 18, 2014
Mercury is 6.3 degrees to the lower left of Venus. Look ENE 45 minutes before sunrise.
Thursday, July 17, 2014
Mars is 2.3 degrees to the upper left of Spica.
Wednesday, July 16, 2014
Mercury is 6.2 degrees (minimum distance) to the lower left of Venus. Look ENE 45 minutes before sunrise.
Tuesday, July 15, 2014
Mars is 1.6 degrees to the upper left of Spica.
Monday, July 14, 2014
Mars is 1.4 degrees to the upper left of Spica.
Sunday, July 13, 2014
Mars is 1.3 degrees to the above of Spica. (closest approach)
Saturday, July 12, 2014
Mars is 1.4 degrees to the upper right of Spica.
Friday, July 11, 2014
Mars is 1.6 degrees to the upper right of Spica.
Thursday, July 10, 2014
Mercury is 8 degrees to the lower left of Venus. Look ENE 45 minutes before sunrise.