Astronomy

The Night Sky

Pleiades to Hyades…. Stretching almost 20 degrees from top to bottom, across the dusty constellation Taurus. It begins at the Pleiades and ends at the Hyades, two star clusters recognized since antiquity in Earth's night sky. At the top, the compact Pleiades star cluster is about 400 light-years away. The lovely grouping of young cluster stars shine through dusty clouds that scatter blue starlight. At bottom, the V-shaped Hyades cluster looks more spread out in comparison and lies much closer, 150 light-years away. The Hyades cluster stars seem anchored by bright Aldebaran, a red giant star with a yellowish appearance. But Aldebaran actually lies only 65 light-years distant and just by chance along the line of sight to the Hyades cluster. Source credit: https://science.nasa.gov Image credit: Amir H. Abolfath (TWAN)

WELCOME TO THE SEPTEMBER EDITION OF NIGHT SKY WHEN, FOLLOWING THE AUTUMN EQUINOX, WE WILL BE ABLE TO ENJOY THE RETURN OF LONGER NIGHTS AGAIN AS AUTUMN ARRIVES

The 22nd of September is the Autumnal Equinox, when day and night will be of equal duration around the planet. Each night, after that, will become a little longer as the Earth continues on its orbit around the Sun. Some of the special events and views we can observe this month are: the return of the beautiful Hyades, Venus - our evening star - shining so brightly on the horizon, a glimpse of the planet Uranus, and of course some spectacular views of the Milky Way in our very dark skies here, particularly if you are somewhere with very little light pollution. This month we will also explore a little more 'astronomy jargon', focus on the constellation of Auriga and take a look back at astronomy and space news in our feature 'This Month in Astro History'. A few of the Constellations and Asterisms which can be observed across the skies will be: The Summer Triangle - a bright shining asterism found high towards the south. The Great Square of Pegasus - an asterism found in the constellation of Pegasus, high in the southeast. Capricornus - a constellation low in the southern sky, where you will find the Planets Saturn and Jupiter this month. All of these constellations and others of course, can easily be found with the aid of a free online sky chart or app such as 'Stellarium'. Before observing it is best to allow your eyes around 30 minutes to become dark adjusted, then, the longer you look, the more you will see!

The Moon and Planets in September

The New Moon will be on the 7th this month (Day 1 in its cycle of phases) and the Full Moon will be on the 20th (Day 14 in its cycle). Depending upon your exact position the Full Moon will be rising just before 1a.m. on the 23rd. We should be able to see, on the 9th, a lovely grouping in the southwest of a thin crescent Moon, Venus and Spica. Look just after sunset. From the 16th to the 18th from around 9pm, a waxing gibbous Moon will be seen passing just below the Planets Saturn (to the right) and Jupiter (further to the left). The waning gibbous Moon will pass below the Pleiades and the star Aldebaran on the evenings of the 25th and 26th. This can be seen shortly after dark when the Moon has risen in the east. On the night of the 26th we can observe the Moon near to Aldebaran and the beautiful open cluster of Hyades. This distinctive 'V' form is part of the constellation of Taurus.

Shining a light on Astronomy Jargon : 'Open Clusters'

Two 'Open Clusters' which we can find quite easily in the skies again at this time of the year are: 'The Pleiades' and 'The Hyades'. These two beautiful open clusters are fine examples of over 1000 which sit in the spiral arms of our Galaxy. Open Clusters are made up of stars which are all the same age, having been born inside a parent nebula. The open clusters will be situated within the Galaxy's disc shape where gas and cloud dust give rise to star formation. The Pleiades open cluster for example, is made up of around 500 stars, the brightest of which are visible to the naked eye. In time, the stars of an open cluster will move away from one another, and so our views will be forever changing....

Object of the month: The Milky Way

Our own Galaxy, The Milky Way is one of perhaps hundreds of billions of Galaxies in the Universe. The Milky Way is made up of stars, gas and dust which are gravity bound. Between 200 and 400 billion stars form the spiral shape and part of which we can see on a dark clear night as a cloudy glowing band moving across the sky. The Galaxy measures around 100,000 light years across and 200,000 light years in depth. A light year is how far light travels in one year. Light travels at 300,000km in one second. So we are in fact, really looking back at how things looked in the past! When we look in the direction of the constellations of Scorpius and Sagittarius we are really observing the central area of our Galaxy which is known as 'The Bulge'.

Astronomy Challenge! - Can you spot the Planet Uranus?

The Planet is so far away from the Sun it reflects very little light and so is always a challenge to spot in even clear dark skies such as ours. The best time to try to spot the Planet will be after midnight and before the Moon rises. The first few nights of September will have the thinnest crescent Moon so perhaps provide the best chance to search for it. It will be just visible to the naked eye as a faint star in very good seeing conditions. With binoculars it is easy to find sitting at a '2 o'clock' position from The Pleiades cluster. Good luck and do let us know on our Facebook page if you spot it.

Meteor Showers in September: The Alpha Aurigids

This meteor shower could be a little less spectacular in comparison with the Perseids from August - I hope you spotted some! The Alpha Aurigids will be active during the first week of September with the peak being on the 1st of the month. The Aurigids may extend into October. The maximum hourly rate of these meteors will be 7, however, with the Moon less bright during its waning crescent phase, conditions for observing should be reasonable. The meteors of the Aurigids will all seem to emanate from a similar area of the sky, moving in any direction. They can be fairly bright and so easier to spot. You may also see a number of meteors known as 'Sporadics' which are not related to this shower. Sporadic meteors can appear from any area of the sky at any time and are most frequent in the month of September. This may make up for the slight lack of activity in the Aurigids.

This month in Astronomy and Space History

51 years ago: On September the 12th 1970, the Luna 16 Robotic probe was launched on a Proton K rocket by the former Soviet Union. It landed on the Moon on the 20th and performed the first automated lunar sample retrieval and returned to Earth on the 24th. 16 years ago: On September the 30th 2005, a Soyuz rocket was launched from Baikonur, Kazakhstan carrying a NASA astronaut, a Russian cosmonaut, and an American tourist to the International Space Station. The International Space Station continues to be a real success story of international cooperation. It was so good to hear children from our village talking so enthusiastically during our '#onthemoonagain' night about the current French Astronaut Thomas Pesquet, as the Space Station made a pass overhead. We waved and they were convinced that they could see him waving back!

By Claire Wardlaw

Claire Wardlaw, originally from Edinburgh, lives in the Charente with her husband. Since their move nearly 6 years ago, Claire has become passionate about astronomy