Get smartphones out to capture harvest moon
For their own reasons meteorologist have designated that autumn starts on September 1. However, as all astronomers know, summer changes into autumn at the time of the autumn equinox.
Both equinoxes and solstices are key events in the astronomical calendar. There are two equinoxes (spring and autumn) and two solstices (summer and winter) each year.
The specific dates are not the same each year due to the Earth's elliptical orbit round the sun. In January the Earth is closest to the sun and is known as perihelion, while in July the Earth is at its furthest distance, known as aphelion. This seems contradictory as one would think that we would be closest in the warmer summer months. However the energy we receive from the sun depends very much more on the tilt of the Earth rather than the distance.
The September equinox is when the sun shines directly on the equator and the length of the day and night are nearly equal. This can happen at any time between September 21 and 24, and this year is on September 23 at 08.50 BST.
Before that on September 14, just after 8pm, we see the harvest moon rise in the east. The term originates from the native American Indians and is the name given to the full moon nearest the autumn equinox. With clear skies it will be a spectacular sight which is easily captured on any smartphone, so try your luck.
For those who know their constellations the Great Square of Pegasus dominates the late evening skies confirming the transition from summer into autumn. The number of visible stars inside the square on a cloudless night is a good indicator of how dark your local sky is. If you can only see one or two then you suffer serious light pollution, while 13 or more suggests a very good dark sky.
If you enjoy a clear southern horizon then the early evening gives you the opportunity to seek out a number of planets. Jupiter will be visible in the early evening in the south west and basic binoculars will reveal the patterned disc and the four Galilean moons. An even better sight is the ringed planet and well worth the effort.
The rings of Saturn are a 'must see' sight even in binoculars, but a small telescope will give you the real 'wow' factor.
Throughout the early part of the month early risers will be able to spot the bright International Space Station speed across the dawn sky. However the more relaxed will have to wait until the 19th when it will be visible in the evening sky. It is easily recognised as it will be the brightest object moving across the sky, although it will only be visible for a few minutes.
Autumn is the start of a new observing season for many stargazers. Shropshire Astronomical Society meets monthly on the second Saturday at Little Ness Village Hall and on the third Saturday at Rodington Village Hall, and always welcomes experienced or novice stargazers. For further information visit www.shrophire-astro.uk
Steve Szwajkun is a member of Shropshire Astronomical Society