Welcome to the July night sky. This is the month that has the warmest nights in the northern hemisphere.
On July 6, the Earth is at its aphelion point in its orbit, so it is at its furthest away from the Sun, so making our northern hemisphere summers not quite so hot as they could be.
During July evenings, the planet Venus is shining brightly high in the western sky and, during the first week of the month, it is close to the faint planet Mars and the white star Regulus, all in the constellation of Leo.
Before dawn in July, the gas giant planet Jupiter is to be seen high and bright over in the east in the constellation of Aries and the ringed planet Saturn, at the same time, is due south in the constellation of Aquarius. Saturn will be at opposition at the end of August.
July has only two major meteor showers – the Alpha Capricornids and the Delta Aquarids; both are to be seen during the last week of the month.
The constellations of summer are now well seen towards the south and, low down in this direction, we start with Scorpius the Scorpion. This star group really does look like its namesake, with the head and the claws of the Scorpion seen up towards the west, and the tail of the Scorpion extending down towards the horizon, with an upward curl and a group of stars forming the sting at the end.
Just above the sting, there is a very faint star possibly invisible by the unaided eye. This star appears unremarkable, but, through a small telescope, it is in fact a triple-star system with two stars slightly smaller and fainter than our Sun that are seen very close together and, further away, a much fainter Red Dwarf star just 1.4% as bright as our Sun.
Orbiting around this Red Dwarf, at least two exoplanets have been found. This triple star system is called Gliese 667 and the Red Dwarf is named 667 C – consequently, its orbiting planets are called 667Cb and 667Cc. These planets are at least two to three times larger than the Earth and they orbit the Red Dwarf star in seven days and 28 days respectively.
These planets may well be suitable for human life, especially the outmost that orbits in 28 days. This star system is relatively close to us at about 23 light years away. There are other Earth-like exoplanets, but they are more than 100 years away. There is, of course, Proxima Century B at only four light years away, but it orbits an active Ref Dwarf star and may be tidally locked and not so suitable for humans.
The sky seen from the surface of the Gliese 667 Cc planet would be amazing with three Suns seen in a bright pink sky.
To the east of Scorpius, we have the constellation of Sagittarius the Archer. This star group contains the centre of our galaxy and has the richest star fields in the whole night-sky. Overhead in July evenings, we now have the three bright stars of the summer triangle – Vega, Deneb, and Altair.
The Moon is full on the 3rd, last quarter on the 10th, new on the 17th and first quarter on July 25.
Clive Jackson is the director of the Camera Obscura – Tavira EYE attraction, located near the Castle of Tavira. Specialising in education and public outreach.
281 322 527 | [email protected] www.torredetavira.com
To see the July Sky Map click on the pdf link below