July brings warmer nights to lie back in a recliner chair late into the night and observe the summer constellations as they wend their way across the night sky.
Of course they are not moving in the sky – we are! As the Earth orbits the sun, so our position changes the constellations we see as the year progresses.
Planets
Jupiter is setting now by 10:30pm but can still be caught as the sky darkens. The “King of Planets” is always a majestic sight in a small to moderate telescope, but binoculars easily show the four moons as specks of light as they orbit the planet.
Mars is now setting as the month moves on and drifts out of Scorpius towards the constellation of Libra (The Scales). Libra is not particularly easy to spot, so use Mars as your guide whilst it is there. Mars does need necessarily need a large telescope to observe, but it does need quite a high power to observe any detail.
Saturn is still sitting not far from Antares as described last month. Binoculars show that the planet is not quite the right shape, but a small telescope of say 70mm size lens show the rings quite clearly.
Constellation
Following eastwards from Scorpius, this month’s constellation is Sagittarius (The Archer). Sagittarius is also known as “The Teapot” and holds many deep sky splendours which are relatively easy to spot in binoculars.
In Greek mythology Sagittarius is a centaur (half human half horse), with the tip of the centaur’s arrow aimed at Antares, the heart of Scorpius (the Scorpion), poised to attack should the scorpion get out of line!
To locate Sagittarius on 23rd July, at 11:30pm, look southwards and see if you can spot the “Teapot” shape of the constellation; this is an area rich in globular clusters, gravitationally bound “balls” of stars which make up the oldest structures in our galaxy. At the tip of the “lid” of the Teapot lie Messiers (M) 22 and 28. M22 is amongst the most spectacular globulars in the sky. Most globulars appear as simple fuzzy blobs, but with a moderate sized telescope, you can begin to pick out some of the many stars in the cluster as dusk falls toward darkness. M28 comes a very good second in the observation stakes with 5 stars being spotted in a modest telescope.
Move your binoculars a little westwards and you can spot Messier 8 “The Lagoon Nebula”. This gently glowing nebula is a patch comprising mainly hydrogen gas in which stars are forming. The nebula takes its name from the feature of a “lagoon” separating two areas of the nebulosity. Take a while to scan your binoculars around the “steam” rising from the Teapot and you will be amply rewarded with star clouds, smaller globular clusters, in the midst of the Milky Way.
Moon
For this month’s lunar feature, have a look for the crater Tycho, which sits on the south of the Moon’s “face”. On the night of the 16th at around 10.30pm, point your binoculars to the southern part of the Moon and you can see Tycho surrounded by a magnificent spread of “rays”, the dust and rock ejected from the impact of the crater’s formation some 100 million years ago. Tycho is around 85km in diameter with its floor over 4,000 metres lower than the crater rim. As one of the moon’s most prominent features, Tycho has a central peak which rises some 2,000 metres from the crater floor, with the ray system extending up to 3500km miles from the crater’s centre. It is sobering to think that Tycho was formed by the impact of a lump of rock some 8 to 10 km in size.
Jonathan Gale
