Sky Watch 6 : 22nd May - Finding Boötes - the Herdsman

When we started our Sky Watch articles, we could go out at 9pm and view the Plough as the stars started to appear for the night. Now if we go out at 10pm, it still is not dark - so if you want to look at the night sky over the next few months, you have to be prepared to go outside later. I’m suggesting that you go out at 23.30 this week. The reason for that is you will be able to find your starting point easily as it will be directly above your head - the Zenith.

The Plough has moved during our sessions so that the end star of the handle is at the Zenith. Americans call the Plough the Big Dipper from cowboy days when a cowboy would dip a saucepan-like pan into a trough of water without having to get out of the saddle. The handle is curved and this week I want you to follow the curve round towards the southerly direction. As you curve round there is one bright star in the track - an orange/red giant named Arcturus, a star x25 larger than our Sun. This is the brightest of all the stars in the northern celestial hemisphere and 4th brightest in the night sky. Light reaching us this week will have left Arcturus in 1983! The colour of the star tells us its surface temperature - quite a cool 3,500ºC compared with other stars.

Once you have found Arcturus, use this to star hop around the constellation shown in the drawing above - it is quite a large shape and is very impressive in our spring/summer night sky.