Pointers

Demonstrate the use of 'pointers' and other techniques to find other celestial objects, including:
i Arcturus and Polaris from the Plough
ii Sirius, Aldebaran and the Pleiades from Orion
iii Fomalhaut and the Andromeda Galaxy from the Great Square of Pegasus

Some stars form natural pointers toward other stars. There are 3 items you need to know for the exam.

 

Plough

The two stars on the pan end of Ursa Major point (from bottom, Merak, to top Dubhe) to Polaris in Ursa Minor.

This is the pole star, Polaris. It points towards the North Pole. If you were at the North Pole, Polaris would be directly above your head. This star has been useful to navigators for centuries because it points north. It is a small fraction away from the North Pole but it is pretty near.

The Plough is also useful to find Arcturus, a red star in Bootes. Follow the path of the 'handle' of the Plough to find Arcturus.

 

Orion

The stars in the belt of Orion can point westwards and down to a very bright star called Sirius, the Dog Star, in the constellation of Canis Major (The Great Dog).

If you follow the path of the 3 stars in the opposite direction you will come to the bright red star Aldebaran in Taurus and the Pleiades Cluster.

 

Square of Pegasus

If you use the bottom right and top left stars of the square you can use a line to find the Andromeda Galaxy which is barely visible on a clear night in an area of low light pollution.

Using the top right and bottom right stars of the square you can follow the line down to Fomalhaut. Bear in mind that Fomalhaut is only visible from southern parts of the UK for a few months of the year and will be very near the horizon.

 

Questions

Explain how stars are labelled in a constellation

Animation
The Plough (Ursa Major)
Orion
Pegasus
Links