Continuing the series ‘Finding Stars and Constellations’
Cassiopeia. This constellation is named after the vain queen Cassiopeia in Greek mythology. The five stars in the constellation appear in the celestial sphere in the shape of the letter W and can be observed in the northern hemisphere and down to 20oS.
Star 5 of Cassiopeia can be located along a line of reference from the Pole Star at an angle of 135o to the line of pointers as the diagram above shows. As Ursa Major revolves around the Pole Star in an anti-clockwise direction, so do the five stars of Cassiopeia but star 5 keeps its position 135o from the line of pointers. The angular distance of star 5 from the Pole Star is 30o or roughly one and a half hand-spans.
The brightest star in the constellation Cassiopeia is Alpha Cassiopeiae otherwise known as Schedir which is a navigation star.
Perseus. This constellation is named after the Greek mythological hero Perseus. If a line is drawn from star 3 to star 4 of Cassiopeia, it will point almost directly towards star 3 of the constellation Perseus at about one hand-span as shown in the diagram.
Perseus can be easily seen in the northern hemisphere during the winter months and in the northern areas of the southern hemisphere north of 35oS. during the summer. Even though Perseus’ stars are bright relative to other constellations, Mirfak is its only navigation star.
Andromeda. The diagram shows that, if the line from the Pole Star to star 5 of Cassiopeia is extended, it will point to star 3 of Andromeda at about one and a half hand-spans. The diagram also shows that the 4 primary stars of the constellation Andromeda, when lined up, point to star 1 of Perseus.
The constellation Andromeda is named after Andromeda, the wife of Perseus in Greek Mythology and can be seen in the northern hemisphere and in the southern hemisphere as far south as 40oS.
The brightest star in Andromeda is Alpheratz which is a navigation star.
Watch out for the next post in this series which will be issued shortly.