The constellation Perseus, the Rescuer or Hero, contains some wonderful celestial objects! It can be found directly overhead at 8pm early in the month and at 7pm late in the month. Using your fist which measures 10 degrees when held outstretched, how tall and wide is the constellation? Measure from head star Eta (n) to the two stars just below Algol to determine the height and Algol to bright star east of it to determine the width. You should measure ~15 degrees tall and a bit under 10 degrees wide. The constellation looks small on the Sky Map but is sizable when you’re looking at it under the stars!

Visual Challenge 1: Catch the Eclipsing star!

Algol, the demon star, with the two stars just below it represent the head of Medusa, the demon that Perseus killed and used to save Andromeda from Cetus the sea monster.  Algol is a variable star which dims from magnitude 2.1 to 3.4 for about 10hrs every 2 days, 20hrs, and 49min. This is caused by another star orbiting Algol that passes in front of our field of view ‘eclipsing’ Algol thereby reducing its light in our direction. Watch Algol for a few days to get a sense of how bright it normally is at magnitude 2.1 and see if you can see the reduction in brightness to 3.4 on January 9 at 9pm, Jan 12 at 6pm, and/or Jan 29 at 11pm. Compare Algol’s brightness to other stars around to help see the brightness difference when it is being eclipsed. As an FYI, Sky & Telescope has developed an app that helps determine when Algol’s minimum brightness is reached, find it here.

Binocular Challenge 2: Find the Double Cluster!

The Double Cluster is one of the most beautiful pairs of star clusters in the sky! Use the Sky Map to find it above the head of Perseus, Eta (n) Perseus. Can you make out any stars using binoculars? If you can, how many do you see? Examine each star cluster closely, how do they compare? Is one brighter than the other? Are they the same size or different in size? Compare the view through binoculars with a view through a telescope if you have one.

Telescope Challenge 3: Resolve the double star!

Eta (n) Perseus represents the head of the constellation and is just south-south-east of the Double Cluster. It is a double star meaning that it contains two stars that circle one another. Take a look at them through a telescope. Do you see two stars close together? If you only see one star you may need to increase the magnification of your telescope by using a shorter focal length eyepiece. If you see two stars close together that appear different colors you have found them! What colors do you think they are? One source says they are orange and blue, do you seen them as such? Try defocusing the stars a bit, are the star colors more or less apparent?