Introduction

When is the best time to see the Andromeda Galaxy, known also as M31? What about M42, the Great Nebula in Orion? That depends on several factors. First, where you are on the planet Earth, second, what time of year it is, and third, when you like to do your observing. The best time to see anything through our atmosphere is when the sky object is near the meridian, the imaginary line that runs through the North Pole point in the sky, through the zenith (the point directly overhead), and through the South Pole point in the sky (which will be below the horizon for Northern Hemispherians). Let’s examine these three factors individually.