How to Identify the Visible Planets

Buy the Farmer’s Almanac. Each edition of this booklet tells you where the visible planets are going to be in the sky each year. The planets travel in orbits that bring them through a series of a dozen constellations, called the Zodiac constellations. Knowing these constellations is the key to viewing the planets. For instance, if the Almanac tells you that Jupiter will spend the entire year within the boundaries of the constellation Virgo, you only need find Virgo in the sky to know that the bright “star” in it is actually the planet Jupiter. A star chart will help you identify the constellations and make finding the planets easier.

Watch for Mercury around the sun. Due to its close proximity to the Sun, Mercury is always hard to see. It is, depending on when it rises, what is called a “morning star” or an “evening star.” It will always be quite low on the horizon and never be visible long past sunrise or past sunset. Your best shot to see Mercury is less than an hour before sunrise when it is a “morning star” and you are able to identify whichever constellation it will be in. It can be easily distinguished from the surrounding stars because of its brightness.

Look for Venus just after sunset and right before sunrise. The second planet, being inside of the Earth’s orbit like Mercury is, also is never out too late. It is brilliant, with only the Sun and the Moon being brighter. Once you find out what constellation Venus is in, and if it is a morning or evening star, finding Venus will not be hard at all.

Gaze at the red planet Mars. This planet has an unmistakable red hue to it. Mars is not as bright as Venus but it can seem to increase in luminosity as it gets nearer to Earth in its orbit. Mars is the first of the “outer planets”, those with orbits further from the Sun than Earth’s. As such it takes longer to make the trip and will seem to be in a constellation much longer than the inner planets.

Watch for a brilliant, giant Jupiter. The size of this planet dwarfs everything else in the solar system except for the Sun. It is very bright, but not as brilliant as Venus. Jupiter takes much longer than Mars to traverse around the Sun, meaning that once you find it, it will be in the same constellation of the Zodiac for the entire year.

Survey Saturn, especially with a telescope. The ringed planet is the last of the outer planets that you can discern with the naked eye. It is not as bright as Mars or Jupiter but can easily be seen. Saturn also takes a long time to make it around the Sun, so it will be in the same star group for quite a while. Referring to your Almanac, learn where it will be and then look for it. If you have a small telescope, it will reveal the fabulous rings that surround this frozen world. Saturn will have a yellowish tint to it to the naked eye.

Realize that stars twinkle, but planets don’t. The light from the planets does not twinkle. The light from the far away stars does. Knowing the colors that some of the planets are, and the various degrees of brightness they possess, will aid you greatly in identifying them. If you see a planet late at night, it will be either Mars, Jupiter, or Saturn; Mercury and Venus always set early.