The sun, moon, and planets move along the same path in the sky called the “ecliptic” which passes through the 12 zodiac constellations. The easiest way to locate the five bright planets, Mercury, Venus, Mars, Jupiter, and Saturn is to look for bright “stars” that are “out of place” near the ecliptic.
Each Planet Locator chart, which can be printed for the given year, has a star map showing the zodiac constellations at the top with the ecliptic running horizontally through the center. Click on the toggle below to access .pdf copies of Planet Locator charts for the years 2011-2021.
The curves running down the page indicate the motions of the sun and five bright planets throughout the year. Each curve is identified by a large dot near the top of the chart. Look in the margin to the right of each dot to identify the planet. Dates are indicated in the left margin. Practice tracing the curve for each planet from the top to the bottom of the chart. When a curve runs off one edge it wraps around and continues from the opposite edge.
To locate a planet among the stars, identify the curve for the planet and trace down the page until you cross the horizontal line for the current date. From that point move straight up the page to the point directly above it on the ecliptic. The planet will be on or near the ecliptic at that point. If you need help locating the constellations in the sky, use The Night Sky star dial.
The heavy solid diagonal line represents the sun. The heavy dashed diagonal line is the point 180° around from the sun in the sky, called “opposition.” The area on the chart to the right of opposition and to the left of the sun is the evening sky, visible at sunset. The area to the left of opposition and to the right of the sun is the morning sky, visible at sunrise. Throughout the night the stars set in the west and rise in the east making a smooth transition between the evening and morning sky.
Each planet has its own characteristics. The inner planets, Mercury and Venus, never stray far from the sun, so they are visible only shortly after sunset or shortly before sunrise. Venus is always the brightest planet, whenever it is in the sky. Mercury is fairly bright, but since it is so close to the sun it must usually be seen in twilight, making it hard to see. Look for opportunities to view it when it is farthest from the sun. Mars is best observed when it is near opposition. At that time it comes closest to the earth, appears largest in a telescope, and is at its brightest. Jupiter and Saturn are also largest and brightest near opposition, but their variation is less extreme. Color can also help you distinguish the planets. Venus is brilliant white, Jupiter is bluish-white, Mars is red-orange, and Saturn is a pale yellow.
[The Planet Locator charts were computer generated using the program Planet Tracker.]