project
Find Planets in the Sky
Materials
1. Pick Your Planet
Think about which planet you want to find in the night sky. Maybe you heard about the Europa Clipper mission launching to the gas giant Jupiter. Or perhaps Venus’ thick atmosphere makes you curious about this Earth-size planet. Start with one planet, but you can always repeat these steps to find more.
2. Open the Virtual Night Sky
Open a free planetarium or sky charting program. There are lots of options, but these instructions show screenshots from Stellarium. Most programs will require you to follow similar steps.
3. Get the Software Setup
Your sky software may automatically detect your location and date. If not, set those by clicking the location and date boxes. You can also adjust the time to show different times of day or night. If you’re not familiar with 24-hour time format, just subtract 12 from any hour 13 or greater to get the hour after 12 noon.
It can be useful to turn on the azimuthal grid if it isn’t turned on already. This can help you identify where to look in the sky to spot your planet.
4. Set Your View and Find Your Planet
You can click and drag the screen to view different parts of the sky and zoom in and out to get a wider view than you might actually be able to see all at once with your eyes outside.
For finding planets, set your view toward the south (marked by S) and set your zoom so you can see east (marked by E) and west (marked by W). Click the hour arrows to move through the night until you see your planet rise in the east and move west with the night.
Keep in mind during certain times of year some planets may not be visible at night. If they’re on the Sun-side of Earth in the sky, they are only above the horizon during the daytime.
5. Go Outside and Find Your Planet
Make a note of when, which direction, and how high to look for your planet. To help you find which direction to face, remember the Sun rises in the east and sets in the west. When east is to your left and west is to your right, you’re facing south in the northern hemisphere. At the proper time, look for your planet. Venus and Jupiter are the two brightest planets, so they can be easy to find. Saturn is also pretty bright and Mars has a reddish tint that can give you a clue. Mercury is only visible right before or after sunset and always near the horizon, while Uranus requires very dark skies to see without binoculars or a telescope. Neptune is not visible to the unaided eye, but you can still identify where in the sky it is, even if it’s too dim to see.
Image credit: Bill Dunford
6. Use Math to Help You Find Your Planet
If you're familiar with degree measurements, the azimuthal grid can help you find your planet in the sky. The horizon makes up a circle of 360 degrees, with zero degrees to the north and 180 degrees to the south. Looking from the horizon to the sky makes an arc that starts at zero degrees on the ground and reaches 90 degrees when you’re looking straight up. Use the degree markings on the azimuthal grid (usually indicated on the edge of the screen) to approximate how many degrees high your planet is at your planned observing time. You can use this guide to measure approximate degrees in the sky with an outstretched hand.
7. Make Predictions About Planet Locations
From the same place, observe the location of a planet for several nights in a row at the same time. Then make a prediction about where it will appear the next night. Tall objects like trees and power poles can help you describe locations of objects in the sky.
8. Print a Sky Map
If you’ll be away from a computer or mobile device but want a way to see what is up and where, you can print out sky charts. Sky Maps provides monthly sky charts that highlight what you can see. Heavens-Above allows you to customize a sky chart by selecting a viewing location, date, and time.
To use a circular sky chart, hold the map overhead so you can see it while looking up and align north on the map with north in your location. The circular chart is a flattened representation of the spherical sky overhead, so remember objects near the edge of the circle are closer to the horizon than objects in the center of the circle.
Don’t forget to check out the What’s Up video series for monthly updates of things to look for in the night sky!
Image credit: Heavens-above.com