Home >> Science & Nature >> Astronomy

How to Locate Planets in the Night Sky

The night sky provides star-gazers a wonderful opportunity to view planets and other celestial objects. Locating planets in the starry evening sky depends on a planet̵6;s right ascension and declination angle, the observer̵7;s latitude and longitude coordinates, and the planet̵7;s position near a constellation. The planets orbit the Sun, and thus are much closer to Earth than the stars. As a result, the planets appear to move inside nearby constellations--allowing astronomers and fellow star-gazers to better identify their location. Familiarizing yourself with such information can help properly locate a planet during the nighttime hours.

Things You'll Need

Computer
Internet access
Printer

Instructions

- 1
  Keep in mind that not all planets will be visible during the evening hours for certain months. According to Martin J. Powell of "The Naked Eye Planets," Mercury will not be seen at all during the evening hours for the year 2010 and the planet Uranus will be visible during the evening hours in the months of January, October, November and December 2010. Mercury is the only planet that will not be visible at all in the evening hours for the year 2010.
- 2
  Locate the planet̵7;s current position by your latitude and longitude coordinates. A planet̵7;s position will differ depending on your current location. An Internet-based latitude and longitude planet coordinator such as City Locator (see the Resource section) can help identify each planet̵7;s positioning based on your current location. After submitting the correct information regarding your current city, latitude, and longitude coordinates, click the ̶0;Save City to a Cookie" option to store your planet observation point. Click the ̶0;Information̶1; option in the top left corner and select ̶0;Planets in the Sky.̶1;
- 3
  Review each planet̵7;s information located on the ̶0;Planets in the Sky̶1; web page. Notice the constellations, RA, and Dec positioning for each planet. RA and Dec positions can precisely determine the exact coordinate of a space object. RA, right ascension, is an angle measured eastward when the Sun̵7;s line of motion during the course of one year interconnects with the celestial equator. Dec, or declination angle, is an angle measurement representing how far north or south the object is from the celestial equator.
- 4
  Print out the "Planets in the Sky" web page to assist your nighttime planet location search. The constellation and Ra/Dec coordinates displayed on the "Planets in the Sky" web page will be used to locate each planet̵7;s position on your Constellation sky chart.
- 5
  Go to the Interactive Sky Charts website (see the Resource section). Using the data you obtained in step 4 for Uranus̵7;s current constellation, select the constellation from the Interactive Sky Chart. A constellation map of the nighttime sky will be displayed, and each constellation and its stars will be represented by a blue line.
- 6
  Consult the chart you printed in step 4 and select the constellation near Uranus. As you click the nighttime sky map, RA/Dec positions outlined in green appear as you move the mouse pointer up and down. Move the mouse pointer up or down until the correct Ra/Dec coordinates (from your notes) are displayed on the screen.
- 7
  Remember the position of the mouse pointer on the constellation map. When the Ra/Dec coordinates and correct constellation of each planet match the data you printed, this is where each planet will be visible in the night sky.
- 8
  Familiarize yourself with the data you've gathered to better locate the evening planets and their constellation positioning. When searching for a planet within the area of a constellation, remember that stars twinkle and planets appear as disc-shaped objects in the sky.

Astronomy