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How to View Constellations

Constellations are groups of stars that represent fanciful figures imagined by ancient peoples. The International Astronomical Union recognizes 88 constellations, which are defined as bounded areas of the celestial sphere (the apparent sphere of the sky) within which the star patterns are contained. Every visible star is included in a constellation. The stars that make up constellations are usually not physically associated; they appear together because they lie close to the direct line of sight.

Things You'll Need

Sky atlas or sky map, or planisphere
Red flashlight
Compass

Instructions

- 1
  
  The stars appear to move in concentric circles around the celestial poles.
  
  Study your sky atlas or other reference and find the "Big Dipper," an arrangement of seven bright stars in the constellation Ursa Major. The Big Dipper is imposing, and one of the most recognizable star patterns in the northern hemisphere. You can use the Big Dipper as a guide for finding nearby constellations.
- 2
  Observe the closeness of the Big Dipper to the north celestial pole, the northern point on the map where the longitude lines converge. This constellation actually looks like a dipper with a bent handle and squarish bowl. Note its size in relation to other star patterns and constellations, and that the bowl occupies a large area of the sky.
- 3
  Find a place where the sky is dark, away from sources of artificial light. The "light pollution" in urban areas blots out the night sky, making it difficult or impossible to see any but the brightest stars. If you live in or near a large city, hunt for constellations when you are 20 to 30 miles beyond the outskirts.
- 4
  Hold the compass level in front of you. With the aid of the flashlight, turn in the direction of the needle and align yourself until it points straight ahead. You are now facing due north.
- 5
  Look up at the sky, without turning your head away from north, at an angle above the horizon equal to your latitude. For example, if your latitude is 45 degrees north, fix your view halfway between the horizon and the zenith (straight up). Note that the angular distance between the horizon and zenith is 90 degrees.
- 6
  Spot the bright star, Polaris, that appears in view. Polaris is the North Star, the brightest star in the local area, and is half a degree from the north celestial pole.
- 7
  Scan a small circle around Polaris, and then scan in progressively larger circles. The shape of the Big Dipper should quickly become obvious. Note that the two stars forming the front of the bowl are on a line that points almost directly to Polaris.
- 8
  Extend this line by an equal distance past Polaris. Note the prominent arrangement of stars in the shape of a "W." You have found the constellation Cassiopeia, the Queen.

Astronomy