University of Michigan - Department of Astronomy


Reading a Star Chart

Any star is enough [to be a guide] if you know what star it is.

-- William Stafford



The stars visible to you vary by your location and the time of night and time of year (see one of the celestial sphere activities.) Because of this, star charts are printed for a specific latitude (often a specific city, though the chart applies to any other city with a similar latitude), date and time. A chart printed for within 20º of your latitude is sufficient for most observers.

Many weather sites provide free star charts, such as the weather underground Abrams Planetarium at Michigan State University publishes a very nice sky calendar (you can see it on many of the bulletin boards in the department). More information on it is at Sky and Telescope and Astronomy magazines both include star charts. Additionally, there are online sites like, Your Sky, and that provide printable star charts for free online.

Part 1: Looking at the Chart

Begin by looking at the star chart.  Find north, south, east, and west on the star chart. Note that the constellations are labeled with their abbreviation. You may need a constellation list or another chart to get the full names and see what seasons they belong to. Answer the questions below.

  1. Why are east and west reversed (hint: think about how you'll hold the chart when you're using it)?

  2. What constellation is on the northern horizon?

  3. What constellation is on the southern horizon?

  4. What constellation is rising in the east?

  5. What constellation is setting in the west?

  6. What constellation is near zenith?

  7. What constellation will set in the northwest soon?

  8. What season is the star chart for?

  9. What seasons of constellations are visible?  Does this make sense?  Explain.

Part 2: Using the Chart in the Planetarium

Your instructor will give your group a laser pointer and a constellation or two to find.  Write your constellation(s) here:

(S)he will turn on the stars for Jan 1 and dim the planetarium lights.  Use the star chart to identify your constellation on the dome.  When your instructor calls on your group, use the laser pointer to point our your constellation(s) to the class.

Last modified: 8/12/05

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