Understanding the Night Sky


If you are willing to brave to chill and go outside on a clear winter evening, then you are likely to see the jewel-like stars of Orion,

see the Astronomy Picture of the Day Site for more information about this image

as well as the Face of Taurus, and the beautiful blue stars of the Seven Sisters, or Pleades Star Cluster.
The Pleades at sunset

Click on the image for full view

and explanation from the photographer


On the other hand, warm summer evenings are perfect for observing the bright stars of Scorpio and Sagittarius

The Stars of Scorpio near sunset

Scorpius--above (at it appears near sunset) and below (with lines to help you see the scorpion!)

Scorpio with Constellation lines drawn in

Sagittarius with Milky Way in Background

Sagittarius above and below(with lines drawn in)

Sagittarius with constellation lines and star names drawn in

At times, however, you will notice a very bright visitor, one of which often outshines every other star in the sky...

Mars between Sagittarius and Scorpio in June 2001--southwest just after sunset


Of course, if you watch this part of the sky for a while, you'll see that the visitor (Mars in this case) moves relative to the stars(here in Scorpius and Sagittarius). If nothing else, this proves an important principle in astronomy, and a key to the development of modern astronomy: The Planets move in the sky relative to one another and the "fixed" stars. You certainly won't notice this motion in one night, or even in a week but it you keep looking up, you will certainly see Mars move along the Ecliptic (the path of the planets and sun across the celestial sphere). So for now, take time each night to stop and stare at the stars and planets, the astronomical equivalent of botany's "Stop and Smell the Roses..."

Better still, check out the real "stars" of the night sky this month, in this sky chart, courtesy of Sky and Telescope Magazine. Not only is it interesting, but you are required to gain familiarity with the night sky in this class!

Below, you can see how Venus appeared in the constellation Virgo, near sunset in late August, 2002. Usually, when Venus is visible, its the brightest star-like object in the night sky. Question: why is Venus only seen near sunrise or sunset?

Right now the real "star" of the night sky is Mars!



If you are interested in more constellations , check out these (optional!)constellation photos from the Northern hemisphere (the photos and sketches above are courtesy of this site). If you want to know where to look, then try out Sky and Telescopes The Sky Tonight link found on the learning resource page.

While you're at it here a question for next time: How can use constellations to help you find the location of Polaris, the North Star, as well as simply finding your way North? .

image of star trails over rocky terrain

First lets see how you spot Polaris in the night sky:

note the two stars in the "pot" of the big dipper that are lined up with polaris (the green star at the end of the handle of the little dipper). These are the "pointer sisters" and they point right at the North Celestial Pole..now .you can always find your way North on a clear night when the dipper is visible!