The star Atlas is by far the most useful tool to have with you under the night sky. An atlas is a collection of star
charts and the chart is your key to what you see in the night sky.
At night all the stars move together like a big sheet overhead. As we look up the stars remain fixed in place in
relationship to one another yet altogether the sky "sheet" continues to progress from east to west. We only
notice the movement if we stay out for a long period of time. This movement is due to the earths rotation. As
the earth rotates during the day we observe this motion by the suns position in the sky. By midday the sun is
high in the sky. Once again its really the earth rotating (spinning) in place that causes this star sheet or the sun
to slowly move overhead. This imaginary "sheet" of stars is best pictured as a star globe. Our minds see imaginary patterns when look up at the stars. The 88 constellations is our method of grouping the stars with
agreed upon figures. We can then place these constellations in the star globe and get a feel for where everything is. The star globe can be given coordinates just like our earth globe, with each star having an exact
position in the sky.
The planishere is a portion of this star globe that is projected flat on a sheet that we can hand hold. Depending
on which hemisphere you live in should get the planishere that's for you latitude. You can then use it to determine what part of the sky you will be observing on any particular time and night.
In a matter of moments the planishere shows which constellations are in view. Now its a simple matter of
opening your star chart to the constellation of choice. The chart will show all the stars in that constellation down
to a certain magnitude. The star names, types and exact positions can be found on the chart. Deep sky objects,
clusters, galaxies, nebula will be plotted for easy locating. Using these charts takes practice. Go out under the
sky with chart in hand. Take time to visual go back and forth between chart and sky and begin to identify stars and objects.
Use the chart just like an earth atlas, finding the longitude and latitude along the side. If you have setting
circles on you telescope you can slew the scope to any object by using the coordinates shown in your star atlas. Without setting circles you can use the chart to help you star-hop to near by objects of interest.