There are several ways to use the Star Finder. The simplest is to tap the
icon in the upper right corner of the screen and pick a star from the
pop-up list. The chart will highlight your choice and zoom in on it.
The Star Finder can also teach you about the constellations. As you page
through the constellations using your handheld computer's scroll button(s),
you will see a picture of each constellation, a brief description,
and a handy visibility chart that shows the best months to
observe this constellation.
If you're interested in the individual stars of a constellation,
tap on them in the picture to see additional information about them:
magnitude, spectral type, distance, rise and set times and current
position in the sky. For the purposes of stargazing, a star's current
position is by far the most useful of all that information.
The current position of a star is shown by the two gauges in the lower right
of the Star Finder screen: azimuth and altitude. The gauge on the left is the
altitude, or the angle of the star's elevation above the horizon.
(If the star is below the horizon, its altitude is negative.)
The gauge on the right is the azimuth, or the star's angle along
the circle of the horizon, starting at 0 degrees (north) and moving clockwise
through 90 degrees (east), 180 degrees (south), 270 degrees (west) back to
360, or 0 degrees.
In our example, you would find Sirius in the sky as follows. Start facing
north, then turn 128 degrees to the right and raise your sight 26 degrees
above the horizon. The bright star you're looking at is Sirius.
Why Can't I See My Constellation?
Sometimes you pick a constellation from the list and the chart shifts
toward it, but nothing seems to be highlighted. This means that your chosen
constellation is too far below the horizon at the moment to appear
even in the farthest corner of the chart. Try using one of the
time steps
- e.g., rise or transit - to bring it into view. Note the time when the
constellation will be visible.