Previous page  Page 3   Next page    Table of Contents 

the main menu and select "Glossary".  The Help system is a "hypertext"
system:  you can click on any term shown in blue to get the definition
for that term. To print the help information, save it to a file,  go
back to the glossary, or go back to the previous item, just click the
appropriate help menu item.

   In most places in Guide,  you can hit F1 to get a few paragraphs
describing the dialog or control you are currently using.  Many
dialogs have a '?' button that gets the same information.

3:  WHAT GUIDE IS SHOWING YOU       

   The first time you start Guide, a large area of the sky appears.  It
shows roughly what you would see looking at the Big Dipper with the
unaided eye.  The stars are of different sizes, corresponding to how
bright they appear to be from Earth.  There are also some lines which
the sky does not show, and a block of text.  For example, a set of
green lines connect the stars of the Big Dipper.  These "constellation
lines" join together the major stars within a constellation.  They
have no real astronomical significance,  but help you to remember where
stars and constellations are.
                                                 
   The constellations are separated by orange lines,  known as
constellation boundaries. The entire sky was officially subdivided into
88 constellations in 1930. The borders are like those of the Western
United States;  they run the equivalent of east-west and north-south.
They provide a further frame of reference.

   Each constellation has a three-letter label shown in light blue
somewhere within the constellation bounds. For the Big Dipper it is
"UMa": "Ursa Major" or "The Great Bear".  (The Great Bear is usually
shown with the Dipper serving as its tail. Seeing the rest of the
Bear,  or of most constellation figures, requires some imagination.)
                                                   
   Many of the stars have Greek letters attached to them.  This shows
the most common way of naming the brighter stars: letter plus
constellation name. Thus, the star at the end of the tail of the
Great Bear can be called Eta Ursae Majoris.  (The added "is" is a
Latin version of "belongs to.") These letters are called Bayer
letters, after the astronomer who first assigned them.  Usually,  but
not always, they are in order of brightness within a constellation,
i.e., Alpha is brighter than Beta which is brighter than Gamma.

   In Guide,  there is a fairly general way to adjust the display of
any of these objects when they appear on-screen.  If,  for example,
you found the constellation lines to be objectionable and wanted to
get rid of them,  or change their color,  you would click on one of
them with the right mouse button.  You will immediately get a short
bit of information about the object you clicked on (which can help in
"what in the world is _this_?" situations.)  But the dialog box with
that information will also have a "Display" button;  clicking on this

 Previous page  Page 3   Next page    Table of Contents