User`s guide

Adding Your Own Data 169
Package Contents, then open the
“Resources” folder to view the “Sky
Data” folder).
You can open these files with a text editor
and copy and paste orbital elements for
new objects. This would be of use if you
wanted a larger satellite database (for
example) then the version in Starry Night’s
“satellites.txt” file. Our Orbital
Elements page: http://
www.starrynight.com/helpPro/
orbitalelements.shtml may have links to
larger database files. If you do plan to edit
text files directly, make sure you have the
“Automatically check for updates” option
in the
LiveSky->Auto Update Preferences
dialog box unchecked, because the
automatic update will wipe out any data
you have added to these files. Editing
these data files is only recommended if
you want to add a large number of objects.
If you only want to add one or two objects,
consider using the Orbit Editor instead.
Adding Objects 3 (Stars)
More than 16 million stars are included in
Starry Night. However, for some
observers, this will not be enough! If you
are using a CCD camera to capture images
of the night sky, you will be able to take
images with stars that are dimmer than the
dimmest stars in Starry Night (the
dimmest stars are about magnitude 14.5).
For this reason, Starry Night includes
online access to the USNO star catalogue,
a database of 500 million stars, as dim as
21th magnitude. The entire database
would occupy about 15 compact discs, so
Starry Night allows you to download data
for only the region of sky that you are
interested in.
Downloading stars from the online star
database works in this manner:
1 Centre on the area of sky you are
interested in and zoom in. You need to
select a relatively small section of the
sky (i.e. a small field of view).
Otherwise, the star file would be too
large to easily download.
2 Choose LiveSky->Download Stars
Now from the main menu. Starry Night
will begin downloading the appropriate
star file. Each file will vary in size from
about 100 kilobytes to 1.5 megabytes.
Once the file is downloaded, you will
see the new stars on your screen. The
downloaded star files are now a
permanent part of your database, and
will be present every time you run
Starry Night in the future.
Automatic Star Downloads: If you choose
LiveSky->Automatic Star Downloads
from the main menu, Starry Night will
automatically download the appropriate
star data files from the Internet whenever
you zoom in to a small enough field of
view. Only select this option if you have a
fast connection to the Internet while you
are running Starry Night!
Deleting Downloaded Star Data: Starry
Night saves all star data that you have
downloaded from the Internet on your
hard drive, so the stars will be present
every time you run the program (you do