User`s guide

Adding Your Own Data 167
that are about 600 pixels long by 300
pixels high.
Whatever picture you do use, its width is
wrapped around the planet, and the height
of it will go from pole to pole. Because
Starry Night maps the image on a sphere,
your image will be distorted in the
northern and southern latitudes. Keep the
important parts of your image near the
“equator”. For examples, look at the
default images of the planets. These
images can give you an idea of how an
object’s map relates to the appearance of
the planet.
Seams on objects: If you have an image-
editing program, such as Adobe
Photoshop, you can adjust your images so
that the seam (where the end of the
pictures meet when wrapped on a planet)
is minimized or invisible. Select one end
of the picture (for example, the right third
of the image), and cut it. Then slide the
remaining two-thirds of the image all the
way over to the right. Paste in the first
piece, and position it so that it is now the
left side of the image. You should now
have an obvious seam where the two
pieces are joined. At this point, you can
use the image-editing program to clean up
the seam, blending the two sides together
so that the join is less obvious. Now select
the entire picture and copy it. Then, using
the Orbit Editor, paste it into your Starry
Night object. The place on the object
where the two sides of the image meet
should now be seamless.
Other Settings: Using the sliders and data
boxes in this tab, you can enter
information about your new planet’s
rotation rate, pole positions, diameter and
absolute magnitude.
Meridian Position: Sets the position of the
object’s prime meridian, in J2000
equatorial co-ordinates.
Rotation Rate: Sets the rate at which the
new object spins on its axis.
Tidal Lock With Parent: Over time, many
objects in the solar system become
gravitationally locked, that is, they keep
the same face towards their parent at all
times. Our Moon is a good example of this
phenomenon. Clicking this button
automatically locks your object by setting
its rotation to match its orbital period.
Pole RA: Sets the right ascension of the
object’s north pole, in reference to the
Equatorial co-ordinate system.
Pole Dec: Sets the declination of the
object’s north pole, in reference to the
Equatorial co-ordinate system.
Diameter: Sets the diameter of your new
object, measured in kilometres.
Note: Comet tail lengths are determined
as a result of both absolute magnitude and
size of the comet nucleus (diameter).
Absolute Magnitude: Sets the inherent
brightness of your object.
Saving Changes: Once you have entered
all of the data for your new object, close