22 • Telescope Basics
T E L E S C O P E B A S I C S
Once your telescope is fully assembled, you are ready for your first look. This
section deals with some of the basics of telescope operation.
The image orientation changes depending on how the eyepiece is inserted into
the telescope. When using the star diagonal, the image is right-side-up, but
reversed from left-to-right (i.e., reverted). If inserting the eyepiece directly into
the visual back (i.e., without the star diagonal), the image is upside-down and
reversed from left-to-right (i.e., inverted). This is normal for the Schmidt-
Cassegrain design and applies to the telescope’s finder as well.
Image Orientation
Figure 3-1
These simplified drawings of the planet Jupiter illustrate the different image orienta-
tions obtained when using various viewing configurations.
