Telescopes with star diagonal

Star diagonal

— the presence of a star diagonal in the design or in the set of the telescope.

This accessory is used in combination with lens and mirror-lens telescopes. In such models, the eyepiece is located at the end of the tube and is directed along the optical axis of the telescope; in some situations — for example, when observing objects near the zenith — such an arrangement can be very inconvenient for the observer. The diagonal mirror allows user to direct the eyepiece at an angle to the optical axis, which provides comfort in the situations mentioned. However the image usually turns out to be mirrored (from right to left), however, when observing astronomical objects, this can hardly be called a serious drawback. Star diagonal can be both removable and built-in, it can also be possible to change the angle of rotation of the eyepiece.