|
An attachment for a small telescope,
containing a small plane mirror or prism, used to turn through
a right angle the beam of light in the telescope and the direction
of the draw-tube into which the eyepiece
is inserted. Use of a diagonal may be helpful when the visual user of a small amateur telescope
would have difficulty accessing the eyepiece in its normal tube. However, there is some loss of
light when a further optical element is introduced, and there may also be loss of image quality.
The image in a diagonal is reversed right-to-left.
|