Place the mirror diagonal (usually a 90-degree device) into the telescope's
focuser, then place the 20mm eyepiece into the other end of the mirror
diagonal. This way you will be looking down into the eyepiece.



This will probably confuse the poster more than anything else... according to
the model number he gave, the telescope is a 114mm reflector, not a refractor.
There will be no external 90 degree diagonal to insert.