The Orion Pentaprism 90-Degree Diagonal ($199.99US) is a non-inverting, non-reversing 1.25-inch diagonal. Unlike typical star diagonals, the Orion Pentaprism Diagonal does not produce a mirror-reversed image, which can make navigation and referring to star maps difficult while observing with your telescope. But unlike common correct-image diagonals, there is no image […]