herschelian telescope(n = noun.artifact) off-axis reflector - a reflecting telescope with the mirror slightly tilted to throw the image to the side where it can be viewed;
is a kind of reflecting telescope, reflector

astronomical telescope, cassegrainian telescope, coude telescope, galilean telescope, gregorian telescope, herschelian, hubble space telescope, hubble telescope, maksutov telescope, newtonian telescope, optical telescope, radio telescope, reflecting telescope, refracting telescope, schmidt telescope, solar telescope, telescope, telescope bag, telescope sight, water telescope