Telescopium Herschelii (Latin for Herschel's telescope), also formerly known as Tubus Hershelli Major, is a former constellation in the northern celestial hemisphere. Maximilian Hell established it in 1789 to honour Sir William Herschel's discovery of the planet Uranus. It fell out of use by the end of the 19th century. θ Geminorum at apparent magnitude 4.8 was the constellation's brightest star.