Ulugh Beg was a strange kind of ruler. He was Timur's grandson, governor of Samarkand and then the whole realm, but his heart lay with the stars, and around 1420 he built an observatory on a hill north-east of the city that was among the finest in the world. The principal instrument was a gigantic meridian arc, a curved track set into a trench, with a radius of some forty metres, which let his astronomers measure the positions of stars with remarkable accuracy. The star catalogue they compiled, the Zij-i-Sultani, stayed a standard reference for over two centuries, and it corrected many errors in Ptolemy's.
The building itself was destroyed after Ulugh Beg was killed in 1449, probably on the orders of his own son, since religious conservatives resented a scientist king. It vanished from sight until a Russian archaeologist, Vasily Vyatkin, located the buried arc in 1908. What you see today is the lower portion of the great sextant, two curving marble-lined tracks descending into the earth, which you can walk beside. A small museum nearby holds copies of the star charts, instruments and portraits.
The ride up is a short one from the centre, along streets that climb gently to the hilltop of Chupan-Ata. Tarmac is good, traffic moderate, and there is parking by the museum. It is not a ride in the sporting sense, but the view of the city and the Zeravshan plain is lovely, particularly on a clear late afternoon when the Turkestan range shows its snow. Spring and autumn are the best seasons, while summer middays can bake the hilltop.
Samarkand has everything you need, from fuel stations to restaurants. The tea houses nearby serve plov and strong green tea, and in the old town you will find round bread and sweets. The site charges a modest entry fee and keeps limited hours, so check before you go, and bring a hat, since there is little shade on the hill.