London, April 26 -- A rare 17th century brass astrolabe, a hand-held astronomical supercomputer, from Maharani Gayatri Devi of Jaipur's collection is set to fetch millions at a Sotheby's auction in London next week. The astrolabe, which forms the centrepiece of the auction house's 'Arts of the Islamic World and India' sale on Wednesday, went on display this weekend and is estimated to fetch between 1.5 and 2.5 million pounds. Dating to 1612, it is believed to be the largest of its kind and was created by two brothers for Aqa Afzal, who at the time was overseeing the administration of Lahore under Jahangir. The intricate device was part of the royal collection of Maharaja Sawai Man Singh 2 and by descent his wife Gayatri Devi, Rajmata of Jai...