A single sheet European astrolabe produced during the 15th century is estimated to make £80,000-120,000 ($127,331-190,997) ahead of a sale at Bonhams.
The lot will lead the Scientific and Mechanical Musical Instruments and Calculators auction in London on November 4.
Astrolabes date as far back as 150 BC and were used for a variety of applications, including navigation and surveying.
Each side appears to have been engraved by two separate hands, one in the 15th and the other in the 16th century. One is numbered and notated in gothic script while the other is engraved in italic.
The origin is difficult to determine, although it's thought to have been made in Europe but based on a design by Muslin astronomer Ibn as-Sarraj.
It bears a strong similarity to work by English manufacturer Henry Cole.
Bonhams comments: "Despite being incomplete it supplies important evidence for the continuity in use, by recycling, of late medieval instruments in Early Modern Europe, and is highly significant as an hitherto unknown document for the presence of a rare and unusual form of universal astrolabe in late Medieval Europe and thus its transmission from Islam."
A German SG-41 "Schlusselgerat" coding machine built in around 1944 is valued at up to £30,000 ($47,830).
It was intended as a replacement for the Enigma machine, although it was never implemented.
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