The coin has the shape of a circle, at the front and back sides there's a protruding edging around the circumference. The side surface of the coin is smooth.
At the top there's a relief image of the State Emblem of the Republic of Belarus; in the center of the coin there is an image of a fragment from the work "Ars Magna Lucis et Umbrae" by the German scientist A. Kircher, representing the interaction of celestial bodies; on the right there's a sample, under it - the trademark of the Mint of Poland JSC. In the inscription circle: at the top - REPUBLIC OF BELARUS, at the bottom - the face value of 20 RUBLES and the year of minting.
In the center, there's a stylized image of a clock located on a clock tower in St. Mark's Square in Venice, as well as a relief stylized image of a sagittarius. The inscription on the right in a circle: SAGITTARIUS; below - there's an insert: a transparent capsule with a movable silver element in the form of a sagittarius.