An astronomical clock is one that shows the positions of astronomical bodies like the sun and moon with the passage of time. There is a big one, on the side of a building, in Prague, Czech Republic that has been ticking since the 1400s. It is part of Czech national heritage.
The Czech Mint produces all sorts of beautiful coins for collectors, and this is one of them. These have been produced in the last few years.
The value of these medals depends on their metallic composition. As far as we know (check with the mint to find out for sure), the astronomical clock medals are made of either brass or silver. There is a possibility that the silver ones are only silver plated, rather than solid silver, but we do not know for sure.
BRASS OR SILVER PLATE:
worn: less than $1 US dollar approximate catalog value
average circulated: $1
well preserved: $2
fully uncirculated: $5
worn: $20 US dollar approximate catalog value
average circulated: $25
well preserved: $30
fully uncirculated: $40