The Yuri Gagarin stamp is the nearest I could find that relates to astronomy at the moment. The stamp was issued to commemorate the 50th anniversary of Gagarin's journey into space but there is - they say - another link with Moldova. It is said that he visited the wine cellars at Cricova, north of Chişinău, and wasn't seen again for 2 days. I don't know whether that was before or after his flight into space. :)
This is a post for Sunday Stamps, run by Viridian. Click on the button to visit her blog and all the other participants.