Thousands of pounds of equipment was stolen during a break-in at a Wiggonholt nature reserve on Tuesday (June 24).
Police received a report at around 10pm that alarms were sounding and the entrance to the shop had been forced.
Cabinets were broken into and binoculars and jackets were among the items stolen.
Police are appealing for witnesses.
Anyone who saw anything suspicious in the area can contact police by calling 101 or sending an email to 101@sussex.pnn.police.uk quoting serial 1737 of 24/6.