A private observatory is to be opened to the public to raise money for charity.
The Duke of Northumberland has given permission to Alnwick Lions to open Ratcheugh Observatory in aid of Alnwick Stroke Club.
It will be open for one day only on Sunday, July 7, from 10am to 3pm.
Admission will be free, but donations will be welcome in aid of the charity.
The observatory is on the top of a whinstone crag about two miles north-east of Alnwick.
It is a gothic-style Victorian Folly and was designed by Robert Adam and built by John Bell, of Durham, for Hugh, 1st Duke of Northumberland, in the mid-18th century.
It is believed that it was intended as a picnic spot for him and his wife, the Duchess Elizabeth, to view his estates to the Cheviots in the north and seawards and south Northumberland on the east.
It consists of a rough stone building with flat roofs to the tower and welsh slate on the pent-roof part of the south tower.
The tower has an open base and on the first floor has a viewing room, which will be open during the day, with 12-pane sash windows that offer magnificent views in all directions.
The 2nd Duke later added a small cottage at the southern end for a keeper and it is still occupied.
To the east of the observatory is a point-to-point racecourse that is regularly used.
Parking will be free at the racecourse with a short walk up the hill to the observatory.