Go to Caussols and park in the town hall car park or on the grass verge to the right of marker 30.
The hike starts at marker 30.
(S/E) From this marker, take theGR®4via the Chemin de l'Église, then the Chemin de Notre-Dame de Calern. The road gives way to a stony path heading north-west.
(1) The path turns north-east and runs alongside various fences before arriving at the foot of a rocky outcrop, among many spectacular rocks.
(2) On the left, look for a cairn and a red and whiteGR® exit cross. Take this hairpin bend path on the left. After about thirty metres, look for a hairpin bend path on the right, marked by a small cairn with a red brick. Take this path to arrive almost immediately at the entrance to the oratory, marked at the top by a white metal cross and finally visible between the bushes.
(3) After a break to visit this cave chapel, return to the GR®.
(2) Continue for about a hundred metres, then look for a series of cairns on the left that climb up to the plateau. Take this climb until you reach the track on the plateau.
(4) Take this track on the left and walk along a small wood on your left.
(5) Turn left again to reach the ridge of the Calern Plateau, on the northern slope of Caussols, and continue to the summit.
(6) For the return journey, after continuing for a hundred metres or so after the summit, on the ridge, take a path on the right, initially marked by wheel tracks, which joins a track further down that you take eastwards to the junction you passed on the way up.
(5) Continue straight ahead, following the same route as on the way up.
(4) Continue straight ahead until the next fork (marker 50), where a path leads straight to the observatory.
(7) Take a sharp right turn.
(2) Continue straight ahead and follow the same route as on the way there until you reach the car park (S/E).
