Go to Luz-Saint-Sauveur (D921). Head towards Col du Tourmalet, Barèges (D918). After 200 m, turn right towards Astes (D146). At the edge of the village, the road becomes an unpaved track. Leave the forest and continue along this track, which winds through the summer pastures, past beautiful restored barns. At around 1,640 metres, stay on the same side of the track and continue in the same direction at the next left-hand bend. The car park is marked on the OSM map. Take care not to encroach on the track.
(S/E) At this bend, do not descend towards the bridge. Retrace your steps and turn left, passing through and closing an electric fence. Look for the path that remains on the left bank of the Ruisseau de l'Yse. The path is marked on the ground in places. Continue climbing along it.
(1) Fork (altitude 1,670 m). Turn right, heading south-east, into the Coueyla de Peyrahitte valley (see practical information). Do not cross the Yse. Follow the cairns. The path is not very well marked on the ground, but it is visible. Climb up this coume, simply following a tiny stream that is not marked on the IGN map. You will arrive at an area overlooking the Aygues Tortes summer pastures and the Peyrahitte hut (the return path is visible).
(2) (1900 m). Head right, due south, following the cairns. The path, clearly marked on the ground, climbs very steeply up the summer pasture. Continue climbing and leave Campanal, altitude 2152, on your right. Go around it, following a path that is clearly marked on the ground and cairned, which turns right, heading due west. From this point, a hut is visible high up, due east. This is your destination.
(3) Fork in the path. Open area below the rock face. Take the left fork, heading south-east. Climb up this clearly visible path, which ascends through the scree (see practical information). Cross a stream (unnamed) and then the Ruisseau de Maucapéra. The path climbs very steeply through scree and an avalanche zone. It then becomes less steep and heads due east towards the hut.
(4) Maucapéra hut (2210 m). This is a very beautiful spot. The hut is small but in very good condition. Continue east towards the reservoir.
(5) Fork in the path, altitude 2216 m. Take the right fork, heading southwest, passing at the foot of the reservoir. The path, well marked on the ground and cairned, climbs up into the summer pasture. Continue towards the large rock face where the lake is located.
(6) Lake Maucapéra (2305 m). This is a beautiful spot where you can take a well-deserved break.
Turn around and descend to the previous fork at altitude 2216.
(5) Continue straight ahead. A yellow marker will help you find your way. The path descends slightly for 300 m, then turns left towards the north-west, descending via numerous hairpin bends. The slope is steep. Simply follow the well-marked path without trying to cut across. The path then turns north, then east. Pass through a flat area (EDF window) with a closed hut.
(7) Fork (altitude 2029) with signposts. Turn left, heading north-west, continuing downhill. The path then heads due north, then north-west towards a hut, clearly visible below on a flat summer pasture area.
(8) Peyrahitte hut (altitude 1,820 m). This is a very beautiful spot, the hut is in very good condition and there are also many marmots.
Continue the descent, heading northwest, along a grassy track. You will arrive at a hut with an enclosure (Le Pla Grand). Turn completely left, southeast, continuing down this grassy track. Cross the concrete bridge over the Ruisseau de l'Yse, at altitude 1574, and you will return to the car park (S/E).