Leading a Waymark party based at Pralognan. From Pont de la Peche. We followed GR 55 to Ritort and then turned off on the path signposted to Col d'Aussois. The path climbs up steeply and then more gently. The route ascends over a rocky buff, followed by a long gulley up to Col d'Aussois. There was extensive névé on the approach to the col. Although some people ascended the rocky slopes to the right, I and the rest of my party ascended the névé. In my opinion ascending the névé is best (as long as it is in good condition). One member stayed at the col while everybody else ascended to the summit of Pointe de l'Observatoire. This involved a simple scramble. We descended to the col and back down the névé. The weather was excellent so we had good views from the summit, including Mont Blanc.