The workshop will take place at the Observatoire de Lyon (9 avenue Charles André, 69561 Saint Genis Laval).
There are a few ways to reach the Observatory:
A first solution is to take bus C10 at place Bellecour. Get off the bus at the stop "Saint-Genis Centre", and enjoy a 10 minutes stroll up to the observatory, as indicated on the map below. Bus C10 is frequent enough (one every 8-10 minutes).
A second solution is to take bus 101 at Perrache (just above the metro station, within the Perrache station). Then, get off at the stop "Observatoire", and enjoy a 3 minutes walk to the observatory (starting from point 2 on the map above). Bus 101 is not as frequent as bus C10 (about a couple per hour). Its time table can be found here
Bellow is a map of the area of Place Bellecour and Perrache indicating the bus stops (it takes about 15 minutes walk from Perrache to Bellecour).