Like Mamalluca, the shiny hilltop Observatorio Collowara in Andacollo is built for tourists; no serious interstellar research is conducted here. Two-hour tours run in summer at 9:30pm, 11pm and 12:30am; in winter they are at 8pm and 10:30pm. The facility boasts three viewing platforms and a 40cm telescope – slightly larger than that at Mamalluca. There are also three smaller telescopes available, so you won't have to wait for long.
There are plenty of accommodations in Andacollo, 54km from La Serena and connected by bus (CH$2200, 1½ hours) and colectivo (CH$2800, one hour).