OPC and Panels

The Observing Programmes Committee (OPC) is the body in charge of reviewing, evaluating on scientific merit, and ranking the proposals submitted in response to a call for the use of ESO observing facilities of the La Silla Paranal Observatory and thereby advise the Director General on the distribution of observing time, taking account of ESO's scientific policy. The OPC is assisted in its task by Expert Panels covering specific scientific areas.

The committee’s size has gradually adapted to the growing number of proposals. After the inauguration of the La Silla Observatory (March 25th, 1969) the Scientific  Programmes Committee, then chaired by B. Stroemgren and composed by six members, reviewed the first proposals. In 1971 the committee changed its name to Observing Programmes Committee, which was kept ever since. The OPC included six members until 1981, after which its size was increased to eight. This configuration remained unchanged until 1988, when for the first time the OPC members were flanked by a few so-called members at large. In 1993, when the submission rate exceeded 500 proposals per semester, ESO had to re-evaluate the case. Sub-panels (with six members each) were introduced for the first time, and the meeting was split into two parts, the panel meetings (attended by 34 reviewers) and the OPC-proper meeting (attended by 12 OPC members, including eight national representatives and four members-at-large). This configuration remained unchanged until 2000, when the Committee was significantly restructured, with the introduction of the four categories currently in use, each comprising two sub-panels with six members each, for a total of 48 scientist, plus the OPC Chair. The situation became again critical in 2004-2006, when the Nominating Committee was introduced for the first time. In P78 C and D categories went through a first change, increasing their number of panels from 2 to 3, for a total of 60 members. This was quickly judged not to be sufficient, and in 2007 the number of sub-panels was further increased to four, bringing the composition to 72 members. Finally, following the evolution, one extra sub-panel was added in P85, increasing the total number of members to 78 (plus the OPC Chair). This configuration is still in place.

In the current implementation, the OPC is composed by 16 members plus the OPC Chair. The OPC is assisted by 13 Expert Panels. Each panel is composed by 6 members, which include the Panel Chair, who is also OPC member. To balance the number of representatives for each of the science categories, some panels include a co-Chair, who is also member of the OPC.

A general description of the time allocation process in place at ESO until P109 is provided here.

Guidelines and reference documents concerning the OPC and Panel activities are listed below.


As of P110, Distributed Peer Review has been introduced at ESO to decrease the load on the OPC and Panels.