Standard Proposals
LCO's year is subdivided into two observing semesters, each 6 months long. Standard proposals from astronomers affiliated with LCO's Science Collaboration institutions are accepted every semester. The Science Collaboration partners allocate their shares of time according to their own TAC procedures. They may elect to assign some of their time to Key Projects (see below) with which they are involved.
For the Open Access program (supported by the Heising-Simons Foundation for the 2025A-2028B semesters), proposals may be submitted from any member of the astronomical community: faculty, students, post-docs, research scientists, observatory staff, etc.
For LCO's own share of observing time, standard proposals are accepted from astronomers affiliated with LCO's non-guaranteed-time partners: the University of California at Santa Barbara and IPAC at Caltech. Proposals are also accepted from members of LCO's scientific family: current staff, astronomers who were postdocs at LCO in the last 5 years, astronomers who were graduate students at LCO in the last 3 years, and astronomers who served on our advisory and allocation committees in the last 2 years.
A Time Allocation Committee (TAC) returns a ranked list of proposals plus advice on scheduling. The Director assigns time to successful proposals and contacts the authors. Time allocations to standard proposals are for a single semester only.
The most recent call for standard proposals is posted in the Announcement section of the website.
Key Project Proposals
Proposals for Key Projects are accepted every three years. Key Projects are large, coherent observing programs designed to take maximum advantage of the unique attributes of the LCO network to address important astrophysical problems. Key Projects are expected to have a duration of up to three years. Astronomers affiliated with LCO or any of LCO's Science Collaboration institutions may submit proposals for Key Projects.
Key Projects generally acquire several hundred (perhaps several thousand) hours of observations, and large project teams are assembled to carry these out. These are LCO's premier science programs. Because LCO is contributing large amounts of telescope time to support Key Projects, collaborators on proposing teams from other institutions are required to commit significant resources to the effort. Such resources could be access to other facilities, or additional time on the LCO network from their own institution, or computing resources, or scientist time.
LCO is currently supporting seven Key Projects.
Director's Discretionary Time Proposals
LCO does not allocate all (expected) observing hours to TAC-reviewed science projects. Some hours are held in reserve and may be allocated at the discretion of LCO's director. These discretionary hours are intended for observations of unforeseen targets-of-opportunity. Astronomers affiliated with an institution in LCO's Science Collaboration and investigators in the US Community (through the Heising-Simons-funded Open Access time) are eligible to submit proposals for discretionary time. However, the proposals must clearly justify why the observations must be carried out more immediately than the normal proposal/review cycle allows. Proposals for discretionary time may be submitted at any time, but the time expires at the conclusion of the current semester. A standard proposal must be submitted (and approved) to sustain observations for the same science project into the new semester.
Notification of Review Decision
Standard and Key Project proposals are reviewed by a Time Allocation Committee (TAC) panel whose members are selected from the astronomical community and are not employed by LCO. Proposals recommended for scheduling by the TAC are awarded time by LCO's director. PIs are notified of a standard proposal's acceptance approximately 6 weeks before the start of the semester. Proposals for discretionary time are reviewed by LCO's director only. Notices of acceptance are issued as quickly as possible, but typically in less than one week.