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Astronomers Must Compete for Telescope Time

by Richard Wainscoat

Over 90 IfA astronomers and graduate students are among those competing for the UH's 10-15 percent of the observing time on Mauna Kea telescopes. Photo by Richard Wainscoat.

There is a limited amount of observing time on the big telescopes on Mauna Kea, and astronomers compete strongly for it. UH astronomers have access to between 10 and 15 percent of the observing time on each of the Mauna Kea telescopes. For all telescopes except the NASA Infrared Telescope Facility, the IfA director allocates the UH observing time based on the recommendations of the UH Time Allocation Committee (TAC). Since the IRTF is a national telescope, it has its own TAC that includes scientists from throughout the United States.

Most Mauna Kea telescopes are scheduled using common six-month semesters: February-July and August-January. Twice each year (with deadlines on April 1 and October 1), UH scientists—including astronomers at IfA and UH Hilo, and planetary geoscientists at the Hawaii Institute of Geophysics and Planetology—write comprehensive research proposals detailing all the observing time they are requesting during the upcoming semester. Astronomers prioritize their proposed research projects to assist the TAC's decision because the total time requested by UH scientists often far exceeds the supply.

The TAC is composed of nine UH faculty members, one postdoctoral research fellow, and one graduate student. Most members of the committee are active observational astronomers who regularly use the telescopes on Mauna Kea. Their areas of expertise span a broad range of nighttime astronomy, including the solar system, stars, star formation, extragalactic astronomy, and cosmology. At present, two of the TAC members are located in Hilo. One is a UH Hilo faculty member, and the other is an IfA faculty member located in Hilo. The Hilo committee members sometimes fly to Honolulu for meetings, but recently they have found it more convenient to attend via video-conferencing equipment.

The TAC must recommend how best to use our precious observing time. This task is often formidable, with the requests for observing time far exceeding what is available. Competition for observing time in the months of March and April, when the North Galactic Pole is high in the sky, is particularly ferocious.

For a typical semester, between 50 and 60 proposals will be submitted. Each proposal comprises a scientific justification of up to five pages of text, up to two pages of illustrations, and at least five pages of additional information. Each committee member reads all of these proposals—a daunting task—and ranks them. About three weeks after the proposal deadline, the committee members meet for an often long (and usually exhausting) meeting, during which each proposal is thoroughly discussed. The meeting typically lasts two to three full days. The committee produces a prioritized list of recommended proposals for each telescope and forwards this to the IfA director. The approved programs are then forwarded to the directors of the respective telescopes for scheduling.

For classically scheduled observing, in which each project is assigned one or more specific nights, astronomers remain at the mercy of the weather. Poor luck with the weather can set back an observing program by a year. However, high-ranked programs on queue-scheduled telescopes, which include the Gemini North Telescope and the Canada-France-Hawaii Telescope, have a high likelihood of being completed, independent of the weather. This is because in queued observing, a list of objects to be observed is submitted for each project, and these objects are observed in order of priority by astronomers who work for that observatory. The data they collect is then sent to the project astronomers. Space observatories such as the Hubble Space Telescope also work in this manner.


The current observing schedule for the UH 2.2-meter (88-inch) telescope shows who is observing and what instruments they are using. It also lists IfA observers and equipment on other Mauna Kea telescopes.