About Gemini Observatory


The Gemini Observatory consists of twin 8.1-meter diameter optical/infrared telescopes located on two of the best observing sites on the planet. From their locations on summits in Hawai‘i and Chile, Gemini Observatory’s telescopes can collectively access the entire sky.

Gemini was built and is operated by a partnership of 7 countries including the United States, United Kingdom, Canada, Chile, Australia, Brazil, and Argentina. Any astronomer in a partner country can apply for time on Gemini, which is allocated in proportion to the amount of financial stake of each country. For more information on the Gemini telescopes and technologies visit this site.

Observing with Gemini

Observing with Gemini is a six step process:

Step 1: Develop a fantastic science idea! Check the Gemini instrumentation suite to see which Gemini instrument best fits your scientific goals. Gemini offers a variety of optical, NIR, and MIR instrumentation.

Step 2: Write a proposal. Multi-partner collaborations must use the Gemini proposal submission software, the Phase I Tool (PIT) but everyone is encouraged to take advantage of this tool. Proposals should be submitted to your local NGO office. Details of the submission and review process vary from partner to partner.  Links to NGO office deadlines, and requirements can be found here.


Step 3: Once a proposal has been accepted, PIs can provide and refine information about their targets, observing conditions, guide stars, instruments set-ups, etc. using the Observing Tool (OT) software provided by Gemini. This PHASE II process insures that Gemini has all the information that a Ph.D. service observer or classical observer would need to complete the observations at the telescope. The Phase II process must be completed by a particular deadline for each semester and is required for queue and classical programs. Programs will be reviewed by staff at both the partner NGO office and either Gemini North or Gemini South.


Step 4: Once a National Gemini Office contact and a Gemini Contact Scientist approves your “Phase II” your program is ready for observation. If the program was designated for queue mode, Gemini will observe science targets when the requested conditions match the nightly conditions, with preference given to programs in higher bands. Classical programs will be set to “ready” until the visiting PI’s assigned night.

Step 5: All science (and calibrations/metadata) obtained at Gemini are archived and available within minutes to PIs through the Gemini Science Archive (GSA). The password-protected data are proprietary for 18 months before public access is allowed through the GSA. The GSA is managed and maintained by the Canadian Astronomical Data Centre.

Step 6: Use the Gemini provided data reduction software and related packages to help reduce your data. Analyze your data and publish your results!

Gemini was designed from the beginning with QUEUE SCHEDULING as its primary operational mode. A suite of instruments is simultaneously mounted to the back of the telescope and  instrument switches can be executed with a minimum of overhead.  This allows observation of a wide variety of optical and infrared programs on any given night. Observations defined by the investigators are carried out on their behalf in the requested atmospheric conditions by Ph.D. astronomers  who are specially trained to use all instruments.

The Gemini queue process aims to match weather conditions to the observational constraints of each program, complete the greatest number of scheduled programs each semester, and ensure the best possible data for investigators.

Gemini also offers CLASSICAL OBSERVING. In this mode, PIs or Co-Is travel to the observatory to complete their own observations on assigned nights.

Science Visitors at Gemini

Applications for time on Gemini are made through National Gemini Offices (NGO). Each partner country runs their own National Time Allocation Committees (NTACs) who rank top rated proposals and pass these forward to the International Telescope Committee (ITAC). The ITAC then merges the proposals to create a single combined list of programs for execution. Proposals are solicited by Gemini every 6 months in early March and September.

Gemini Observatory welcomes a variety of science visitors, including classical observers, students, and members of the National Gemini Offices. But did you know that PIs with programs in the current semester’s queue are also invited to visit the observatory?

During their visits, queue PIs can work with Contact Scientists in our base facilities in La Serena or Hilo, accompany queue observers on observing runs, and interact with the local science communities.

Some visiting PIs are thesis students, working on projects involving Gemini data. Others are leading programs with non-standard queue set-ups. However, the observatory encourages any interested queue PI to travel to Chile or Hawaii and learn more about the inner workings of Gemini.

Visits by queue PIs can have positive impacts on the visitors themselves, the institutions they return to, and the science culture at the observatory itself.

Queue PIs interested in visiting Gemini Observatory should contact their National Gemini Offices. Information on lodging, the surrounding communities, and schedules is linked from this page.

For more information visit our webpages at www.gemini.edu