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Instructions for Completion of Phase II/OT Science Programs

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This page provides instructions for completing Phase II Science Programs for all Gemini North and Gemini South instruments. It includes submission details and notes of any procedural changes. Please read this page carefully! Once your Phase II is ready you may find it helpful to read the what to expect once your observations are in the queue page.


The Phase II deadline of  is a hard deadline for all queue, classical, and large programs, including those observing Targets of Opportunity. Failure to submit a defined program by the Phase II deadline may result in the program being canceled. Extensions are granted only in exceptional circumstances and only if requested prior to the deadline. The mask design deadlines are more flexible, but we encourage PIs to submit their mask designs and final MOS observations as early as possible. PIs requiring MOS pre-imaging should prepare these observations at the very start of the semester. In all cases it benefits PIs with early targets to get their Phase II ready early, as some programs will be started before the end of the previous semester, especially persistent Band 1 programs.

Phase II Support

All programs are assigned a Principal Support Scientist and one or more Additional Support Scientists. Your program will be supported by a specialist in the instrumentation used by your program, who may or may not be in your home country's NGO. While the Principal Support Scientist is the first point of contact, please include all support scientists in your communications.

Note that we have seen issues in the past where email forwarded from an institutional address to a personal address has caused delivery issues, especially if forwarded to Yahoo or Gmail addresses. To mitigate this potential issue, if you are forwarding your institutional email please provide your alternate email address to your support scientists.

Distribution of Phase II Blueprint

Instructions on initial program retrieval, including database program key passwords, were sent to PIs on . A new version of the Observing Tool (OT) is available for Semester Phase II preparation. Please see the OT installation instructions and the OT Release Notes for a list of changes. If you are unfamiliar with the OT, there are video tutorials that provide a useful introduction, and instructions for obtaining a key and getting started with your program. In addition, each instrument has an "Observation Preparation" section that provides guidance on observing strategies and how to describe these in the OT. The OT/Phase II checklist is another useful reference.

Approved Phase I observations have been used to construct template observations, including calibration observations, in the initial OT program. We recommend that you start the Phase II process using these supplied templates to fully prepare one observation, and have it reviewed by your Support Scientists before starting on any others. There are also OT libraries of complete observation examples which are available for reference, although the OT cannot automatically check for new versions of these libraries, so we recommend that you fetch them manually at the beginning of every Phase II preparation period.

All changes to programs are stored in your local OT. If you want the changes to be permanent, say for working with a collaborator or submitting the observations for review, the program must be "synced" with the appropriate Observing Database. The Phase II workflow is described here.

Persistent Band 1 programs

All programs in Band 1 (except Classical, Fast-Turnaround, Large and Long, Director’s Discretionary, ToO, and limited-term partner programs) are allowed to execute over the full subsequent semester and encouraged to execute late in the semester before their formal allocation begins. These programs, designated "persistent Band 1", are treated equally with other Band 1s, whichever semester they are executing in. Programs using block scheduled instruments (e.g. Visitors, GSAOI, ZORRO, `Alopeke) are extended on a strictly best-effort basis.

Remote Eavesdropping

If your program is in scientific ranking Band 1 or 2, and is not a GSAOI program, we invite you to participate in remote eavesdropping during the observation of your program at Gemini. Successful PIs will receive a link to a Google spreadsheet on which availability for eavesdropping can be indicated. Availability can be entered and modified during the Phase II process or at any point during the semester. However, note that we can observe your targets as soon as all observing conditions are met, and we therefore encourage to fill the availability spreadsheet early to avoid missing any eavesdropping opportunities.

Change Requests

Target changes and other significant modifications to the original proposed observations require approval via the change request process. Changes to Gemini South laser targets must be made no later than 1 week prior to the start of the laser run, and there will be a ~1 week delay scheduling new Gemini North laser targets after approval and observation definition, as summarized in the Table at the bottom of this page.

The observing conditions constraints approved by the ITAC during the Phase I process are the best that may be used when preparing observations. It is always acceptable to relax the conditions, and more relaxed conditions lead to a higher probability of execution (see the advice for band 3 page for tips on how to maximize your chances of getting data). To change to better observing conditions than approved by the ITAC, or to add airmass or hour angle constraints, requires approval.

Classical and Priority Visitor Observer Programs

Please see the schedules page for the dates of your observing runs and the instructions for visiting observers. Information regarding your visit is required at least 4 weeks prior to the run.

Important Deadlines
Phase II deadline is the mandatory general deadlines for all queue and classical programs. The observations must be set to "For Review" by 6pm at the site where the observations are being submitted.
MOS Mask Cutting Deadlines

Update as of Feb 9, 2022 due to failure of Gemini South mask cutting machine.  

MOS masks are currently being cut at Gemini North for both telescopes.  Please allow extra time for delivery to Gemini South

At Gemini North: MOS masks will be cut once a week.

The mask design and corresponding Phase II updates are submitted via the OT and then checked by the Principal Support Scientist before being forwarded to the observatory. Mask designs are checked internally by Gemini staff for technical feasibility at least once per week before being forwarded to the Gemini North and Gemini South mask cutting queue. The time between mask design approval and mask availability for the telescope queue is normally less than 2 weeks for Gemini North and 5 weeks for Gemini South (due to mask shipping time). We strongly encourage all MOS PIs to submit their mask designs as early as possible (either at the start of the semester if not using GMOS pre-imaging or immediately after the pre-imaging is taken) in order to increase the chance that the MOS observations will be completed. Gemini reserves the right not to cut masks submitted within 6 weeks of the period when the program is active if the queue coordinators determine that the MOS observations cannot be scheduled.

Be sure to use the latest version of the mask design software.

Classical and time-critical program PIs must ensure their mask designs have been submitted and cleared the design checks at least two weeks prior to their run

Note that all MOS observations must be defined by the Phase II deadline. Observations without masks will be reviewed and set to "On Hold" until the masks become available, checked and send to cut, at which time the PI will have a chance to make modifications if necessary.

Gemini North Altair LGS target changes Laser target changes require a change request and PIs should expect about a 1 week delay after new targets are approved and defined in the OT before the observations may be scheduled in the queue.
Gemini South GeMS target changes Change requests for target additions and alterations for laser runs must be submitted no later than 1 week prior to the start of each laser run. Laser run dates are shown on the Gemini South telescope schedule.