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Instrument Availability and Target Accessibility: 2007A

Instrument Availability and Target Accessibility: 2007A


This page provides best estimates, at the time of the Call for Proposals, of instrument availability and corresponding target (RA, dec) restrictions for 2007A.

General

Instrument Changes: As there are more instruments than the number of available ports on each telescope, instrument swaps will be required. Therefore not all instruments will be available for the entire semester.  However, whenever possible  instrument swaps will be scheduled to minimize impact on the queue, that is, instrument swaps will be driven by demand as much as possible and so the final schedule will not be made until after the 2007A programs are known.  Never the less, it may be the case that certain targets or entire programs will not be feasible once the final schedule is determined, at ITAC or thereafter.  This is especially true at Gemini South, where a significant fraction of the schedule is reserved for new instrument commissioning.

No instrument changes are permitted during classical runs.

Under-utilized instruments: Community demand is a critical factor in determining instrument availability.  Gemini maintains as a "minimum goal" that any instrument must be awarded at least 160 hours (approx 16 nights) in order to be mounted on the telescope.  In semesters 2006A and 2006B the following instruments only barely or did not meet the 16-night minimum criterion: MICHELLE, T-ReCS, bHROS.  As each instrument introduces significant overhead to the Observatory, and access to instrument ports is at a premium, Gemini reserves the right to withdraw support for any instrument for which this under-utilization condition persists.

Gemini North

At Gemini North, NIFS and Michelle share the up-looking port.  It is expected that Michelle will be mounted at the start of the semester, NIFS will occupy the middle of the semester and Michelle will be re-mounted near the end.  The exact dates of these swaps will be driven largely by consideration of the targets in the queue.  Therefore, there are no special target restrictions on any Gemini North instruments in 2007A.

However, observations requiring the Laser Guide Star (LGS) system are restricted by the limitation that the LGS must be used at or above 49 degrees elevation.  How this translates into RA and dec restrictions is indicated in the figure below.

In addition, because of the requirement to obtain advance approval of all telescope pointings, it is not possible to use LGS with Rapid Response Target of Opportunity observations. Standard ToO LGS observations may be possible in the future if targets can be defined well in advance but are not being considered for 2007A.

The following figure displays the accessibility of targets as a function of RA (horizontal axis) and Declination (vertical axis) at Gemini North for the 2007A semester.  The dark gray area indicates the restriction on LGS observations.  The larger light gray area indicates sky positions that are above 2.5 airmasses for at least 2 hours on at least 7 days of the semester.  Targets outside this area should not be requested in 2007A.  However, these represent the minimum criteria for scheduling an observation in the queue (or classically), and proposers with targets very close to the extremes are advised to consider carefully other factors such as the amount of time needed on the source, the observing conditions required and the likely weather at the time (early in the semester is more likely to have poor weather on Mauna Kea), and the maximum airmass acceptable for the observation.

GN Target Accessibility

Figure 1: Target accessibility at Gemini North during semester 2007A.

Gemini South

At Gemini South, 30% of the semester is reserved for engineering, including new instrument commissioning (both NICI and Flamingos-2) and the start of multi-conjugate adaptive optics (MCAO) commissioning.  NICI will share the up-looking port with T-ReCS and Flamingos-2 will share a side port with GMOS-S.  The start of MCAO engineering will displace Phoenix, which is currently located on the "AO" port.  At this writing, it is expected that NICI will occupy the up-looking port at the start of the semester, followed by T-ReCS for the remainder of the semester.  GMOS-S is expected to be dis-mounted late in the first half of the semester for Flamingos-2 commissioning and then re-mounted near the end of the semester.  bHROS is not available when GMOS-S is off the telescope.  However, given the uncertainty of new instrument commissioning schedules, no special target restrictions are being placed on T-ReCS, GMOS-S, bHROS or GNIRS in 2007A. 

However, it is reasonably certain that Phoenix will be removed from the telescope after March 2007.  Hence, Phoenix targets are restricted to February-March, as indicated in the figure below.

The following figure displays the accessibility of targets as a function of RA (horizontal axis) and Declination (vertical axis) at Gemini South for the 2007A semester.  The dark gray area indicates the restriction on Phoenix observations.  The larger light gray area indicates sky positions accessible at some time during the semester.  Targets outside this area should not be requested in 2007A.  In both cases, accessibility is defined as positions above airmass 2.5 for at least 2 hours on at least 7 days during the semester (or during February-March in the case of Phoenix).  However, these represent the minimum criteria for scheduling an observation in the queue (or classically), and proposers with targets very close to the extremes are advised to consider carefully other factors such as the amount of time needed on the source, the observing conditions required and the likely weather at the time (late in the semester is more likely to have poor weather on Cerro Pachon), and the maximum airmass acceptable for the observation.

GS Target Accessibility

Figure 2: Target accessibility at Gemini South during semester 2007A.



Last update Sept 1, 2006; Bernadette Rodgers