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Semester 2016A Instrument Availability and Target Accessibility

This page provides best estimates, at the time of the Call for Proposals, of instrument availability and target (RA, dec) restrictions for 2016A.

 

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Instrument and Instrument Configuration Restrictions

At each Gemini telescope, instruments are mounted at the Cassegrain focus on the instrument support structure (ISS). A science fold mirror mounted inside the ISS can be rotated to send the light from the telescope to any of four side-looking ports, or can be retracted so that the light goes to the up-looking port. At each site, the calibration unit and the Adaptive Optics system use two of the side ports, leaving two side-looking and one uplooking port for other instrumentation. As more than three instruments are offered each semester, instrument swaps will be required and not all instruments will be available for the entire semester. Instrument swaps will be driven by demand and scheduled to minimize impact on the queue. Certain targets or entire programs may not be feasible once the final schedule is determined, at ITAC or thereafter. If an instrument is requested for less than 6% of the Bands 1+2 time, the Observatory reserves the right to limit the RA range available to programs, or to not schedule the instrument. Changes to the instrument mounting are not permitted during classical runs.


 


 

 

Non-Sidereal Targets

Non-sidereal targets can have a broader range in RA than indicated in the Tables below due to, for example, the need to observe comets relatively close to the Sun. The ephemeris for any submitted target however must include a position that is accessible between evening and morning twilight at some point in the semester. For rapidly moving targets PIs should specify in the proposal when the target is accessible, and the coordinates of the target at that time, so that the observation can be checked for feasibility.


 


 

 

Time-Critical Observations

Gemini Observatory attempts to schedule all time-critical observations whenever possible within the constraints imposed by instrument availability, instrument configuration, weather, and science ranking band. Additional, nights not scheduled for multi-instrument queue including classical and other observing modes, fast-turnaround blocks, shutdowns, commissioning, etc., impose additional constraints on time-critical programs. Short observations (~1 hour) can often be accommodated during fast-turnaround and priority observing periods. Programs with time-critical observations are encouraged to include detailed scheduling constraints with their proposal, such that they can be considered along with other constraints when developing the telescope schedule each semester.


 


 

 

Gemini North Instrument Availability and Target Accessibility

All instruments are restricted for sky visibility as described in the Table and Figure below. In addition:

  • TEXES will be available for up to 100 hours, subject to demand, in June; targets are therefore limited to RA 12h to 0h.
  • The Laser Guide Star (LGS) system must be used at or above 40 degrees elevation. How this translates into RA and dec restrictions is indicated in the Table.

 

 


Accessible Restricted** Inaccessible
Declination,
non-LGS
-30° to +73° -37° to -30°,
+73° to +90°
< -37°
Declination,
LGS
-22° to +65° -27° to -22°,
+65° to +68°
< -27° and > +68°
Right Ascension,
non-LGS
7h to 22h 4h to 7h,
22h to 1h
1h to 4h
Right Ascension,
LGS
8h to 21h 5h to 8h,
21h to 0h
0h to 5h
Right Ascension,
TEXES
14h to 22h 12h to 13h,
22h to 0h
0h to 12h

**Due to limited sky availability during the semester, GMOS MOS programs requiring pre-imaging should not have targets in this region, and other programs with targets in this region should not require a large amount of time, or have strict timing or observing constraints.


 


 

 

Gemini South Instrument Availability and Target Accessibility

All instruments are restricted for sky visibility as described in the Table and Figure below. In addition:

  • Observations using GeMS are restricted to greater than 45 degrees elevation. How this translates into RA and dec restrictions is indicated in the Table.
  • GSAOI observations will likely be limited to three scheduled blocks in 2016A. The scheduling of these blocks will be informed by demand.
  • DSSI will be available for up to 100 hours, subject to demand, in the second half of the semester; targets are therefore limited to RA 12h to 1h.
  • Phoenix will be available for up to 150 hours, subject to demand, in the second half of the semester; targets are therefore limited to RA 12h to 1h.
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Accessible Restricted** Inaccessible
Declination -87° to +22° -90° to -87°,
+22° to +28°
> +28°
Declination,
GSAOI + GeMS
-70° to +10° -75° to -70°,
+10° to +15°
< -75° and > +15°
Declination,
GPI
-75° to +15° -80° to --75°,
+15° to +20°
< -80° and > +20°
Right Ascension 7h to 23h 5h to 7h,
23h to 2h
2h to 5h
Right Ascension,
GSAOI + GeMS
8h to 21h 6h to 8h,
21h to 22h
21h to 6h
Right Ascension,
DSSI, Phoenix
13h to 23h 12h to 13h,
23h to 1h
1h to 12h

**Due to limited sky availability during the semester, GMOS MOS programs requiring pre-imaging should not have targets in this region, and other programs with targets in this region should not require a large amount of time, or have strict timing or observing constraints.


 


 

 

Graphical Illustration

 

GN Target Accessibility

Figure 1: Schematic representation of target accessibility at Gemini North during semester 2016A. Green regions offer unrestricted access, red regions are inaccessible. Hatched areas indicate the more restricted LGS regions. The yellow region is possible, but restricted. See text, and values in the Gemini North Table above.

 

GS Target Accessibility

Figure 2: Schematic representation of target accessibility at Gemini South during semester 2016A. Green regions offer unrestricted access, red regions are inaccessible. Hatched areas indicate the more restricted GeMS regions. The yellow region is possible, but restricted. See text, and values in the Gemini South Table above.