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2005B Instrument Availability and Target Accessibility

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Instrument Availability and Target Accessibility: 2005B

The tables below indicate the current best estimates of instrument availability and corresponding target (RA, dec) accessibility for 2005B. Typically several observations or programs are rejected at the ITAC each semester because of target accessibility so please read carefully the following notes:

  • For each given declination, the table shows the target RA that has two hours above airmass = 2 at the start of the night early in the semester ("minimum" RA) and the target RA that has two hours above airmass = 2 at the end of the night late in the semester ("maximum" RA).
    • For some high and low declinations (noted *), an airmass limit of 2.5 is used.
    • If best image quality is desired, typically achieved at smaller zenith distance, the RA range should be reduced appropriately.
  • The comments column indicates whether all RAs are potentially observable. 
    • "no restriction" means that all RAs are potentially observable. 
    • "restricted" means that only RAs between the "minimum" and "maximum" can be accepted for observation in this semester. Targets with RA less than the "minimum" will set too early in the night and cannot be observed; targets with RA greater than the "maximum" will rise too late in the night and cannot be observed.
  • At the extrema of the RA range, shown by the early- and late-semester values, targets may not be observable in practice due to detailed instrument and engineering schedules and other constraining factors (e.g. lunar phase). Moreover, the time for which the target (RA, dec) is accessible may be very limited and applicants should bear this in mind for faint targets. The likelihood of execution is greatly increased if extreme RAs are avoided.
  • In some cases, an instrument or instrument mode is foreseen to be available for only part of the semester. Such instances are listed after the main table. 

Gemini North

Instrument(s) declination
RA range (hh mm)
Comments "minimum" RA
(early semester)
"maximum" RA
(late semester)
NIRI (including Altair)

GMOS North


80 *  no restriction 14h 50m 15h 50m
70  no restriction 15h 20m 15h 20m
60  no restriction 14h 40m 15h 50m
50  no restriction 14h 40m 16h 00m
40   no restriction 14h 30m 16h 10m
30  no restriction 14h 40m 16h 00m
20  no restriction 14h 50m 16h 00m
10  no restriction 15h 00m 15h 40m
0  no restriction 15h 10m 15h 30m
-10  restricted 15h 30m 15h 10m
-20  restricted 16h 00m 14h 40m
-30  restricted 16h 40m 14h 00m
-40 *  restricted 17h 00m 13h 40m
HIRES (on Keck) all  restricted Available for one night around 12-16 August, two nights around 20-24 October and two nights around 7-11 December

(Precise dates TBD)


Gemini South

Instrument(s) declination
RA range (hh mm)
Comments "minimum" RA
(early semester)
"maximum" RA
(late semester)
GMOS South



Acquisition Camera

30 *  restricted 16h 00m 12h 00m
20  restricted 15h 40m 12h 30m
10  restricted 14h 50m 13h 10m
0  restricted 14h 20m 13h 50m
-10   no restriction 13h 50m 14h 10m
-20  no restriction 13h 40m 14h 30m
-30  no restriction 13h 20m 14h 50m
-40  no restriction 13h 00m 15h 00m
-50  no restriction 12h 50m 15h 20m
-60  no restriction 12h 40m 15h 30m
-70  no restriction 12h 30m 15h 40m
-80  no restriction 12h 20m 15h 50m


(may be unavailable in August due to installation of new lenses)

30 *  restricted 18h 00m 12h 00m
20  restricted 17h 40m 12h 30m
10  restricted 16h 50m 13h 10m
0  restricted 16h 20m 13h 50m
-10   restriction 15h 50m 14h 10m
-20  restriction 15h 40m 14h 30m
-30  restriction 15h 20m 14h 50m
-40  no restriction 15h 00m 15h 00m
-50  no restriction 14h 50m 15h 20m
-60  no restriction 14h 40m 15h 30m
-70  no restriction 14h 30m 15h 40m
-80  no restriction 14h 20m 15h 50m

Last update February 26, 2005; Phil Puxley

Gemini Observatory Participants