- There is no charge to the program for baseline calibrations: 1 telluric per science observation, and flats and arcs. TO REMOVE THESE CALIBRATIONS FROM THE TOTAL PLANNED TIME, BE SURE THAT THE "OBSERVE CLASS" (set in "Observe") is set to "NIGHTTIME PARTNER CALIBRATION" ("CALIBRATION ACQUISITION" for telluric acquisition observations). - Additional calibrations are charged to the program and should have Observe Class = "Nighttime Program Calibration" - Acquisition observations should have Observe Class = "Acquisition" (for science) or "Calibration Acquisition" for tellurics. - The OT does not account for readout time or file writing, and assumes a fixed overhead of 10secs per telescope offset or instrument config. change. In many cases the readout overheads are negligible, however for many short observations/coadds (as in thermal IR) or large offsets to sky, the overheads could be significant. Consult the web pages. Top Fifteen or so Questions to ask yourself before submitting your Phase II: 15. Is your GUIDE STAR a real point source, in the correct annulus and brightness range? (See webpages for details.) Note that the GNIRS OIWFS is NOT available yet. Have you specified just ONE guide star? 14. Have you selected the right PIXEL SCALE and DISPERSER combination? (For 0.15" pixel scale, 32l/mm gives R~1700, 110l/mm gives R~5900 in 2 pixels.) 13. Do you have CROSS-DISPERSED selected, if desired? Note that the XD tab provides information on the wavelength coverage in each order, it is not an input field. 12. Do you have the correct SLIT WIDTH set? Have you considered the tradeoff of slit-loss vs. resolution in selecting the slit width? 11. Is the Position Angle (PA) set, if non-zero? 10. If you are using the 111 l/mm grating, do you have the right CENTRAL WAVELENGTH set? For the 32l/mm (with 0.15pixel scale), did you set the appropriate wavelength via the pull-down menu options? (except L band, which requires 2 settings for full coverage). 9. Is the EXPOSURE TIME set properly? Are COADDS set if needed? 8. If you are using the GNIRS ITERATOR, did you adjust the exposure time/coadds appropriately for each wavelength setting? 7. Is the READMODE set correctly for the type of observation and exposure time that you are using? (In general, use the lowest readnoise mode that fits easily within your exposure time, but beware that low noise reads add overhead-- a 30sec exposure does not need LNRs=32 which would add 18secs for readout). 6. Is your OFFSET SEQUENCE set up properly? Note that dithers ALONG the slit are offsets in Q. Use the position editor (zoomed in) to check your offset positions. Is your offset iterator INSIDE your GNIRS iterator, if you have one? 5. Are your OBSERVING CONDITIONS set properly? (Did you use the SAME observing conditions when calculating exposure times in the ITC?) 4. Have you included TELLURIC STANDARDS appropriate for your observation? For observations greater than ~20 minutes, have you included before and after tellurics? Are all GCAL calibrations included, either within an observation sequence or as a separate observation? 3. Are there concise and detailed NOTES for acquisition instructions, desired S/N, or other relevant comments to pass to the observer? Have you sent a FINDING CHART if needed? For BLIND Acquisitions (H>~18), have you consulted the instructions on the web? 2. Do you have OBSERVEs inserted at the inner most level of your observing sequence? (If not, everything you've done has just been an idle exercise!) TIP: use the sequence tab to check the final sequence that is assembled. 1. Do you have ACQUISITION observations defined for all science targets and standards? 0. Is the "Observe Class" set properly for all observes? The "GNIRS Sequence" iterator allows the PI to iterate over most of the GNIRS mechanisms. This is provided primarily for defining acquisition observations, however, FOR MOST OBSERVATIONS, MANY OF THESE ELEMENTS DO NOT NEED TO BE SET. A standard acquisition sequence (see examples) includes the following items: -Acq. mirror (IN) -Filter (usually H, or H2 for tellurics and bright objects) -Readmode (usually Bright or Acquisition) -Decker -Slit width -Exposure time -Coadds A science sequence can include ONLY the following items: -central wavelength -exposure time -coadds -cross-dispersed -disperser -slitwidth A change in central wavelength DOES NOT require the filter to be specified (the instrument sequencer takes care of it) It is NOT possible to sequence non-thermal (<2.5um) and thermal (>2.5um) exposures together (due to different detector bias). ACQUISITION and SCIENCE EXPOSURES ARE DEFINED IN SEPERATE OBSERVATIONS. Acquisition observations should have Observe Class = "Acquisition", or "Calibration Acquisition" for baseline calibrations. The PI must define ALL observations for their program, including: --Acquisition observations for all targets and configurations --Telluric standards accessible before and after all science targets, and for all configurations --Flats and Arcs for all configurations Example acquisition and telluric observations are included here. See "GS-GNIRScal-library" program for example flats and arcs. None of the examples here include flats and arcs; however, flats and arcs can be embedded inside observing sequences, EXCEPT for XD flats which must be run at the end of the night (due to saturation). All baseline calibrations should have Class (set at the Observe level) set to "Nighttime Partner Calibration". Non-baseline calibrations (e.g., additional tellurics or radial velocity standards) should have Class="Nighttime Program Calibration". The PI must provide telluric standards that can be taken before or after their science observation (for short observations it can be the same telluric). Be sure to select a telluric of the appropriate spectral type and with an airmass close to your target BEFORE or AFTER the target is observed. Note that if one telluric will suffice for multiple objects it is NOT necessary to define it multiple times, simply tell us this in a note. HOWEVER, there must be at least one telluric observation defined for EACH instrument configuration. Darks: The GNIRS dark current is very low and flatfield exposure times are generally short, so darks are not normally taken as part of baseline calibrations. In addition, darks are not generally needed for science exposures as the sky-subtraction process removes the dark current. Therefore, PIs MUST REQUEST (and define) any darks they wish to have. These will be done during afternoon calibrations and so incur no charge. Set Class="Daytime Calibration". This OT program library contains some examples of GNIRS observations. Starting with 2005A, all GNIRS programs must include --Acquisition observations for all targets --Baseline calibrations: telluric standards, flatfields and arcs (no charge) --Any additional calibrations (charged to program) Examples of GCAL observations (flatfields and arcs) are in the GS-GNIRScal-library. There are 2 recommended methods to organize your observations: 1) Group tellurics (2 per observation-- before/after) and calibrations with the science observation and corresponding acquisition observations. Rename the group to the name of the science target. This approach is best when there are multiple configurations, and/or few science targets. 2) Define tellurics and calibrations seperately, to be reused for all targets. This approach is better when there are numerous targets using the same calibrations or same set of tellurics. Baseline cals (including tellurics) DO NOT need to be repeated for every science target-- they will be copied to the baseline calibration program for the night, however they must be at least 1 for each instrument configuration. IT MUST BE CLEAR WHICH CALIBRATIONS (tellurics and flats/arcs) GO WITH WHICH OBSERVATIONS. Baseline telluric observations should be given Class="Nighttime Partner Calibration" (at the "Observe" level); additional tellurics or other non-baseline nighttime observations should be given Class="Nighttime Program Calibration" (ie, charged to program). All science observations (but not the acquisitions) have Class="Science". Flat and arc "observes" can be defined in a seperate observation, or inside a sequence. IF the observation is iterating over grating position (wavelength or resolution), the arcs (and flats if repeatability is critical) must be sequenced inside the science observation. Overheads associated with readout are not included in the OT (yet). The readout time is ~0.2sec. This is negligible for most observing times, EXCEPT thermal. In the M-band, the max. exposure time with the 110 line grating (to avoid saturation) is 0.5sec. Therefore one should expect roughly 50% overhead per exposure. L-band is significantly better. One can go 15-30 seconds with the 110 grating, depending on the wavelength setting. In addition, for best sky subtraction, one generally keeps the time between dithers quite short for thermal observations (generally <1 minute, sometimes much less). This also adds overhead. To minimize this, keep the offset distances short, 5 arcseconds or less if possible (assuming point source target). The telescope system is able to recover the guiding much more quickly with small offsets. (Remember that when repeating an offset sequence, the last offset in the sequence is followed by the first!) 1 order 4 (H) Bright Objects acquisition GNIRS 5.0 2 0.30 arcsec acquisition in in Overheads associated with readout are not included in the OT (yet). The readout time is ~0.2sec. This is negligible for most observing times, EXCEPT thermal. In the M-band, the max. exposure time with the 110 line grating (to avoid saturation) is 0.5sec. Therefore one should expect roughly 50% overhead per exposure. L-band is significantly better. One can go 15-30 seconds with the 110 grating, depending on the wavelength setting. In addition, for best sky subtraction, one generally keeps the time between dithers quite short for thermal observations (generally <1 minute, sometimes much less). This also adds overhead. To minimize this, keep the offset distances short, 5 arcseconds or less if possible (assuming point source target). The telescope system is able to recover the guiding much more quickly with small offsets. (Remember that when repeating an offset sequence, the last offset in the sequence is followed by the first!) This telluric is good before or after observations # 1,2 and 3; and after obs #5. Please adjust the exposure time if necessary. Desired S/N in standard is 200. (for example). order 4 (H) H2: 2.12um 1 Acquisition acquisition GNIRS 3 0.2 0.30 arcsec acquisition in in This telluric is good before or after observations # 1,2 and 3; and after obs #5. Please adjust the exposure time if necessary. Desired S/N in standard is 200. (for example). Targets fainter than H~18 require "blind" acquisition, i.e. offset from a nearby reference star. Please consult the web pages for instructions. 1 3 order 4 (H) order 4 (H) Bright Objects acquisition GNIRS 3.0 10 0.45 arcsec acquisition in in There is a drift between GNIRS and the PWFS that causes the object to move out of the slit over time. Recommended maximum elapsed times between recentering is not more than 90 minutes. See web pages for more information. Acquisition: The PA is chosen to align with the major axis of the galaxy. In the IR the brightest spot defines the center, so this is where you should peak up. order 4 (H) H2: 2.12um 1 acquisition Bright Objects GNIRS 5.0 10 0.45 arcsec acquisition in in Acquisition: The PA is chosen to align with the major axis of the galaxy. In the IR the brightest spot defines the center, so this is where you should peak up. S/N: Minimum S/N is 30 per resolution element. 2 1 GNIRS 120.0 60 2.2 1.63 order 4 (H) H2: 2.12um 1 Acquisition acquisition GNIRS 3.0 0.2 0.30 arcsec acquisition in in order 4 (H) order 4 (H) 1 4 Acquisition Bright Objects acquisition GNIRS 5.0 10.0 1.0 arcsec acquisition in in order 4 (H) H2: 2.12um 1 1 acquisition Acquisition Acquisition GNIRS 5.0 0.2 1.0 arcsec acquisition in in order 4 (H) 1 Acquisition acquisition IFU 4 10 acquisition IFU in