NIRI Most Common Errors for Phase II

• Guider:
  • Guidestars: (1) are too faint, (2) are inaccessible by the probe arm in some or all offset positions, (3) cause the probe arm to occult the detector or slit in some or all offset positions. Use the Position Editor (the "Image" button in the main OT menu) in the OT to visualize the offsets and probe positions for your field.
  • A Guide star is defined but is parked/frozen when pointing on source or is active when pointing off source. Fix this in the offset iterator by setting the PWFS to the appropriate guide star or "park" or "freeze".
• OT Setup:
  • No (or not enough) acquisition observations are defined (including slit images). Use the NIRI OT library routines for acquisition examples.
  • Observations are (1) not prioritized, (2) not RA ordered or (3) not grouped for clarity. This can cause confusion at the telescope. Priority should be set for every observation. Observations can be reordered by dragging them to the top level of the OT program. Groups can be reordered by dragging a single observation in the group to the top level of the OT program, which will move all observations and the group.
  • Observing conditions are too strict. Choose the most relaxed conditions that can be tolerated and still meet the science goals. The sky background, which refers to optical sky background, should be set to "Any" for almost all near-IR (1-5 microns) observations. The water vapor should be set to "Any" for 1-3 micron observations, and carefully considered for observations at wavelengths >3 microns (see here for more information).
  • Observing conditions for acquisition & target observations don't match. Please set the constraints to be identical for the acquisition and science. This will keep your observations together when the OT is searched based on conditions.
  • No observe component is defined (and therefore no observations will be taken).
  • Observations are longer than 3 hours of spectroscopy or 4 hours of imaging. See smallest schedulable elements.
  • There are no notes to the observer. Notes are particularly important in the following cases: (1) the observing conditions are unusual or cannot be fully specified in the "Observing Conditions" component, (2) there are special temporal constraints for the observations, (3) science targets are expected to be close to saturation, (4) there are very bright non-science targets in the field which can be saturated and (5) the science target is not obvious. See Note.
  • No finding chart has been submitted for fields where confusion is an issue or the OT Image Server are not good enough. Send finding charts to your contact scientist.
  • Filter change / dither position iterators are in the wrong order leading to large overhead times.
• Detector:
  • Exposure times are inappropriate. Too short if they violate (1) Minimum possible exposure time, (2) Minimum recommended exposure time, or (3) simply add excessive readnoise when saturation is not an issue. Too long if they allow (1) saturation of the sky (particularly in L and M), (2) saturation of the source or (3) sky lines to change too much between dither positions.
  • NIRI Detector Modes (Readmode, Well Depth or Subarray size) are inappropriate for the science goals or integration times.
  • The Subarray size changes between the science target, calibrations and standards.
  • The "Spectroscopy 1024x512" subarray size should not be used, because it does not decrease array readout time.
• Standards and Calibrations:
  • No flats or arcs (for spectroscopy) are defined. These calibrations should be explicitly defined in the science program, although time will not be charged to the PI for these observations.
  • Telluric standards (spectroscopic modes) or imaging standards (found in the NIRI OT Library) are not defined.

Last update 2006 September 1; Andrew Stephens, Tom Geballe & Joe Jensen