Commissioning. TripleSpec Design Review December 6-7, 2005 Update: March 12, 2008

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1 1 Commissioning Commissioning schedule overview Readiness to ship criteria Shipping and setup plan Daytime commissioning prior to observation On-sky evaluation of instrument performance Telescope time requirements summary

2 2 Commissioning Schedule Preparation Computer configuration testing ( T - 1 month) All instrument functionality in place with instrument specific flexible GUI's. Integration with TUI in progress. Instrument delivery ( T - 2 weeks) T 7 days in practice (instrument should pull up on Friday) Instrument team arrival ( T 5 days) Wilson (T - 8 days); Nelson/Skrutskie (T 3 days) Daytime testing of instrument on/off telescope ( T - 3 days) At APO discretion Observations (5 consecutive half nights allocated for first run; Two more engr runs scheduled) Two half-nights of evening engineering Day off / reserve half-night for evaluation Three full nights of engineering / commissioning science Dark time break (3 weeks) Four half nights for final commissioning

3 3 Readiness for Commissioning In order to be considered ready for shipping the following criteria must be met: Overall system No detectable warm leaks with helium leak checker. (Evaluate post cooldown pressure to assure no evidence for cold vacuum leaks.) Not quite. We lost access to the robust helium leak checker. The system was checked early on. Pumpdown and vacuum performance are the same as then. Cryogenic hold time > 36 hours. Measured at > 96 hours. All electronics and telemetry operating nominally, fully cabled and mounted in operating configuration. Instrument fully integrated with instrument cart. Both of the above items have been met. Alignment stable for at least three thermal cycles. Four UVa cooldowns with detectors. Spectrograph and slit viewer focus change between #2 and #3. Spectrograph and slit viewer stable between #1-2 and #3-4. Focus change as predicted by models.

4 4 Readiness for Commissioning In order to be considered ready for shipping the following criteria must be met: Slit Viewer channel Read noise <30 electrons in CDS (likely met) Dark current <100 electrons/s (weak requirement due to Ks background expect < 1 e-/sec) (likely met) Image degradation due to de-focus/tilt < 1 pixel (0.25 ) across array referenced to slit (ensquared energy criterion - >80% in a 4x4 pixel box) (TBD at telescope; confidence from reimage fiber end with <2 pixel FWHM) Throughput, including array quantum efficiency, >30% (TBD; thermal background levels as expected) Pupil location consistent with <5% misalignment at secondary mirror (met) Slit image motion due to axial rotation flexure < 100 um at array (met)

5 5 Readiness for Commissioning In order to be considered ready for shipping the following criteria must be met: Spectrograph channel Read noise < 15 electrons for CDS ( <16 e- Fowler 1; <5 e- Fowler16) Dark current < 0.1 electrons/second (measured at 0.15 e-/s at sea level, expect 2x lower on mountain) HAWAII-2 temperature stabilized to +/- 0.1K (maybe? not sure there is a significant requirement here; currently stabilized to auxiliary tank LN2 bath through significant heat strapping) Monochromatic slit image degraded by no more than 0.5 pixel at any position between 0.9 and 2.3 micron need to develop an appropriate ensquared energy spec. (focus analysis shows consistent 2 pixel psf across array; expected aberrations at edges/corners degrade to 3 pixels) Measured throughput exceeds 15% between 1.2 and 2.3 um (working on it... relative response looks identical to Cornell, stars will be the best arbiter.) Scattered light and ghosting from thermal background does not degrade background limited performance (along with no egregious ghosts from bright targets) (no problem)

6 6 Pre-ship Computer Testing This was just not feasible given the manpower commitment to the hardware. Prior to the shipment of the instrument to APO we will install and test the computer interfaces on site. This exercise will occur at least one month prior to instrument delivery at APO. Simulators will produce a data stream comparable to the output of both the slit-viewer and science-array channels. The exact timing of this exercise will be chosen to have minimum impact on the laboratory testing and commissioning of the main instrument (but may lead to a week of downtime for lab end-to-end testing).

7 7 Shipping Given authorization, the instrument and cart will be driven to APO by UVa staff no less than two weeks prior to its first night of operation. The instrument will be cooled immediately upon arrival and checked for functionality and stable alignment. The instrument will be left ready for observation. The full commissioning team will arrive 5 days before the first scheduled observations for final configuration and off-telescope / daytime testing.

8 8 Daytime Testing Both at the initial observatory cooldown and immediately before the observing run: Evaluate functionality and noise performance of the two imaging systems. Check alignments with telescope analog and monochromator Test system off (and possibly on) telescope Room lights and daylight sky with the mirror covers closed will provide useful calibration and test data. The pupil location relative to the secondary will be mapped (although this should not be necessary give lab alignment) Collect dome flats, dark frames, calibration lamp frames,...

9 9 Daytime Testing Astronomical observations to test the slit viewer channel can be conducted in daylight or bright twilight. Preliminary instrument blocks can be constructed in early twilight (as was done for CorMASS). Overall, the daytime/lab observations should largely validate the system for science readiness and efficient use of the allocated engineering commissioning night time.

10 10 On-sky Testing Chronology Validation of secondary illumination (1.5 hours) Target: any 6 th magnitude star The re-imager Lyot stop is shared by the slit-viewer and the spectrograph. Out-of-focus images on the slit-viewer will validate the alignment of the Lyot stop on the center of the secondary. A weak double-check can be made by looking at spectra of de-focused sources. Turning the rotator will confirm axial alignment of the emerging beam. Tolerance: Lyot boresight <5% off from center of secondary Illumination variation with rotation will not compromise photometry at >2% level

11 11 On-sky Testing Chronology Bright star spectrum (10 minutes) A first-light indulgence, while a bright star is handy. Ideally an A0 star for spectral throughput (Cornell is standing by to evaluate) Instrument block definition (1.5 hours) The slit viewer will provide real-time (frame-persecond) feedback for constructing an instrument block (a procedure which worked efficiently with the CorMASS slit viewer). With a 4 arcminute field initial source acquisition should be straightforward (it wasn t too difficult even with the 13 arcsec field of CorMASS) UVa must provide a utility for rapid (x,y) centroiding on the HAWAII-1 array

12 12 On-sky Testing Chronology Slit viewer characterization (1 hour) Star cluster Check slit image position vs. rotator position (daytime) Validate image quality and measure distortion across field (star field or cluster). Evaluate sensitivity using 2MASS photometry collect data to document limiting magnitude for guiding vs. integration time (can be done in parallel with spectroscopic observations throughout the night). Measure Ks-band system emissivity Evaluate interaction between bright stars and slit (slit edge effects, scattered light...)

13 13 On-sky Testing Chronology Basic spectrograph characterization (4 hours) Target spectral type A0 and G2 standards (magnitude 7-9) for primary quantitative continuum tests and bright planetary nebulae (NGC 7027) for emission line characterization. Collect data to evaluate the fundamentals HAWAII-2 focus and tilt slit response function along and across slit system throughput as a function of wavelength on-sky wavelength calibration

14 14 On-sky Testing Chronology Basic spectrograph characterization (continued) Target magnitude white dwarfs to evaluate ultimate system sensitivity for long integrations. establish background limited integration times in spectral regions between airglow lines as a function of wavelength. Observe at least one science rich target (e.g. NGC1068) which highlights both spectroscopic resolution and long slit capability.

15 15 Observing time requirements The on-sky tests in the previous slide will occupy the better part of two half nights. ideally these will be the first half so that the team can focus on data analysis in a well-rested state the subsequent morning/afternoon. A third contingency half night should be available with the expectation that it will be allocated to an ARC science program on another instrument if sufficient data have been collected to that point. TripleSpec staff will use the break for data analysis.

16 16 Observing time requirements A three full-night science run will follow presuming the instrument is in acceptable condition. As with the first CorMASS commissioning run we will observe a mix of targets those of interest to the instrument team as well as those requested by the ARC community. Raw data will be accessible to all (as well as the adapted SpexTool algorithms).

17 17 Observing time requirements We will address remaining software/hardware configuration issues during the dark-time period and return for four half-nights of final engineering/science toward the end of the next bright time period. The instrument will be ready for general use following this second observing run.