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AUSTRALIAN
NATIONAL UNIVERSITY System Design Note 4.08 Created: 8 February 2002 Last modified: 8 May 2002 |
NIFS VERIFICATION AND COMMISSIONING PLAN
Peter J. McGregor
Research School of Astronomy
and Astrophysics
Institute of Advanced
Studies
Australian National
University
Revision History
|
Revision No. |
Author & Date |
Approval & Date |
Description |
|
Revision 1 |
Peter J. McGregor 29 December 2000 |
Jan van Harmelen 06 February 2001 |
Original document. |
|
Revision 2 |
Peter J. McGregor 08 February 2002 |
Jan van Harmelen 10 February 2002 |
Revised after CDR. |
|
Revision 3 |
Peter G Conroy 02 March 2002 |
Peter J. McGregor 07 May 2002 |
Revised Sections 4.15 & 4.27. |
Contents
4 Verification and
Commissioning Tasks
4.4 Instrument
Rotator Fiducial
4.13 Instrumental
Sensitivities
4.14 Bright Limiting
Magnitude With ND Filter
4.15 Highest
Obtainable S/N Ratio
4.17 OIWFS
Offsetting Accuracy
4.24 Radial Velocity
Stability
4.30
Spectropolarimetry Data Acquisition
4.31
Spectropolarimetry Sensitivity
1 Purpose
This document describes the observations and measurements that will be made during the characterization phase of the Gemini Near-infrared Integral Field Spectrograph (NIFS). The operation of the instrument will be verified and its performance characterized on the Gemini North telescope. This document lists all verification and characterization activities, defines the goals to be met, attempts to schedule these activities, and identifies all personnel and infrastructure resources that will be needed at Gemini North.
2 Applicable Documents
|
Document
ID |
Source |
Title |
|
SPE-I_G0074 |
IGPO |
Programmatic Requirements For Gemini Instrumentation Development |
|
RSAA |
NIFS Operational Concept Definition Document |
|
|
RSAA |
NIFS Integration and Test Plan |
|
|
|
|
|
3 Introduction
The Gemini Near-infrared Integral Field Spectrograph (NIFS) will be used with the ALTAIR adaptive optics (AO) system on the Gemini North telescope. The commissioning phase will be led by Gemini and will extend from first light until the System Verification phase begins. The primary purpose of instrument commissioning is to characterize and calibrate all aspects of the instrument, its use, and its integration with the Gemini control system. This should demonstrate that the instrument is capable of carrying out all the scientific functions for which it was intended. The information obtained will 1) aid potential observers, 2) provide a baseline for future routine calibrations, 3) provide information for the NIFS Users Manual, and 4) be used in finalizing observation preparation tools. Some science data will be obtained during instrument commissioning, but this is not the primary goal. Each scientific mode of the instrument will be tested using science programs outlined in the NIFS OCDD (SDN0003.01).
All commissioning tasks are listed in this plan. An estimate is given of the time required to perform and analyze each observation. These estimates assume that the NIFS Observing Tool is available to automate much of the data taking and that no hardware or software problems are encountered. The total time required for the NIFS Verification and Commissioning is 17 nights.
The NIFS Integration and Test Plan (SDN0004.16) covers post-shipment integration and testing leading up to first light.
4 Verification and Commissioning Tasks
4.1 Initial Field Acquisition
Goal: Acquire the first NIFS target.
Procedure: Slew the telescope to a target field. Deploy the ISS science fold mirror. PWFS1 acquires its guide star. Offset the telescope 20²S. Scan the OIWFS to locate the science object. Offset the telescope 20²N to center the target in the NIFS FOV. Adjust the bore sight using the View Mode Quick Look Display. Offset the OIWFS to locate the OIWFS guide star. Select the OIWFS as the primary tracking reference. Focus the telescope. Deploy the AO fold mirror. The AOWFS acquires its guide star. Reacquire the target in the NIFS FOV. Optimize the ALTAIR servo loop parameters. Record the first-light exposure.
Duration: 6 hours.
Personnel: McGregor, Gemini Instrument Scientist.
Comments: 1. Acceptance test for REQ-OCD-0001.
Success Criteria: First-light image is recorded with near diffraction-limited resolution.
4.2 Cold Stop Alignment
Goal: Check the alignment of the spectrograph cold stop.
Procedure: Center a star in the NIFS FOV and record an exposure. Rotate the ISS science fold mirror to the maximum clockwise position (~ 0.3 of the secondary mirror diameter), offset the telescope to re-center the star, and record an exposure. Repeat in increments of 0.05 of the secondary mirror diameter back to the nominal center position. Repeat in the counter-clockwise rotation direction. Repeat in the orthogonal direction using the ISS science fold mirror tilt. Measure the signal strengths in the seven exposures offset in each direction. Fit straight lines to each set of seven points to infer the ISS science fold mirror orientation where the image of the telescope exit pupil coincides with the NIFS cold stop. Repeat at different attitudes of the telescope.
Duration: 4 hours.
Personnel: Conroy, McGregor, Gemini Instrument Scientist.
Comments: 1. The area of overlap of two offset circles of the same radius is inversely proportional to the offset. We are attempting to measure the angular offset that gives peak signal by fitting line segments to the linear decline on both sides of this peak. The signal should drop to ~ 62% of the peak value at offsets of ±0.3 of the secondary mirror diameter. These line segments should have slopes of ~ ±1.3 (signal fraction per diameter). The uncertainty in the peak value for each line segment is ~ σ/√N, where σ is the fractional error in the measured signals and N is the number of equally spaced samples contributing to the fit. This corresponds to an offset uncertainty of ~ σ/√N/1.3, which should be < 1% of the secondary mirror diameter. This can be achieved with ~ 7 samples if the individual star signals are measured to ~ 3%
2.
ICD 1.5.3/1.9 quotes a specification of 49 μrad (~ 10") for
the probable misalignment error of the telescope beam with respect to the ISS
surface. [PJM: Is there a similar spec for the ALTAIR beam?]
3. The procedure can be use on either a side-looking or the up-looking ISS port because the science fold mirror is always deployed for NIFS to see the ALTAIR field.
4. Acceptance test for REQ-FPR-0002 and REQ-FPR-0200.
Success Criteria: The image of the telescope exit pupil is coincident with the NIFS cold stop to < 1% for any attitude of the telescope.
4.3 Instrument Focus
Goal: Confirm that the spectrograph, OIWFS, and PWFS1 are parfocal.
Procedure: Acquire a smooth spectrum flux standard star. Close the ALTAIR high-order servo loop, but do not correct focus. [PJM: Can this be done?] Center the target in the NIFS FOV. Vary the telescope focus over the permitted range. Measure the spectrograph, OIWFS, and PWFS1 image FWHM at each focus position. Set the telescope focus to the best focus position. Record an OIWFS image to define fiducial positions for the Shack-Hartmann spots. Derive the focus "gain" factor by recording the separation of the OIWFS Shack-Hartmann spots at each focus position.
Duration: 1 hour.
Personnel: McGregor, Gemini Instrument Scientist.
Success Criteria: Spectrograph, OIWFS, and PWFS1 are in focus at the same telescope focus position.
4.4 Instrument Rotator Fiducial
Goal: Measure the orientation of the NIFS IFU with respect to the instrument rotator.
Procedure: Acquire a smooth spectrum flux standard star. Close the ALTAIR servo loop. Center the target in the NIFS FOV. Offset the telescope +1" North. Adjust instrument rotator orientation until offsets of ±1" North-South coincide with the NIFS slitlet orientation. Record this instrument rotator fiducial orientation.
Duration: 1 hour.
Personnel: McGregor, Gemini Instrument Scientist.
Success Criteria: Instrument rotator fiducial angle is determined.
4.5 Offset From Rotator Axis
Goal: Determine the NIFS bore sight offset from the rotator axis.
Procedure: Center the target in the NIFS FOV. Rotate the ISS by 120°. Determine the offset (r,q) from the rotator axis. Enter the values into the telescope pointing model.
Duration: 1 hour.
Personnel: McGregor, Gemini Instrument Scientist.
Success Criteria: NIFS bore sight referenced to ISS rotator axis to an accuracy of < 0.1².
4.6 Pointing Accuracy
Goal: Measure the NIFS pointing accuracy over sky.
Procedure: Slew to targets over whole sky. Record the initial position. Center in the NIFS FOV. Record the pointing errors.
Duration: 4 hours.
Personnel: McGregor, Gemini Instrument Scientist.
Comments: 1. If the pointing error is larger than ~ 1", it will be necessary to build a look up table for the TCS to compensate for flexure between NIFS and the ISS/AG so that objects can be acquired efficiently in the small FOV of NIFS.
Success Criteria: RMS pointing error is determined.
4.7 Image Quality
Goal: Measure the image quality over sky.
Procedure: Slew to targets over whole sky. Optimize the ALTAIR performance. Record images with 60 seconds total integration time to average seeing fluctuations.
Duration: 4 hours.
Personnel: McGregor, Gemini Instrument Scientist.
Success Criteria: Image FWHM with ALTAIR is determined over the whole sky.
4.8 Spatial Pixel Scale
Goal: Confirm the spatial pixel scale parallel and perpendicular to the slitlets.
Procedure: Slew to a precision binary star. Record a frame. Repeat several times. Repeat with offsets perpendicular to the slitlets.
Duration: 2 hours.
Personnel: McGregor, Gemini Instrument Scientist.
Comments: Acceptance test for REQ-OCD-0003.
Success Criteria: NIFS slit widths are confirmed to be 0.103²±0.010² and spatial scale is 0.040²±0.005².
4.9 Astrometric Accuracy
Goal: Measure the astrometric accuracy of NIFS images on the sky.
Procedure: Slew to an astrometric field such as a globular cluster or a field containing many Hipparcos stars. Record target and sky frames. Reformat data to a cube using transformations defined from the wavelength calibration and the Ronchi mask calibration. Spectrally compress cube to an image on the sky. Measure relative positions of stars in the image and compare to astrometric positions.
Duration: 4 hours.
Personnel: McGregor, Gemini Instrument Scientist.
Comments: 1. The WCS transforms will be derived from these data.
2. It is expected that the projection of the individual slitlets onto the sky will be rotated slightly due to the different off-axis angles of each IFU element.
Success Criteria: RMS astrometric accuracy in reconstructed image on the sky is determined.
4.10 Instrument Flexure
Goal: Measure the NIFS internal flexure.
Procedure: Slew to a target near the horizon. Center in NIFS FOV. Record star and arc exposures while tracking over several hours. Measure the position of the object in each image.
Duration: 12 hours.
Personnel: McGregor, Gemini Instrument Scientist.
Comments: 1. Acceptance test for REQ-FPR-0201 and REQ-FPR-0202.
Success Criteria: Instrument flexure < 0.1 pixel per 15° change in orientation.
4.11 System Efficiency
Goal: Measure the system efficiency for each grating.
Procedure: Slew to a smooth spectrum flux standard star. Record spectra with each grating with and without using ALTAIR. System efficiency is calculated from the measured signals. Limiting bright magnitudes are calculated from the system efficiency and the known science detector well depth.
Duration: 3 hours.
Personnel: McGregor, Gemini Instrument Scientist.
Comments: 1. Acceptance tests for RED-OCD-0002 and REQ-OCD-0007.
Success Criteria: Total system throughput, excluding ALTAIR, ³ 15%. Total system throughput, including ALTAIR, is determined.
4.12 Background Brightness
Goal: Measure background brightness for each grating.
Procedure: Slew to blank sky. Record bias frames. Record spectra of one hour duration with each grating. Derive sky brightnesses for each grating using the instrumental responsivities measured in §4.11.
Duration: 5 hours.
Personnel: McGregor, Gemini Instrument Scientist.
Comments: Acceptance test for REQ-OCD-0008.
Success Criteria: External background brightness determined. Internal instrumental background shown to be less than either the external background or the detector dark current, whichever is greater.
4.13 Instrumental Sensitivities
Goal: Confirm instrumental sensitivities for each grating.
Procedure: Slew to a faint target of known brightness. Record spectra of one hour duration with each grating. Measure the signal-to-noise ratio per pixel achieved. Compare with instrumental sensitivity predictions.
Duration: 5 hours.
Personnel: McGregor, Gemini Instrument Scientist.
Comments: 1. This is intended to determine whether systematic noise sources, such as remnance, fringing, bias drifts etc. prevent us achieving the statistical signal-to-noise ratio.
2. Acceptance test for REQ-OCD-0021.
Success Criteria: Extended sources with K band surface brightness of 13.5 mag arcsec-2 and emission-line sources in the K band with surface brightness of 1.5´10-22 W cm-2 arcsec-2 detected in 1800 s with signal-to-noise ratio of 10 at 0.1²´0.1² spatial resolution.
4.14 Bright Limiting Magnitude With ND Filter
Goal: Determine bright limiting magnitude for each grating.
Procedure: Insert the neutral density filter in the Focal Plane Mask Wheel. Acquire a bright star. Record spectra of 10 s duration with each grating. Record the spectra of a flux standard star. Flux calibrate the bright star spectrum and derive its continuum magnitude. Scale to the magnitude of a star that will just saturate the detector.
Duration: 1 hour.
Personnel: McGregor, Gemini Instrument Scientist.
Comments: 1. Acceptance test for REQ-OCD-0022.
Success Criteria: Limiting bright K magnitude ≤ 3.
4.15 Highest Obtainable S/N Ratio
Goal: Measure highest obtainable signal-to-noise ratio.
Procedure: Slew to a smooth spectrum flux standard. Record multiple spectra of appropriate duration. Intersperse with spectra of a second smooth spectrum flux standard for atmospheric absorption correction. Compare the measured signal-to-noise ratios with theoretical signal-to-noise ratio improvement.
Duration: 4 hours.
Personnel: McGregor, Gemini Instrument Scientist.
Comments: 1. Divided spectrum should have a signal-to-noise ratio > 100 in order to measure weak spectral features against a strong continuum.
2. This is intended to determine whether systematic noise sources such as airglow variations, atmospheric transmission variations, and residual spectral features in the smooth spectrum star prevent us achieving high statistical signal-to-noise ratios.
Success Criteria: Highest obtainable SNR is determined.
4.16 OIWFS Repeatability
Goal: Measure OIWFS setting repeatability.
Procedure: Slew to a target. Select the OIWFS as the primary tracking reference. Center the star in the NIFS FOV. Record an exposure. Offset the OIWFS so the star moves 10″ along the NIFS slitlets. Offset the OIWFS back to the original position. Record an exposure. Repeat for positive and negative offsets of different lengths. Measure star positions on all images. Calculate the OIWFS repeatability as the standard deviation of the star positions.
Duration: 4 hours.
Personnel: McGregor, Gemini Instrument Scientist.
Comments: 1. Offsets are in the direction of the NIFS slitlets so that the image centroids are calculated using the 0.04″ pixels in that direction. The slitlets are positioned at 60º with respect to the OIWFS gimbal axis. Hence offsets along the NIFS slitlets will require a two-axis tilt of the gimbal mirror.
Success Criteria: OIWFS has a positioning repeatability of < 0.005².
4.17 OIWFS Offsetting Accuracy
Goal: Measure the accuracy of the OIWFS in performing offsets.
Procedure: Slew to a target. Select the OIWFS as the primary tracking reference. Center the star in the NIFS FOV. Record an exposure. Offset the OIWFS so the star moves 1.00″ along the NIFS slitlets. Record an exposure. Offset the OIWFS so the star moves -2.00″ along the NIFS slitlets. Repeat several times in increments of 0.5″ along the NIFS slitlets. Measure the star centroids on all images. Calculate the OIWFS offsetting accuracy by comparing image displacement in pixels to the requested value using the known pixel scale along the NIFS slitlets.
Duration: 4 hours.
Personnel: McGregor, Gemini Instrument Scientist.
Comments: 1. Offsets are in the direction of the NIFS slitlets so that the image centroids are calculated using the 0.04″ pixels in that direction.
2. Measuring centroids to < 0.005″ using the 0.17″ pixels of the OIWFS requires a SNR of ~ 0.170/0.005 = 34 per pixel.
Success Criteria: The OIWFS offsetting accuracy is determined for offsets between 0.5″ and 2.0″. The OIWFS is inferred to perform offsets of 0.05″ with an accuracy of < 0.005″.
4.18 OIWFS Responsivity
Goal: Measure the OIWFS instrumental responsivity for each filter.
Procedure: Slew to a photometric flux standard star. Record OIWFS images through each filter. Instrumental responsivity is calculated from the measured signals. Limiting bright magnitudes are calculated from the instrumental responsivity and the know OIWFS detector well depth.
Duration: 3 hours.
Personnel: McGregor, Gemini Instrument Scientist.
Success Criteria: NIFS OIWFS has equal or better responsivity than the NIRI OIWFS.
4.19 OIWFS Field-Of-View
Goal: Measure the size of the OIWFS useful field-of-view with ALTAIR.
Procedure: Slew to a photometric flux standard star using ALTAIR. Offset the telescope in a grid to place the star near extremities of the ALTAIR field. Record OIWFS images of the star at each grid position. Repeat using a grid sampling near the NIFS pick off mirror and its support structure.
Duration: 3 hours.
Personnel: McGregor, Gemini Instrument Scientist.
Comments: 1. Accurate knowledge of the NIFS field size with ALTAIR is need for guide star selection.
Success Criteria: OIWFS guide star acquisition field is determined.
4.20 OIWFS Flexure
Goal: Measure the flexure of the OIWFS with respect to ALTAIR.
Procedure: Slew to a smooth spectrum flux calibrator near the horizon. Use the AOWFS for tip-tilt correction. Measure the OIWFS guide star position. Record exposures while tracking over several hours. Measure the position of the object in each image.
Duration: 10 hours.
Personnel: McGregor, Gemini Instrument Scientist.
Comments: 1. OIWFS guide stars will normally not be needed if flexure between ALTAIR and the OIWFS is less than the 0.1 pixel per 15° change in orientation specification.
Success Criteria: Flexure between ALTAIR and the NIFS OIWFS is determined.
4.21 OIWFS Limiting Magnitude
Goal: Measure the OIWFS limiting magnitudes for each filter.
Procedure: Slew to a faint OIWFS guide star of known brightness. Measure the RMS variation in the centroid positions for 100 OIWFS frames. Repeat for a range of OIWFS guide stars of different magnitudes. Determine at what OIWFS guide star magnitude the RMS centroiding error exceeds the diffraction FWHM for each OIWFS filter.
Duration: 4 hours.
Personnel: McGregor, Gemini Instrument Scientist.
Comments: 1. Acceptance test for REQ-OCD-0014e.
Success Criteria: The OIWFS is able to centroid on stars with K < 19 mag in 10 s exposures and do tip-tilt/focus correction on stars with K < 15 mag in 0.1 s exposures.
4.22 Ghost Intensity
Goal: Measure ghost image intensity.
Procedure: Slew to a bright star. Record flat field and sky frames before and after recording deep spectra of the bright star to quantify ghost images due to the bright star. Record bias and flat field frames before and after recording deep sky spectra to quantify ghost images due to sky emission lines.
Duration: 4 hours.
Personnel: McGregor, Gemini Instrument Scientist.
Success Criteria: Ghost images at a level below 10-4 at radii > 2² from parent image.
4.23 Scattered Light
Goal: Measure scattered light intensity.
Procedure: Record bias and flat field frames before and after recording a deep H band sky spectrum. Scattered light intensity is determined from broad wings on profiles of bright OH sky emission lines.
Duration: 4 hours.
Personnel: McGregor, Gemini Instrument Scientist.
Success Criteria: Scattered light is < 10% of the total light entering the NIFS instrument in the spectral bandpass of interest.
4.24 Radial Velocity Stability
Goal: Measure the radial velocity stability.
Procedure: Obtain high signal-to-noise ratio spectra every night for at least two systems with known constant radial velocity or with well-determined radial velocity variations. Bracket these observations with arc lamp spectra obtain less than 1 hr before and after the radial velocity measurement. Determine wavelength calibration via arc lamp and sky emission line spectra. Measure radial velocities of spectral features.
Duration: 8 hours.
Personnel: McGregor, Gemini Instrument Scientist.
Comments: 1. Radial velocities should be accurate to < 5 km s-1 if the flexure requirement (REQ-FPR-0201) is met and radial velocities are referred to arc lamp spectra taken within 1 hr of the science observation.
Success Criteria: RMS radial velocity stability is determined.
4.25 J Band Spectroscopy
Goal: Demonstrate a J band emission line science observation.
Procedure: Record a J band spectrum of H I Pb and [Fe II] 1.257 mm in the inner Narrow Line Region of a Seyfert galaxy with resolved radio structure using ALTAIR.
Duration: 6 hours.
Personnel: McGregor, Gemini Instrument Scientist.
Success Criteria: Spatial-resolved emission-line profiles recorded.
4.26 K Band Spectroscopy
Goal: Demonstrate a K band continuum source science observation.
Procedure: Record a K band spectrum of 2.29 mm CO (2-0) stellar absorption bands in a nearby galactic nucleus or fields in the Galactic Center using ALTAIR.
Duration: 6 hours.
Personnel: McGregor, Gemini Instrument Scientist.
Success Criteria: Stellar velocity dispersion determined down to a radial distance of 0.1².
4.27 Non-ALTAIR Spectroscopy
Goal: Demonstrate a K band science observation without using ALTAIR.
Procedure: Record a J band spectrum of Hα in a z ~ 1 disk galaxy (e.g., Glazebrook et al 1999, MNRAS, 306, 843; see also Moorwood et al. 2000, A&A, 362, 9 for K band spectroscopy at z ~ 2.2). Compare the SNR obtained with the published data.
Duration: 6 hours.
Personnel: McGregor, Gemini Instrument Scientist.
Success Criteria: Non-ALTAIR NIFS compares favorably with published data.
4.28 Occulting Disk Usage
Goal: Define a safe observing procedure using the occulting disks.
Procedure: Slew to a smooth spectrum flux standard. Experiment with procedures for accurately centering the star on the Focal Plane Mask Wheel occulting disks without relying on the NIFS science detector output. This may be achieved by acquiring the science star in the OIWFS then offsetting the star onto the NIFS occulting disk. Slew to a very bright star and use the procedure to measure spectra in the vicinity of the bright occulted star. Measure the intensity of the window ghost image.
Duration: 4 hours.
Personnel: McGregor, Gemini Instrument Scientist.
Comments: 1. Acceptance test for REQ-OCD-0011.
Success Criteria: A procedure for using the occulting disks with minimal remnance is defined. NIFS is able to accurately record data at radii > 0.25² from point sources with K ³ 3 mag.
4.29 Strehl Ratio Degradation
Goal: Measure the degradation in Strehl ratio due to the NIFS optics.
Procedure: Slew to a smooth spectrum flux standard. Record a spectrum of star. Measure the image FWHM and central intensity in the spectrally compressed image. Image the same star with the NIRI high spatial resolution camera. Compare the NIFS and NIRI image parameters.
Duration: 4 hours.
Personnel: McGregor, Gemini Instrument Scientist.
Prerequisites: NIRI mounted on ISS and available for observing.
Success Criteria: Strehl ratio due to the NIFS optics is > 0.80.
4.30 Spectropolarimetry Data Acquisition
Goal: Demonstrate synchronous GPOL data acquisition with NIFS.
Procedure: Perform a spectropolarimetry observation of an object with known polarization degree and orientation. Data acquisition is synchronized with control of the GPOL half-wave plate.
Duration: 4 hours.
Personnel: McGregor, Gemini Instrument Scientist, Jim Hough, Colin Aspin.
Success Criteria: The spectropolarimetry procedure correctly measures polarization degree and orientation.
4.31 Spectropolarimetry Sensitivity
Goal: Determine faint sensitivity limit for NIFS spectropolarimetry.
Procedure: Perform a spectropolarimetry observation of a faint object with known polarization degree and orientation. Measure signal-to-noise ratio achieved. Infer faint limiting magnitude.
Duration: 6 hours.
Personnel: McGregor, Gemini Instrument Scientist, Jim Hough, Colin Aspin.
Success Criteria: Spectropolarimetry sensitivity is quantified and limiting factors identified.
5 Schedule
The Verification and Commissioning tasks are summarized in Table 1. Scheduled access to the telescope is required to execute the plan. The time estimates assume that 8 hr per night (i.e., mid-year) are available for commissioning activities after routine telescope setup and calibration has been performed. This also provides some allowance for imperfect weather conditions.
Table 1: Summary of Verification and Commissioning Tasks
|
Ref. |
Task |
Hours |
Nights |
|
1 |
Initial Field Acquisition |
6 |
0.75 |
|
2 |
Cold Stop Alignment |
4 |
0.50 |
|
3 |
Instrument Focus |
1 |
0.13 |
|
4 |
Instrument Rotator Fiducial |
1 |
0.13 |
|
5 |
Offset From Rotator Axis |
1 |
0.13 |
|
6 |
Pointing Accuracy |
4 |
0.50 |
|
7 |
Image Quality |
4 |
0.50 |
|
8 |
Spatial Pixel Scale |
2 |
0.25 |
|
9 |
Astrometric Accuracy |
4 |
0.50 |
|
10 |
Instrument Flexure |
12 |
1.50 |
|
11 |
System Efficiency |
3 |
0.38 |
|
12 |
Background Brightness |
5 |
0.63 |
|
13 |
Instrumental Sensitivities |
5 |
0.63 |
|
14 |
Bright Limit With ND Filter |
1 |
0.13 |
|
5 |
Highest Obtainable S/N Ratio |
4 |
0.50 |
|
16 |
OIWFS Repeatability |
4 |
0.50 |
|
17 |
OIWFS Offsetting Accuracy |
4 |
0.50 |
|
18 |
OIWFS Responsivity |
3 |
0.38 |
|
19 |
OIWFS Field-Of-View |
3 |
0.38 |
|
20 |
OIWFS Flexure |
10 |
1.25 |
|
21 |
OIWFS Limiting Magnitude |
4 |
0.50 |
|
22 |
Ghost Image Intensity |
4 |
0.50 |
|
23 |
Scattered Light |
4 |
0.50 |
|
24 |
Radial Velocity Stability |
8 |
1.00 |
|
25 |
J Band Spectroscopy |
6 |
0.75 |
|
26 |
K Band Spectroscopy |
6 |
0.75 |
|
27 |
Non-ALTAIR Spectroscopy |
6 |
0.75 |
|
28 |
Occulting Disk Usage |
4 |
0.50 |
|
29 |
Strehl Ratio Degradation |
4 |
0.50 |
|
30 |
Spectropolarimetry Data Acquisition |
4 |
0.50 |
|
31 |
Spectropolarimetry Sensitivity |
6 |
0.75 |
|
|
|
|
|
|
|
TOTAL |
|
17.17 |