Version 1, 2002-Apr-22

1. Background

The purpose of this document is to describe the observatory-specific tasks to be carried out during the DEIMOS commissioning period. The commissioning of DEIMOS is a collaborative effort between the instrument team and the observatory team. Generally speaking, the instrument team will take responsibility for tests which involve instrument characterization, such as astrometric tests, sensitivity tests, etc. This document describes those additional tests which involve the interface between the instrument and the telescope.

The remainder of this document is divided into two main sections. The first, a sequential list, serves as a summary list and notes the order in which the tests are expected to be carried out. It also indicates the estimated time requirements and the priority. The second section is a thematic list gives details on the individual tests. The document concludes with an appendix with sections discussing SKYPA definitions and Considerations Regarding Rotator Calibrations.

2. CARA Engineering Task List - Sequential

The following list indicates the expected order of testing for CARA-related DEIMOS tasks.

Seq.	Test	Priority	Sky Time
High priority - perform during early June commissioning run
1	E1. Initial target acquisition	1	0:30
2	E2. Define REF pointing origin (T667b)	1	0:30
3	F1. Determine TVFLIP	1	0:10
4	F2. Determine TVANGL	1	0:15
5	F3. Determine guider pixel scale	1	0:15
6	I1. Calibrate Rotator Zeropoint	1	0:30
7	H1. Determine INSTFLIP	1	0:20
8	H2. Determine INSTANGL	1	0:10
9	E3. Define SLIT/DEIMOS/FOCUS pointing origins	1	1:30
10	J1. Verify AUTOFOC operation	1	0:30
11	J2. Calibrate Mira	1b	0:10
12	J3. Verify Mira operation	1b	2:00
13	H3. Verify telescope offsetting in instrument coordinates	1b	0:15
Medium priority - perform during or before July commissioning run
14	J4. Calibrate Mira secondary tilt compensations	2	0:30
15	G1. Verify standard guiding modes	2	2:00
16	G2. Verify Reseaux guiding mode	2	TBD
17	K1. Verify operation of facility scripts to offset telescope	2	2:00
18	I2. Verify rotator accuracy/repeatability	2	0:30
19	J7. Test Shack-Hartmann guider focus mask procedure	2	TBD
Lower priority - perform as time permits
20	J5. Verify secondary tilt compensations	3	0:30
21	J6. Determine telescope focus offset for AUTOFOC vs. Mira	3	1:00
22	F4. Characterize guider vignetting	3	0:15
23	I3. Verify rotator tracking performance	3	0:30

3. CARA Engineering Task List - Thematic

Introduction

This section provides detailed information on the tests enumerated in the table above. Tests are grouped within major categories. Organization of the information is very similar to that used for the science team's tests, with minor changes (e.g., observers are always assumed to be CARA staff). The following information is provided for each:

Overview
- Goal: Statement of goals, why needed
- Priority: Task priority code; where:
  - Priority 1 = Highest priority; should be done during early June commissioning run
  - Priority 1b = High priority; should be done during June commissioning runs
  - Priority 2 = Medium priority; perform no later than July engineering run
  - Priority 3 = Lower priority; can be completed later, if needed
- Product: Results to be provided
- Data: On-sky data that will be taken and analyzed
Observing script
- Target: Target IDs, coordinates, finding charts if needed
- Observing log: number of images, instrument settings, exposure times
- Procedure: Observing instructions; sequence of operations
- Sky time: Estimated time needed to execute this program, in HH:MM format.
- Requirements: Observing prerequisites: e.g., sky conditions, seeing, rotator mode, any parts of the instrument that DON'T need to be working, airmass/atmospheric dispersion constraints
- Calibrations: Associated instrument calibration data and instructions for taking them (flats, wavelength calibrations, twilights, etc.)
- Notes: Any other information needed by the observers
Analysis
- Timescale: Timescale for data reduction
- Procedure: Steps in the data reduction
- Software: Software tools needed, including
  - Existing packages
  - New tools that need to be written
End products: Lists reports and stuff to be produced
Status: Gives the completion status of the test. Typical stages will be include:
- To be scheduled
- Scheduled
- Observing in progress
- Observing completed
- Analysis in progress
- Analysis completed
- Results posted

Summary

E. Pointing Tests
F. Guide Camera Tests
G. Autoguider Tests
- G1. Verify standard guiding modes
- G2. Verify Reseaux guiding mode
H. DCS Tests
I. Rotator Tests
J. Focusing Tests

E. Pointing Tests

E1. Initial target acquisition

Overview
- Goal: Verify initial pointing by putting a target onto the center of the guider
- Priority: 1
- Product: Rough coordinates of REF pointing origin in the telescope focal plane
- Data: None
Observing script
- Target: Any prominent Galactic globular cluster or other extended object with a well-defined gradient to lead us toward the center, OR a bright (V=3) star with PMFM=1000
- Observing log: None (no exposures required)
- Procedure:
  1. Set the instrument rotator to PA mode at 0°.
  2. Bring up the DCS GUI pointing origin window and enter the approximate coordinates of the REF pointing origin.
  3. For rough pointing check, select and point to a globular cluster OR bright star, and send to REF pointing origin.
  4. If using a bright star, put 1000nm of PMFM into primary.
  5. Set handle paddle to "Adjust Pointing Origin" mode and use it to adjust the position of the REF pointing origin until object is centered on the guider pickoff mirror.
  6. Have OA set pointing.
  7. Change the rotator angle by 90° and verify that the object remains in the same position (roughly --- we expect some movement because REF is still defined only roughly).
  8. For fine alignment, select and point to any reasonably bright star send to the nominal REF pointing origin for DEIMOS (center of the pickoff mirror).
  9. If necessary, center using the hand paddle.
  10. Have OA set pointing.
  11. Check pointing using 2-3 nearby GSC target stars.
- Sky time: 0:30
- Requirements: Partially clear skies; approximate coordinates of REF from Vern Wallace
- Calibrations: None
- Notes: A globular makes a good target; it's easier to tweak up pointing on than bright stars or other types of fields -- you hopefully can distinguish a gradient in the star density. Also possible is to use a bright star with the segments splayed out using PMFM=1000.
Analysis
- Timescale: Immediate
- Procedure: N/A
- Software: None
End products: TBD
Status: To be scheduled

E2. Define REF pointing origin (T667b)

Overview
- Goal: Define the position at which target stars should appear on the guider
- Priority: 1
- Product: Accurate coordinates of REF pointing origin in the telescope focal plane
- Data: None
Observing script
- Target: Any moderately bright star
- Conditions: Partially clear skies
- Prerequisites: Determine TV guider pixel position at which stars should be centered (nominally the pixel center of the pickoff mirror region?)
- Observing log: N/A
- Procedure:
  1. [OA] Acquire GSC star and send to REF pointing origin. It should be nearly centered on the guider. Begin guiding.
  2. Bring up the DCS GUI pointing origin window.
  3. [OA] On XGUIDE, set "Adjust pnt origin using ADJ PNT/GOTO" to "no".
  4. [OA] Adjust collimation by pressing the "Adjust Pointing" button on Xguide.
  5. Note the current REF X and Y coordinates.
  6. [OA] Halt guiding. Immediately drive the rotator through plus or minus 180° and wait until it is once again tracking. Resume guiding.
  7. [OA] On XGUIDE, set "Adjust pnt origin using ADJ PNT/GOTO" to "yes".
  8. [OA] Immediately adjust pointing origin.
  9. Note the current REF X and Y.
  10. Calculate the average of the (X,Y) readings from steps 5 and 9. Type the resulting position into the DCS GUI pointing origin window under REF and click "Define".
  11. Repeat steps 3-10 time permitting, until you have made four adjustments to the pointing origin (i.e. until you have, in total, driven from 0 -> -180 -> 0 -> -180 -> 0). Even a single iteration is useful though.
  12. Adjust collimation and save pointing origins and mark and save collimations.
  13. On XGUIDE, set "Adjust pnt origin using ADJ PNT/GOTO" to "no".
- Sky time: 0:30
- Calibrations: None
- Notes:
Analysis
- Timescale: Immediate
- Procedure: See above
- Software: None
End products: TBD
Status: To be scheduled

E3. Define SLIT/DEIMOS/FOCUS pointing origins

Overview
- Goal: Define the focal plane positions of the longslit center, imaging FOV center, and telescope focus (Mira) position relative to the REF pointing origin.
- Priority: 1
- Product: Accurate focal plane coordinates of the specified pointing origins
- Data: None
Observing script
- Target: Any moderately bright star
- Conditions: Partially clear skies
- Prerequisites:
  - Define the REF pointing origin (Test E2).
  - Determine DEIMOS imaging pixel positions corresponding to longslit center, imaging center, focus position.
  - Algorithm to convert from pixel offsets to focal plane offsets.
- Observing log: N/A
- Procedure:
  1. Point to a sparse star field at which the ROTPPOSN will be changing very slowly while in PA (position angle) rotator mode. For example, try near dec=+50 and at least 1 hour AWAY from the meridian.
  2. Put the rotator into PA mode. Do not guide.
  3. Rough Alignment:
    - Find a relatively bright and isolated star (mag < 13) and center it on REF.
    - Select the pointing origin of interest (SLIT, DEIMOS, FOCUS).
    - Bring up the handpaddle in "pointing origin" adjustment mode. Use this to offset the star onto the imaging field of view.
    - Take a DEIMOS image and locate the star.
    - If star is more then 100 px from the desired pixel position, use the handpaddle to make an appropriate offset in the pointing origin and return to previous step.
  4. Fine Alignment:
    - Acquire a DEIMOS image
    - Locate the alignment star and measure a centroid (x1, y1)
    - Rotate the instrument by 180°
    - Acquire a DEIMOS image
    - Locate the alignment star and measure a centroid (x2, y2)
    - Compute the averages xc=0.5*(x1+x2) and yc=0.5*(y1+y2)
    - Compute the error dx=x-xc and dy=y-yc, where (x,y) is the desired pixel position
    - Convert the error to a change in focal plane position using the appropriate algorithm
    - Compute the new pointing origin coordinates based on these errors
    - Have the OA enter these values into the DCS GUI and verify that the telescope moves appropriately.
    - Repeat loop until convergence is achieved.
- Sky time: 1:30 (0:30 per)
- Calibrations: None
- Notes:
Analysis
- Timescale: Immediate
- Procedure: None
- Software: Need algorithm to convert pixel offset to focal plane coordinate offset
End products: TBD
Status: To be scheduled

F. Guide Camera Tests

F1. Determine TVFLIP

Overview
- Goal: Determine the handedness of the DEIMOS guider FOV
- Priority: 1
- Product: TVFLIP value
- Data: None
Observing script
- Target: Any reasonably bright star
- Conditions: Partially clear skies
- Prerequisites: None
- Observing log: N/A
- Procedure:
  1. Note the orientation of the tkrose for the guider. If the azimuth arrow points 90 degrees CLOCKWISE from the elevation arrow, this will be called left-handed. If it is 90 degrees COUNTERCLOCKWISE this will be called righthanded.
  2. Move the telescope in elevation by -10 arcsec. The star will move along the positive elevation direction.
  3. Move the telescope in azimuth by -10 arcsec. The star will move along the positive azimuth direction.
  4. Compare the observed handedness with the tkrose handedness. If they differ, use "show -s dcs tvflip" to check the current handedness, and change it.
- Sky time: 0:10
- Calibrations: None
- Notes: If you have to modify TVFLIP, you must reselect the instrument, kill and restart the tkrose.
Analysis
- Timescale: Immediate
- Procedure: None
- Software: None
End products: TBD
Status: To be scheduled

F2. Determine TVANGL

Overview
- Goal: Determine the sense of rotation for the TV guider.
- Priority: 1
- Product: TVANGL value
- Data: None
Observing script
- Target: Any reasonably bright star
- Conditions: Partially clear skies
- Prerequisites: None
- Observing log: None
- Procedure: TBD
- Sky time: 0:15
- Calibrations: None
- Notes: Requires input from Al Conrad
Analysis
- Timescale: Immediate
- Procedure: N/A
- Software: None
End products: TBD
Status: To be scheduled

F3. Determine guider pixel scale

Overview
- Goal: Measure the approximate pixel scale of the DEIMOS guider
- Priority: 1
- Product: Number of arcsec/px in guider X and Y coordinates
- Data: 4 guider frames
Observing script
- Target: Isolated m=15 star
- Conditions: Partially clear, stable seeing
- Prerequisites: None
- Observing log:
  - 1 TV image at +30, +30
  - 1 TV image at +30, -30
  - 1 TV image at -30, -30
  - 1 TV image at -30, +30
- Procedure:
  1. Acquire isolated star and center on guider
  2. DISABLE guiding; guider offset require knowledge of pixel scale, and hence guiding could bias the results
  3. Set guider binning to 1x1
  4. Rotate instrument such that north is up (and thus that RA/Dec offsets will be along columns/rows)
  5. Save a fullframe guider image and verify that target is well exposed but not saturated. Modify guider integration time or select new target as needed.
  6. Offset telescope to (+30,+30) arcsec and save exposure
  7. Offset telescope to (+30,-30) arcsec and save exposure
  8. Offset telescope to (-30,-30) arcsec and save exposure
  9. Offset telescope to (-30,+30) arcsec and save exposure
  10. Offset telescope to (+30,+30) arcsec and save exposure
- Sky time: 0:15
- Calibrations: None
- Notes: Because we are unguided, this test is best done at a location where the rotator is stationary and the star's movement on the sky is small; for example, on the meridian at dec=+50°. Need to ask software folks how this information is incorporated into the guider software to perform offsets.
Analysis
- Timescale: 10 minutes
- Procedure:
  1. Compute the change in guider (X,Y) between consecutive guider images
  2. Divide known offset of 60 arcsec by the measured dX or dY to derive plate scale in arcsec/px
  3. Average scale_X and scale_Y values to derive results.
- Software:
  - Use IRAF imexamine to derive accurate centroids
End products: TBD
Status: To be scheduled

F4. Characterize guider vignetting

Overview
- Goal: Investigate vignetting in the DEIMOS guider
- Priority: 3
- Product: Diagram of vignetting vs. pixel position on the guider
- Data: Series of guider images taken in PMFM mode at various locations on the guider
Observing script
- Target: Isolated, m=12 star
- Conditions: Partially clear skies
- Prerequisites: None
- Observing log:
- Procedure:
  1. Acquire isolated star
  2. Center star on guider
  3. Set binning to 2x2
  4. Set PMFM to +500
  5. Observe whether all 36 segments are visible
  6. Offset star to corner of pickoff mirror and check 36 segments; save cam image if desired
  7. Check the other 3 corners to verify no vignetting
  8. Check other locations only if vignetting is found
- Sky time: 0:15
- Calibrations: None
- Notes:
Analysis
- Timescale: Immediate
- Procedure: N/A
- Software: None
End products: TBD
Status: To be scheduled

G. Autoguider Tests

G1. Verify standard guiding modes

Overview
- Goal: Check that guiding in the following common guiding modes works as expected:
  1. Position-angle mode
  2. Vertical-angle mode (off slit)
  3. Stationary mode (off slit)
- Priority: 2
- Product: N/A
- Data: None
Observing script
- Target: Pair of m=15 stars, well-separated on DEIMOS guider
- Conditions: Partially clear
- Prerequisites: None
- Observing log: N/A
- Procedure:
  1. Position-angle mode
    1. Acquire high-elevation (>80°) m=15 star pair on guider, slightly east of meridian (HA=0:15)
    2. Set rotator to any angle, position angle mode
    3. Begin guiding on one of the stars
    4. Save cam images regularly for 0:30 while target transits
    5. Verify that stars do not change pixel position on guider
  2. Vertical-angle mode (offset/DIFF mode)
    1. Acquire high-elevation (>80°) m=18 star on guider, slightly east of meridian (HA=0:15)
    2. Set rotator to parallactic angle, vertical angle mode
    3. Insert longslit
    4. Send object to slit
    5. Select object location (on slit) and guide star (on pickoff mirror); set hfudge parameters appropriately
    6. Remove longslit
    7. Acquire DEIMOS image
    8. Monitor guider or instrument compass rose and verify that slit remains parallel to elevation axis while rotation relative to (N,E) coordinates
    9. Take DEIMOS images every 5 minutes for 0:30
    10. Analyze images to verify that star did not move during interval
  3. Stationary mode (offset/DIFF mode)
    1. Similar to vertical-angle mode procedure, except set rotator mode to "stationary" and set hfudge parameters appropriate for stationary mode
    2. Monitor guider or instrument compass rose and verify that roses rotate while telescope tracks through meridian.
    3. Analyze images to verify that star did not move during interval
- Sky time: 2:00
- Calibrations: None
- Notes: Pointing origins and rotator must be calibrated before attempting this test
Analysis
- Timescale: Next day
- Procedure: See above
- Software:
  1. IRAF imexamine task to measure star positions
End products: TBD
Status: To be scheduled

G2. Verify Reseaux guiding mode

Overview
- Goal: Check whether Reseaux guiding mode works as expected
- Priority: 1b
- Product: TBD
- Data: TBD
Observing script
- Target: TBD
- Conditions: Partially clear skies
- Prerequisites: None
- Observing log: TBD
- Procedure: TBD
- Sky time: TBD
- Calibrations: None
- Notes:
Analysis
- Timescale: TBD
- Procedure: TBD
- Software: TBD
End products: TBD
Status: To be scheduled

H. DCS Tests

H1. Determine INSTFLIP

Overview
- Goal: Determine handedness of DEIMOS images
- Priority: 1
- Product: INSTFLIP value
- Data: TBD
Observing script
- Target: Isolated m=15 star
- Conditions: Partially clear skies
- Prerequisites: None
- Observing log: TBD
- Procedure: TBD
  1. Note the orientation of the tkrose for the instrument. If the azimuth arrow points 90 degrees CLOCKWISE from the elevation arrow, this will be called left-handed. If it is 90 degrees COUNTERCLOCKWISE this will be called right-handed.
  2. Acquire star on guider and send to DEIMOS pointing origin
  3. Mark base
  4. Acquire a DEIMOS image
  5. Move the telescope in elevation by -10 arcsec
  6. Acquire a DEIMOS image. The star will have moved along the positive elevation direction. Mark this vector on the display.
  7. Go to base
  8. Move the telescope in azimuth by -10 arcsec.
  9. Acquire a DEIMOS image. The star will move along the positive azimuth direction. Mark this vector on the display
  10. Compare the observed handedness with the tkrose handedness. If they differ, use "show -s dcs instflip" to check the current handedness, and change it.
  11. If needed, restart the tkrose and verify that the handedness is now correct.
- Sky time: 0:20
- Calibrations: None
- Notes:
Analysis
- Timescale: Immediate
- Procedure: See above
- Software: None
End products: TBD
Status: To be scheduled

H2. Determine INSTANGL

Overview
- Goal: Calibrate the rotation of the instrument detector relative to the rotator zeropoint
- Priority: 1
- Product: INSTANGL value
- Data: n/a
Observing script
- Target: V=15 star
- Conditions: Partially clear
- Prerequisites: Rotator must be properly zeropointed relative to the slitmask
- Observing log: TBD
- Procedure:
  1. Set INSTANGL to 90°
  2. Acquire star and send to DEIMOS pointing origin.
  3. Acquire a guide star near the field center and begin guiding
  4. Mark base coordinates
  5. Save a DEIMOS image, measure star location (x1,y1)
  6. Move telescope 60 arcsec in instrument X coordinates using the command "mx 60"
  7. Save a DEIMOS image, measure star location (x2,y2)
  8. If the star "moved" to the left; angle is okay. If the star moved to the "right", change INSTANGL to -90° and repeat test. If star moved another direction, there is a problem...
- Sky time: 0:10
- Calibrations: None
- Notes:
Analysis
- Timescale: Immediate
- Procedure: See above
- Software: None
End products:
Status: To be scheduled

H3. Verify telescope offsetting in instrument coordinates

Overview
- Goal: Verify that telescope moves performed in the instrument coordinate system produce the desired direction and magnitude
- Priority: 1b
- Product: n/a
- Data: DEIMOS direct images
Observing script
- Target: V=15 star
- Conditions: Partially clear
- Prerequisites: Rotator and INSTANGL must be calibrated
- Observing log: TBD
- Procedure:
  1. Acquire star and send to DEIMOS pointing origin.
  2. Acquire a guide star near the field center and begin guiding
  3. Mark base coordinates
  4. Save a DEIMOS image, measure star location (x1,y1)
  5. Move 60 arcsec in instrument X coordinates
  6. Save a DEIMOS image, measure star location (x2,y2)
  7. Go to base coordinates
  8. Save a DEIMOS image, measure star location (x1,y1)
  9. Move 60 arcsec in instrument Y coordinates
  10. Save a DEIMOS image, measure star location (x2,y2)
- Sky time: 0:15
- Calibrations: None
- Notes:
Analysis
- Timescale: Immediate
- Procedure:
  1. Verify that star moves are purely in (x) or (y) as appropriate.
- Software:
  - IRAF imexamine to measure star centers
End products:
Status: To be scheduled

I. Rotator Tests

I1. Calibrate Rotator Zeropoint

Overview
- Goal: Zeropoint the rotator based on the orientation of the DEIMOS slitmask plane.
- Priority: 1
- Product: ROTBASE value
- Data: Trailed star images
Observing script
- Target: Equatorial star field on the meridian
- Conditions: Clear skies
- Prerequisites: None
- Observing log:
  1. 5×100s trailed star images
  2. 60s image of pinhole grid mask illuminated by sky
- Procedure:
  1. Point the telescope to (AZ, EL) = (180,70), mount coordinates. Set the rotator to 0° (??), stationary mode, so that stars trail along the long side of the array.
  2. Configure DEIMOS for imaging.
  3. Set exposure time to 100 s. The images will thus contain vertical trails of stars exposed as the world turns.
  4. Take 5 exposures; examine each image for the quantity and quality of star trails. We require a few trails in at least 2 images with signal at least 200 counts above background, separated by about 100 pixels from neighboring trails of high signal, preferably located within the central 1000 column region. If conditions are not clear enough to meet the signal requirement for even 1 star trail, then abort the test in favor of clearer conditions later. Note also that observations made at LST=1:00 or 13:00 will be near the galactic poles and hence unlikely to contain sufficient density of stars.
  5. Insert grid of holes mask. Enable tracking to prevent trailed stars on pinholes. Take 1 60s exposure to define the rotation of the detector relative to the slitmask.
Sky time: 0:30
Calibrations: None
Notes:

Analysis

Timescale: Immediate
Procedure:
1. Process images to remove overscan, trim, convert to flatspace
2. Measure the skew of star trails relative to the CCD columns
3. Measure the skew of slitmask holes relative to the CCD columns
4. Convert the angular offset between star trails and slitmask angle into a correction to the ROTBASE keyword
Software:
1. IDL routines to debias DEIMOS images
2. IDL routine to analyze angle of star trails and output new ROTBASE value

End products: TBD

Status: To be scheduled

I2. Verify rotator accuracy/repeatability

Overview
- Goal: Characterize the ability of the DEIMOS rotator to rotate accurately
- Priority: 2
- Product: Repeatability of rotator angles
- Data: Star trail images at various rotator angles
Observing script
- Target: Equatorial starfield at meridian
- Conditions: Clear
- Prerequisites: Rotator must be calibrated
- Observing log: TBD
- Procedure:
  1. Point the telescope to (AZ, EL) = (180,70), mount coordinates. Set the rotator to 0° (??), stationary mode, so that stars trail along the long side of the array.
  2. Reduce rotator angle by 90° increments as many times as allowed by the rotator limits.
  3. Configure DEIMOS for imaging.
  4. Set exposure time to 100 s. The images will thus contain vertical trails of stars exposed as the world turns.
  5. Acquire DEIMOS exposures until at least one good star trail is achieved.
  6. Increase the rotator angle by 90° and acquire more star trail images.
  7. Repeat until no more 90° increments are possible
- Sky time: 0:30
- Calibrations: None
- Notes:
Analysis
- Timescale: Few days
- Procedure:
  1. Measure star trail angles on images and verify that as the rotator moves by 90°', the star trails also rotate by 90°
- Software: TBD
End products: TBD
Status: To be scheduled

I3. Verify rotator tracking performance

Overview
- Goal: Characterize the quality of tracking by the rotator by taking images in position angle mode during transit
- Priority: 3
- Product: Measurement of rotator tracking accuracy
- Data: Images of rich star field during transit
Observing script
- Target: A rich star field at declination in the range 15-17° dec or 23-25°
- Conditions: Clear with good seeing (<1 arcsec)
- Prerequisites: None
- Observing log: TBD
- Procedure:
  - Set up DEIMOS for imaging
  - Acquire rich star field 20 minutes east of meridian and send to DEIMOS pointing origin
  - Acquire guide star and begin guiding in PA mode
  - Take 30s DEIMOS images every minute starting 0:10 before transit and continuing until 0:10 after transit
- Sky time: 0:30
- Calibrations: None
- Notes:
Analysis
- Timescale: Few days
- Procedure: Measure the rotational smearing of star images at the edges of the image and derive limits on telescope tracking accuracy.
- Software: TBD
End products: TBD
Status: To be scheduled

J. Focusing Tests

J1. Verify AUTOFOC operation

Overview
- Goal: Determine that AUTOFOC works properly to focus the telescope on the longslit, and compare results obtained with star on pickoff mirror vs. star on longslit.
- Priority: 1
- Product: n/a
- Data: Sequence of guider images at various secondary piston settings
Observing script
- Target: Isolated V=12 star
- Conditions: Clear and stable
- Prerequisites: REF pointing origin defined
- Observing log: n/a
- Procedure:
  1. Acquire star in guider and send to REF pointing origin
  2. Note the starting value of TELFOC keyword
  3. Save guider image and measure starting image quality
  4. Execute the AUTOFOC procedure to focus star on guider pickoff mirror
  5. Note the revised value of TELFOC
  6. Save guider image and measure ending image quality
  7. Send star to the SLIT pointing origin and move it off the slit
  8. Increase exposure time as needed to obtain a usable image of the star
  9. Execute the AUTOFOC procedure to focus star on longslit area
  10. Note the revised value of TELFOC
  11. Save guider image and measure ending image quality
- Sky time: 0:30
- Calibrations: None
- Notes:
Analysis
- Timescale: Immediate
- Procedure: Automated
- Software: AUTOFOC analysis tool
End products: TBD
Status: To be scheduled

J2. Calibrate Mira

Overview
- Goal: Obtain the measurements needed to program the Mira software for operation with DEIMOS
- Priority: 1b
- Product: Handedness of DEIMOS images and approximate pixel scale
- Data: Series of direct images taken in PMFM mode using DEIMOS
Observing script
- Target: V=12 star
- Conditions: Partially clear
- Prerequisites: DEIMOS pointing origin must be defined
- Observing log: TBD
- Procedure:
  1. Acquire star on guider and send to DEIMOS pointing origin
  2. Set PMFM to +500
  3. Configure DEIMOS for direct imaging
  4. Save a DEIMOS image; note SKYPA and ROTPPOSN
  5. Rotate DEIMOS by 45°
  6. Save a DEIMOS image; note SKYPA and ROTPPOSN
- Sky time: 0:10
- Calibrations: None
- Notes:
Analysis
- Timescale: 1 day
- Procedure: TBD
- Software: TBD
End products: TBD
Status: To be scheduled

J3. Verify Mira operation

Overview
- Goal: Run Mira on DEIMOS to verify and optimize operation. Vary the initial conditions (secondary tilt, rotator position) to ascertain whether proper corrections are achieved. focuses the telescope with DEIMOS
- Priority: 1b
- Product: Varies
- Data: DEIMOS images taken in PMFM mode
Observing script
- Target: Isolated V=12.5 star
- Conditions: Clear, stable
- Prerequisites: Mira must be calibrated
- Observing log: TBD
- Procedure: TBD
- Sky time: 2:00
- Calibrations: None
- Notes:
Analysis
- Timescale: 1 day
- Procedure: TBD
- Software: Mira tool
End products: TBD
Status: To be scheduled

J4. Calibrate Mira secondary tilt compensations

Overview
- Goal: Calibrate the telescope secondary mirror tilt corrections required to put the secondary in the on-axis position, as a function of the physical instrument rotator position angle.
- Priority: 1
- Product: Model for Theta_x and Theta_y secondary mirror corrections vs. ROTPPOSN
- Data: Series of images acquired in PMFM mode vs. ROTPPOSN
Observing script
- Target: V=12.5 star at a sky location with slowly changing parallactic angle (az=270, el=75?)
- Conditions: Clear, stable
- Prerequisites: DEIMOS pointing origin defined
- Observing log: TBD
- Procedure:
  1. Configure DEIMOS for imaging
  2. Set instrument rotator to negative limit
  3. Acquire star and send to DEIMOS pointing origin
  4. Set PMFM to +500
  5. Subwindow detector as appropriate
  6. Acquire 10-second exposure
  7. Rotate instrument by +30°
  8. Repeat previous two steps through 540° of rotation
- Sky time: 0:30
- Calibrations: None
- Notes:
Analysis
- Timescale: 1 week
- Procedure: TBD
- Software:
  - Mira
  - Custom IDL analysis routines developed for LRIS
End products: TBD
Status: To be scheduled

J5. Verify secondary tilt compensations

Overview
- Goal: Check that the secondary tilt compensations for DEIMOS correctly place the telescope secondary on-axis.
- Priority: 3
- Product: Coma vs. ROTPPOSN plot
- Data: DEIMOS images taken in PMFM mode at various rotator angles
Observing script
- Target: V=12.5 star at a sky location with slowly changing parallactic angle (az=270, el=75?)
- Conditions: Clear, stable
- Prerequisites: Secondary corrections calibrated and put into Mira
- Observing log: TBD
- Procedure:
  1. Configure DEIMOS for imaging
  2. Set instrument rotator to negative limit
  3. Acquire star and send to DEIMOS pointing origin
  4. Run Mira at least twice, sending rotator coma corrections (i.e., click "spectroscopic mode" button on Mira when sending corrections), until solution converges
  5. Set PMFM to +500
  6. Subwindow detector as appropriate
  7. Acquire 10-second exposure
  8. Rotate instrument by +30°
  9. Repeat previous two steps through 540° of rotation
- Sky time: 0:30
- Calibrations: None
- Notes: These data can also be analyzed to measure the secondary mirror decentering.
Analysis
- Timescale: 1 week
- Procedure:
  1. Analyze images using Mira; obtain theta_x, theta_y corrections
  2. Plot the correction vectors and verify that they are all near zero
- Software: Mira
End products: TBD
Status: To be scheduled

J6. Determine offset from AUTOFOC to Mira

Overview
- Goal: Measure the difference between secondary focus measured using Mira and AUTOFOC.
- Priority: 3
- Product: Delta(TELFOC)
- Data: PMFM and autofoc images
Observing script
- Target: V=12.5 and V=15 stars at a place where rotator and elevation are changing slowly
- Conditions: Clear and stable with decent seeing (1 arcsec or better)
- Prerequisites: Mira calibrated
- Observing log: TBD
- Procedure:
  1. Configure DEIMOS for R-band imaging
  2. Disable temperature and elevation corrections to secondary focus
  3. Acquire V=12.5 star
  4. Run MIRA, send moves
  5. Repeat MIRA to verify solution
  6. Acquire V=15 star
  7. Run AUTOFOC, note but do NOT send moves
  8. Acquire V=12.5 star
  9. Run MIRA, note but do NOT send moves
  10. Acquire V=15 star
  11. Run AUTOFOC, note but do NOT send moves
  12. Repeat as needed until a well-defined delta(TELFOC) is determined
  13. Enable temperature and elevation corrections to secondary focus
- Sky time: 1:00
- Calibrations: None
- Notes: Want rotator position relative to secondary mirror nearly constant in order to prevent confusion due to rotator-dependent focus and come corrections. Want elevation slowly-changing in order to prevent confusion with elevation-dependent corrections.
Analysis
- Timescale: Immediate
- Procedure: Self-evident
- Software: None
End products: TBD
Status: To be scheduled

J7. Test Shack-Hartmann guider focus mask procedure

Overview
- Goal: Verify feasibility and refine Shack-Hartmann mask method for focusing telescope
- Priority: 2
- Product: Procedure for focusing telescope using guider Shack-Hartmann masks
- Data: Guider images acquired with Shack-Hartmann masks
Observing script
- Target: TBD
- Conditions: Clear, good and stable seeing
- Prerequisites: TBD
- Observing log: TBD
- Procedure: TBD
- Sky time: TBD
- Calibrations: TBD
- Notes: This method depends on the stability of the guider focus, which should probably be tested separately.
Analysis
- Timescale: TBD
- Procedure: TBD
- Software: TBD
End products: TBD
Status: To be scheduled

K. Miscellaneous Tests

K1. Verify operation of facility scripts to offset telescope

Overview
- Goal: verify proper operation of all scripts which can't be completely testing during daytime, including those that:
  - Perform offsets in detector arcsec c.s.
  - Perform offsets in detector pixel c.s.
  - Perform offsets in guider pixel c.s.
  - Perform offsets in guider arcsec c.s.
  - Perform offsets in RA/DEC c.s.
  - Perform offsets in az/el c.s.
  - Dither objects along slit
- Priority: 2
- Product: n/a
- Data: n/a
Observing script
- Target: V=15 star
- Conditions: Partially clear
- Prerequisites: INSTANGL, ROTBASE, TVANGL, etc., calibrated
- Observing log: TBD
- Procedure:
  1. Acquire star and send to guider
  2. Take starting image
  3. Execute script to move telescope
  4. Take ending image
  5. Continue as required until script is completed
- Sky time: 2:00
- Calibrations: None
- Notes:
Analysis
- Timescale: n/a
- Procedure: n/a
- Software: n/a
End products: TBD
Status: To be scheduled

Appendix

SKYPA Definitions

Keck instruments generally have multiple sky position angles defined. The fundamental definition of the sky position angle (SKYPA) is the angle between celestial north and the guider YIM axis. As with LRIS, this direction will be approximately perpendicular to the direction which is of most interest to observers, that of the slit. Accordingly, the sky position angle which will be saved in the image headers and displayed on FACSUM will not be the fundamental sky position angle as defined in KSD 40.

The following SKYPA options are proposed for DEIMOS:

Name	Description	Offset* [°]
SKYPA0	Long slit	+90
SKYPA1	Guider column (YIM)**	0
SKYPA2	Up on science detector***	0

Notes:

*Offsets are approximate and are expressed relative to the fundamental SKYPA, SKYPA1
**This is the fundamental SKYPA (i.e., the one displayed on FACSUM and saved in image headers as keyword ROTPOSN) and has zero offset by definition
***The DEIMOS science detector consists of 8 separate CCDs with slightly different physical orientations; hence, we must identify the detector which is to serve as the reference for this SKYPA. Logically, this should also be the CCD on which the DEIMOS pointing origin lies.

Considerations Regarding Rotator Calibrations

According to KSD 40, guider YIM shall define the rotator angle and hence the fundamental SKYPA, SKYPA1. However, the guider is neither the most stable not the most astronomically important element in the focal plane: the slitmask mechanism is of greater utility. This suggests the following plan for achieving rotational alignment of the focal plane systems:

The longslit orientation shall form the basis of alignment in the focal plane.
The CCD dewar (or, more likely, a chosen CCD within the dewar) shall be adjusted rotationally until it is well aligned with the slitmask.
The TV guider detector shall be adjusted rotationally until it is well aligned with the slitmask.

This suggests the following order of operations to define DCS parameters:

Set TVFLIP appropriately for guider image
Set TVANGL to 0° or 180°
Set ROTZERO to produce images aligned to TV guider rows/columns
Re-init rotator
Adjust ROTBASE keyword value to produce images aligned precisely to CCD rows/columns
Set INSTANGL to +90° or -90° and verify operation