Synopsis

• Preliminaries
  1. Launch SAT
  2. Focus telescope
  3. Configure DEIMOS
• Coarse Alignment
  1. Select Guider Coarse Align tab
  2. Select target
  3. Acquire target; verify the following:
     • Target name and coordinates
     • Position angle (skypa)
     • Pointing origin (should be DEIMOS)
  4. Click Grab guider image
  5. Click on a well exposed star to compute offset
  6. Click Move Telescope
  7. Repeat steps 4-6 until aligned
• Fine Alignment
  1. Select Fine Align tab
  2. Click Start fine alignment
  3. Wait for image and analysis to complete
  4. Review fits; reject bad stars
  5. Review and send telescope/rotator moves
  6. Repeat steps 3-5 until no moves required
  In the case the Fine Align procedure does not converge, you can use the alternative Imaging Coarse Align procedure.
• Acquire Spectra .
  1. Click Go Back to restore grating to science wavelength
  2. Select Spectral CCD readout mode
  3. Set exposure time
  4. Click update CCD
  5. Execute wffcs ; goi
  6. Confirm exposure starts

Preliminaries

1. Launch SAT.
   • Navigate to an “analysis” VNC desktop (blue background)
   • From the window manager pull-down menu select

     	DEIMOS Utilities -> Slitmask Alignment Tool

   • Click Load Star List, locate the appropriate directory, and select the appropriate starlist file.
2. Focus telescope.
   • In the MAGIQ UI, middle click on your next target.
   • Ask to OA to run Mira in the neighborhood of your target. If you'll be on the field for several hours, then have the OA focus 1-2 hours west of the field.
   • Wait about 10 minutes for the OA to acquire an appropriate star and run Mira.
3. Configure DEIMOS.
   • Insert desired slitmask. You can do this while the telescope slews.
   • Send grating to zeroth-order position by clicking the GO ZERO button on the DEIMOS Dashboard GUI's grating subpanel.

Coarse Alignment

1. Select coarse align tab. Click the Guider Coarse Align tab on the SAT.
2. Select target. Click the Target selector and choose your next target from among the options on the list. The tool will download and display the DSS image corresponding to the DEIMOS guider FOV and will mark the locations of any stars listed in the Guide Star Catalog.
3. Acquire target. When the OA tells you that your target is on DEIMOS, check the following information on FACSUM to verify that your position is correct:
   • Target name and coordinates
   • Position angle (skypa)
   • Pointing origin (should be DEIMOS)
4. Grab guider image. Click the Grab Guider Image button, which will:
   • trigger MAGIQ to save a guider image
   • display the guider image on the right-hand pane
5. Select fiducial. Identify the same star in the two guider images:
   • Compare the guider image (right pane) to the corresponding DSS image (left pane). You should easily identify stars in common; if not, re-confirm RA/Dec, position angle, and pointing origin.
   • Adjust the brightness and contrast if necessary by right clicking on the image and dragging the mouse.
   • Click on an object in the guider image (at right). The SAT will then:
     • compute the center of the target;
     • mark the object with a yellow box;
     • draw a yellow box around the corresponding star in the DSS image pane;
     • compute and display the telescope move required to shift the guider image to align with the DSS image.
   • If the highlighted DSS star is not correct, select a different star by either clicking in the DSS image on the appropriate star or selecting the star in the guide star list.
6. Move telescope. Click the Move Telescope button to:
   • offset the telescope;
   • acquire and display a new guider image at the updated position.
7. Iterate. If the new guider image in the right pane does not have the stars well centered in the red boxes, repeat the preceding steps to re-measure the center and apply another move.

Fine Alignment

1. Select fine align tab. Click the Fine Align tab on the SAT.
2. Start fine alignment. Click the Start Fine Alignment button. The software will then:
   • configure DEIMOS for direct imaging mode by moving the grating to zeroth order;
   • acquire an image;
   • read and analyze the image;
   • display object and box profile fits;
   • calculate offsets in translation and rotation;
   • suggest telescope moves by preselecting Y/N for X/Y-inst and Rotation.
   It is important not to update the CCD parameters in the Dashboard GUI while the fine alignment is in process. If the CCD parameters are updated in the Dashboard GUI, they will will override the default SAT configuration and the alignment process will fail.
3. Review fits. Review the object and box fits, calculated offsets, and move recommendations. For each star, the SAT graphs:
   • X fit to the stellar and box profile;
   • Y fit to the stellar and box profile;
   • residual fit to the object position in the Residual Map.

   XYFIT codes

   Graphic	Description
   white solid line	star and box profile
   vertical white dotted line	fitted object peak intensity
   green box	shows centering of the fitted box
   blue dashed line	estimated sky level

4. Reject bad stars. If necessary, exclude a star from the fit by clicking the corresponding checkbox beside the X/Y cuts. Some possible reasons to remove a star from the fit are:
   • The white dotted line is not at the stellar peak.
   • No object is visible in the box.
   • The residual is much greater than for the other targets, indicating bad astrometry for the alignment star.
   When you exclude a star from the fit, the corrections will be recalculated with that object ignored. Please see the sample image of a star excluded from the fit.
5. Review moves. If you want to override the default move recommendation, click the Y or N button next to the offset.
6. Send moves.
   • If no moves are recommended, then your mask is sufficiently well aligned for science' proceed to acquire spectra.
   • If moves are large, click Send Moves and Retake Image button to offset the telescope and/or rotator and iterate to further refine the position.
   • If moves are small, click Send Moves Only button to send moves without starting another iteration.
   Note: if observing conditions are variable, it may not be possible to converge below the threshold limits.
In the case the Fine Align procedure does not converge, you can use the alternative Imaging Coarse Align procedure.

Acquire Spectra

1. Click GO BACK. On the Dashboard's gratings subpanel, click the GO BACK button to tilt the grating back to the science wavelength position for spectroscopy.
2. Select Spectral readout. On the Dashboard, change the CCD readout mode to Spectral.
3. Set exposure time. On the Dashboard, set the exposure time to the appropriate length (typically 900-1800 sec) and enter the desired number of exposures in the entry box to the right of the Expose button.
4. Click update CCD to set the exposure parameters.
5. Execute wffcs ; goi. Type this command into a polo xterm window. This will wait for the FCS to track and then will start a spectral exposure.
6. Verify exposure. Make sure that the exposure begins. It may take a couple of minutes for the FCS to lock.