Quick Review

1. Focus the telescope using MIRA: if needed
2. Slew to target and while slewing
• Configure MOSFIRE to image the alignment slitmask
3. Fine Alignment:
   • Click on "Start fine alignment" to image the mask
   • Repeat Fine Alignment if necessary.
4. Start Spectroscopic Observations .

Slitmask Alignment

To launch the SAT:

• Navigate to an “analysis” VNC desktop (blue background)
• From the window manager pull-down menu select MOSFIRE Utilities -> Slitmask Alignment Tool

Focus telescope

To complete the focus:

1. Highlight the target in the MAGIQ target list using the middle mouse button, and ask the OA to slew to the new highlighted target.
2. Ask to OA to run MIRA in the neighborhood of your target.

• If you plan to observe the field for two hours (or more), you may ask the OA to run MIRA one hour west of your target field.
• MIRA is always run using the J band filter.

Slew to Target

1. While slewing
• Configure the spectrograph to image the longslit alignment mask.
  • Configure the CSU with the alignment longslit
  • Set filter and grating J-imaging (default)
2. When the OA tells you that your target is on MOSFIRE, check the following information on FACSUM to verify that your position is correct:
   • Target name and coordinates
   • Position angle (skypa)
   • Pointing origin (should be SLIT)

Fine Alignment

1. Confirm that MOSFIRE is configured for imaging:
   • Longslit alignment mask selected.
   • A Default instrument configuration is set on the Options tab and will override the current configuration if the selections are not set to "current."
2. Click Start Fine Alignment button. The software will then:
   • Reconfigure the spectrograph as needed to image the mask (saves time if done while slewing to the target).
   • Acquire an image of the sky a few arcseconds away.
   • Acquire an image of the target.
   • Subtracts the sky image from the target image
   • Read and analyze 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.
3. Review Object and Box fits, calculated offsets, and move recommendations. For the 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 box on the Fit Residuals plot on the right.

   XYFIT codes

   Graphic	Description
   white solid line	star profile (sky subtracted)
   white dotted vertical line	star center
   red solid vertical line	Predicted star position
   green box	shows centering of the fitted box
   yellow dashed line	box profile (object +sky)

4. If you want to change a move recommendation, select the Y or N button next to the offset. Note: rotational moves are not calculated for single stars.
5. Send the Moves
   • Click Send Moves and Retake Image if moves are large and a second image is needed to further fine tune the position.
   • OR click Send Moves Only if moves are small.
   • If conditions are variable, it may not be possible to converge below the threshold limits.
6. In case Fine Align fails to find the star, we can perform alignment manually
   • The workaround is to manually move the target to the slit center with the mov command.
   • On a vm-mosfire or mosfireserver terminal, type mov x1 y1 x2 y2.
   • x1 and y1 are the star pixel coordinates obtained from ds9.
   • x2 and y2 are the slitcenter pixel coordinates.
   • The most recent slit center coordinates are x2=1044.2 and y2=1051.2 as of February 16, 2022. It can also be measured from ds9.

Spectroscopy

1. Reconfigure the instrument for spectroscopy:
   • Configure the CSU for spectroscopy.
   • Set obsmode (grating and filter).
   • Set the exposure parameters.
2. Expose...phew!

Tips and Tricks