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 "Bright Long" tab of the SAT.
   • Click on "Acquire Image" to image the object.
   • Click on "Move to Center" to center the object on the slit.
   • Click on "Acquire Image" to check centering.
   • Iterate acquisition and centering until star is center on the box.
4. Start Spectroscopic Observations .

Nominal slit center is at 1042.83, 1051

Slitmask Alignment

This checklist describes the procedure for aligning a relatively bright object on a standard MOSFIRE Longslit using the Slitmask Alignment Tool (SAT). This process differs from the procedure for aligning a MOSFIRE slitmask with the SAT.

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

Re-focusing the telescope is recommended periodically during the night but is not required for each mask alignment. It is generally recommended to re-focus the telescope when the telescope elevation angle has changed by 30° or more.

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.

Note:

• 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
   • Click the Pre Config Filter button on the SAT Bright Long tab to set filter and grating to nb1061-imaging.
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

In this step, we center the star within the small imaging window centered on the longslit.

1. Confirm that MOSFIRE is configured for imaging:
   • A longslit alignment mask has been setup and executed on the CSU.
   • A default instrument configuration is set on the Options tab and will override the current configuration if the selections are not set to “current” (with the exception of the filter, which will be NB1061 regardless of what you select).
2. Click Acquire image button. The software will then:
   • Reconfigure the spectrograph as needed to image the mask (ideally, you did this already while slewing to the target to save time).
   • Acquire an image of the target.
   • Read, analyze, and display image.
   • Mark measured object position with red cross.
   • Mark slit center position with blue X.
3. Review object centroid
   • If the automatic fit was not correct, then click on the correct center. The software should re-mark the object centroids with a new red cross.
4. Send telescope moves
   • Click the Move to Center button to offset the telescope and center the slit on the object.
   • Return to Acquire Image step above and iterate until the star is centered on the slit.
   • Please note that if seeing is variable, it may not be possible to center within better than a few pixels.

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

• Load an image from the data directory using Actions -> Load Longslit Image.