The following afternoon routine is recommended to prepare for the night's observing.

Time to complete: About 1 hour + 8 minutes per mask


Check Account

  1. Consult the on-line Keck observing schedule. Note that the dates are HST, not UT dates.
  2. The third column of the table will indicate the account you have been assigned. For example, if it reads deimos7, use this account name (in lowercase) when logging in to Keck computers.

Start Up VNC

Whether observing from Waimea, from an official remote observing site or from home, DEIMOS observers should run all instrument software within VNC desktops. Generally, VNC servers for your run should be up and running when you arrive to observe. Please follow the appropriate set of steps below to launch your VNC viewers.

Remote Startup Procedure from home

The procedure for launching VNC desktops from home requires previous installation of the Keck remote observing software. Once the software has been installed:

  1. Open a terminal on your local computer.
  2. Navigate to the directory where the remote observing software was installed.
  3. Launch VNCs with the following command:
    ./start_keck_viewers deimosN

Remote Startup Procedure from Official Remote Sites

The procedure for launching VNC desktops from remote sites varies from site to site, but generally follows this procedure:

  1. Log in. Log in to primary and (if applicable) secondary machines using account and password provided by the site manager.
  2. Get firewall access. If necessary, follow authentication procedure for access through Keck firewall.
  3. Launch VNCs. Execute the appropriate script to bring up VNC desktops. At sites with a single 4-headed machine execute the command
    kvncall deimos deimosN
    where N is the number of your DEIMOS observing account. At sites with separate primary and secondary machines, execute this command on the primary machine:
    kvncinst deimos deimosN
    and this command on the secondary machine:
    kvnctel deimos deimosN

Waimea Startup Procedure

  1. Log in to primary seat.
    1. User: user
    2. Password: See your Staff Astronomer
  2. Launch primary VNC desktops.
    1. Open a terminal
    2. Type: deimos7 (assuming that your assigned account for the night is deimos7.)

Check Instrument Status

  1. Start Firefox. (This can be started on any of the VNCs, but due to the final arrangement of the DEIMOS GUIs, it is convenient to start Firefox on the telstatus VNC.
  2. Read the DEIMOS News.
  3. Check instrument availability.

Prepare Observing Log

Electronic logsheets

Paper logsheets

  1. Select your preferred logsheet format on the DEIMOS logsheets webpage
  2. Print logsheets to the nearest available printer

To assist in your logging, you may find it helpful to launch the obslog window which provides a summary of your DEIMOS exposures. From the DEIMOS workspace menu, select DEIMOS Utilities → Obslog Loop to launch this window.

Start up DEIMOS

  1. Start up the DEIMOS software.
  2. Verify windows.
    Check that the following windows appear:
    Window Function
    Control0 desktop
    DEIMOS instrument control GUI Main control interface with the instrument
    fcstrack terminal (yellow fonts) Transcript of the Flexure Compensation System (FCS) control software (fcstrack)
    watch_fcstrack iconified terminal Restart automatically the fcstrack script if it dies
    watch_lickserv2 iconified terminal Restart automatically the CCD data taking software (lickserv2) if it dies
    watch2_ccd iconified terminal Restart automatically keyword monitoring software (watch_ccd) if it dies
    Control1 desktop
    Ginga display GUI Display DEIMOS science images in real time
    Deimos eventsounds GUI Control of instrument sounds
    Compas Rose (i) Represent the DEIMOS detector orientation
    Control2 desktop
    Slitmask Alignment Tool (SAT) GUI Used for MOS slitmask coarse and fine alignment
    SAT IDL terminal (blue fonts) IDL process running the SAT
    telstatus desktop
    Facility Summary (FACSUM) GUI Show overall telescope status
    MET GUI Show information from the Keck weather station
    MAGIQ Observer UI Visualize and manage target list during observations
    Program Identification GUI (PIG) Handles program ID, observer list and output data directory

In addition to bringing up the GUIs and control terminals, the DEIMOS startup script also creates the directory structure adequate for the night.

Select your program on the PIG

Click on the radio button next to your program code on the Program Identification GUI (PIG). This will automatically set the following fields:

If you would like to update the observers list, simply edit the corresponding field on the PIG and press the Set button.

IMPORTANT NOTE for ToO triggers and DEIMOS/DEIMOS split nights: If this is a DEIMOS/DEIMOS split night or there is a ToO trigger, make sure to select the correct program on the PIG before taking data. This will ensure that the images are saved in the correct data directory, and that the correct ownership is assigned to the data in the Keck Observatory Archive (KOA).

Verify configurable elements

  1. Verify slitmasks.
    On the Mechanism control area of the DEIMOS instrument control GUI, click in the Slitmask selection button. Read through the list of available slitmasks on the pull down and ensure that all of the slitmasks you will need tonight are listed. If not, get help.
  2. Verify gratings.
    On the Mechanism control area of the DEIMOS instrument control GUI, click on the Grating selection button. Check the available gratings on the pull down and ensure that all of the gratings you will need tonight are listed. If not, get help.
  3. Verify filters.
    On Mechanism control area of the DEIMOS intrument control GUI, click on the Filter selection button. Read through the list of available filters on the pull down and ensure that all of the filters you will need tonight are listed. If not, get help.

Select sounds

  1. Select sounds.
    The DEIMOS eventsounds utility will make user-selectable noises when: Click on the available menus to select the sounds of your choice for your late-night entertainment.
  2. Play samples.
    You can play a sample of the currently-selected sound by clicking the right mouse button on the label for the sound. If you do not hear the sound immediately, verify that your computer sounds are not muted. If you are using a computer with external speakers, make sure the speakers are powered on and that volume is turned up.

Reset stages

At the beginning of each afternoon, you should reset all DEIMOS stages to reasonable positions.

  1. Click on the Details... button on the Init/Stow area of the DEIMOS control GUI to open the DEIMOS initialization control GUI. Note that all the buttons on the intialization control GUI are disabled (grayed out) by default.
  2. On the initialization control GUI:
  3. Close the intialization control GUI by clicking on the Close button.

Take a test bias exposure

  1. Close hatch.
    If the DEIMOS instrument control GUI indicates that the hatch is open, then close it by selecting the closed option on the jatch mechanism control, and hit Apply. The hatch stage current value should change to closed once the stage has finished moving.
  2. Turn off lamps.
    If the Internal lamp control GUI indicates that any lamps are on, click on the Details... button on the Internal Lamps box, and then hit the All off button.
  3. Set exposure parameters.
    1. Set the following values on the Detector contol panel of the DEIMOS instrument control GUI:
      • Object:bias
      • Readout mode:Spectral
      • Amp mode:SINGLE:B
      • Obs type:Bias
      • Integration (s)0
    2. You can either Apply one change at a time, or Apply all (reccommended). changes. If you are unhappy with any of the new settings, you can Reset all before hitting Apply all.
  4. Start bias exposure.
    Click on the Expose button to start the exposure.
  5. Verify exposure sequence.
    After you start the exposure, the brown exposure progess bar to the right of the Progress: field will start changing in size. The Status: field will start being populated with the following values:
  6. Wait for readout.
    In about 75 seconds, the image should read out and display on the Ginga display GUI.

Inspect the bias frame

Use the Ginga display GUI to make a vector cut across your image, graphing pixel values as a function of position.

  1. Select the Raw channel and click the Operations button (below the main display area) and select Analysis → Cuts.
  2. Right-click at the point on the displayed image where you would like to start the projection cut.
  3. Release the mouse button once you are happy with the selected region.
  4. Inspect the Cuts plot on the Dialogs tab (upper right area of the GUI.)

The nominal bias frame should have about 1000 counts on average, and a peak-to-peak variation of less than 10 counts. However, not all CCDs on the DEIMOS mosaic show such values. Please, check the latest news on the DEIMOS CCD mosaic status, or ask your SA in case of doubt when assessing the quality of a bias frame.

Determine instrument focus

The DEIMOS internal focus can change significantly on a daily basis. Hence, it is advisable to refocus the spectrograph each afternoon. Since the offsets between various filters appear to be stable over time, the standard procedure is to focus the instrument in direct imaging mode using the R filter and illumination with internal lamps. Once the focus in this fiducial filter is measured and set, the instrument's automated filter focus discipline software will adjust the internal focus as needed to account for the changes in the filter. Follow these steps:

Since January 2020, we have a Python-based script to create the focus map which is faster than the old IDL script. Please, follow this link for a comparison between the old (IDL-based) and the new focus analysis script.

The VNC pulldown menu has 3 options to acquire the focus images and to determine the best focus value:

Run/Analyze focusloop (R+internal)

This is the recommended option, because it automatically launches the analysis script, once the focus images have been acquired. Please, once you have selected the option Run/Analyze focusloop (R+internal) on the pulldown menu, take your time to read the next two sections to understand what the focus data taking and analysis scripts do, how to exit from each script once they are completed, and how and when to input the optimal focus value on the DEIMOS control GUI.

Run focusloop (R+internal)

This option launches the script that acquires the internal focus images.

  1. Ensure that the DEIMOS rotator is not halted. Check that the Rotator mode on the system overview of the DEIMOS instrument control GUI is Pos. If the rotator mode is not Pos, then contact you SA for assistance.
  2. On the VNC background menu, select DEIMOS Utilities → Run focusloop (R+internal). A wait_wrapper terminal will pop up to run the focus sequence. If DEIMOS is not at the nominal rotator angle of -30deg, the following message will apear on the terminal:
     [do_focusloop] WARNING! The DEIMOS rotator is NOT at the
    	nominal rotator angle preferred for focusing (-30). If you
    	focus here, you may not get an accurate focus.  Should I
    	rotate DEIMOS to the proper position? (y/n) [y]: setting
    	rotatval = -30.00 (wait)
    As soon as DEIMOS is released, it will be safe to excute the rotation. In that case, you can answer y and hit Enter. The focusloop script will configure the spectrograph appropriately for R-band dome images and acquire a sequence of 7 focus images every 1000 focus units from -5000 to -11000.
  3. The focus loop script takes about 10 min to complete, so this can be a good time to work on your target list and upload it on the SAT.
  4. Once the focus loop sequence is completed, the instrument will be returned to its previous configuration, and the following message will appear on the wait_wrapper terminal:
    Press <Enter> to exit...
    Please, press enter to close the terminal.

Analyze focusloop

Run the analysis script once all the images in the focus sequence have been taken:

  1. From the DEIMOS background menu, select the item
    DEIMOS Utilities → Analyze focusloop
    A new wait_wrapper terminal will pop up to run the focus analysis script, which will display a PNG plot containing the focus map.
  2. Inspect the plot to verify that the overall morphology of the contours is similar to that seen in this sample plot.
  3. If the plot looks good, adopt the last value shown on the page or in the xterm output (labeled Array focus) as the nominal focus value. If it looks bad (see example of a buckled mask resulting in a poor focus like this), then notify your Staff Astronomer.
  4. On the DEIMOS instrument control GUI, enter the nominal focus value in the Focus box. IMPORTANT NOTE: Please, wait until the focusloop script has finished putting all the optical elements back to their original configuration. Once the focusloop terminal shows the message Press <Enter> to exit..., then you can enter the focus value on the Focus box. Note, that the focus stage only takes negative focus values.
  5. Press Enter to close the focus analysis wait_wrapper terminal.
The focus analylis plot and log are saved on the data directory. To reopen the analysis plot, on a terminal:
    eog direct_R_internal_2021-04-10.png &

Select grating, central wavelenght and filter

The method to select the grating will depend on the current rotator angle, which is displayed on the system overview area of the DEIMOS control GUI:

When selecting both, grating and central wavelength, the grating must be selected first, and the central wavelength must be selected only once the grating has already been clamped in position. This is required because the DEIMOS control GUI remembers which was the last wavelength that was selected for a given grating.

Select the adequate blocking filter for your grating setup using the DEIMOS instrument control GUI.

Check slitmasks

If you will be using custom slitmasks, you will want to confirm that the slitmask alignment software can properly locate the alignment boxes on your masks. Furthermore, taking mask images can be very useful for early detection possible problems with the slitmask selection mechanism.

The procedure to take the mask images and identify the alignment boxes is as follows:

  1. Acquire mask images. Obtain direct images of all of your slitmasks so that you can verify them:
  2. If it is not up yet, launch the Slitmask Alignment Tool (SAT). On any of your analysis VNC desktops (with blue background rather than tan), launch the Slitmask Alignment Tool from the background menu via DEIMOS Utilities → Slitmask Alignment Tool
  3. Select ID Boxes. The SAT window has various tabs available; please select the one labeled ID Boxes.
  4. Verify box locations. Use the SAT to confirm that the software can locate all of your alignment boxes:

Perform FCS calibrations

Complete the FCS Setup Checklist.

The flexure compensation system must be set up for each combination of grating and central wavelength that you will be using. Follow the checklist above to calibrate FCS. Different slitmasks may use the same FCS setup, however.

If you intend to use a grating set to more than one central wavelength, it is advisable to change the wavelength and confirm the FCS continues to track at both positions.

If you intend to use two different gratings, it is advisable to switch between the gratings to ensure FCS will continue to track following the moves.

Acquire arcs and flats

Acquiring arcs and flats should not be attempted until FCS is tracking using your science instrument configuration.

Automated method

To acquire arcs and flats automatically (preferred method) use the Slitmask Calibration Tool (Widget):

  1. DEIMOS Utilities -→ Slitmask Calibration Tool from the background menu to launch the gui.
  2. Click the checkbox next to the desired masks
  3. Confirm number of exposures and exposure times. Note that exposure times are set for 1 arcsec slits.
  4. Click GO to initiate the sequence of exposures.
For more information please see the Slitmask Calibration Tool (Widget)

Manual method

To acquire arcs and flats manually:

  1. Close the DEIMOS hatch to block dome light.
  2. Set the grating, central wavelength, filter, and dewar focus appropriately.
  3. Start FCS tracking (if desired) and wait for it to lock.
  4. If needed, take a test 1 second Qz internal flat (use the goibuf command) and determine the appropriate exposure time for your flats (goal is about 30,000 DN maximum).
  5. Launch the widget from the DEIMOS background menu via DEIMOS Utilities → Slitmask Calibration Tool.
  6. Select the masks to be calibrated using the current grating/wavelength/filter combination, the number of arcs and flats to acquire, the exposure times to use, and the arcs lamps to use.
  7. Click GO to begin data acquisition.
The normal set of 1 NeArKrXe arc and 3 internal flats will take about 8 minutes per mask to complete. Selecting the Cd or Zn lamps will require additional time.

Create and verify target list

You will need to create a “starlist” file listing your target names and coordinates. You can do this in either of two ways:

Automated starlist

Create a starlist based on the output files from DSIMULATOR:

  1. Download the file deimos_startlist.tar
  2. Extract the Python script:
    tar -xvf deimos_starlist.tar
  3. Run the script using Python 3:
    python *.out
    where "*.out" are the DSIMULATOR output files
  4. The resultant file is called starlist_YYYMMDD.dat
  5. Upload your resultant list to Keck using the Keck observer page as follows: Once uploaded through the web interface, your starfile can be found in the directory /kroot/starlists/web/username, where username generally includes your first initial and last name.

Hand-crafted starlist

Use a text editor to create and format your starlist as described here. If you have done this on your laptop, you can then upload the starlist file via our web interface:

Once uploaded through the web interface, your starfile can be found in the directory /kroot/starlists/web/username, where username generally includes your first initial and last name.

Load starlist in SAT

Load the starlist in the Slit Mask Alignment Tool. In the SAT GUI: Guider Coarse Align → Load Starlist. Navigate through the file browser until you find your starlist.

Load the DSS images for your coarse alignment. Pre-loading the DSS images in before sunset can save a bit of time during the coarse alignment. In the SAT GUI: Guider Coarse Align → Retrieve all Guider Images.

Optional: Generate guider finder charts

You can generate finder charts for the guider images and also generate the target list using the DEIMOS guider DSS tool, which you can run on your own Linux or Mac computer. Please, click on the Keck Observatory Github repository and follow the installation instructions shown on the Git page. Once you have installed the sofware:

  1. Create a directory in your local machine with your .out files from dsimulator (e.g. masks.)
  2. Run the software as follows:
    	cd masks
    	python [path_to_DeimosGuider]/deimos_guider_dss *.out
  3. Wait a few minutes for the software to create the finder charts and the target list. When completed, the software will respond with:
    	Point your browser to → file:///[path_to_your_dsim_out_files]/guider_images.html
  4. Use your browser to open this URL, which serves as an index to your finder charts and to the starlist file.
  5. Important sanity check: Verify that the finder chart shows stars in the locations of the markers where guide stars are expected. If not, then the mask may have an astrometry problem!
  6. Copy the starlist file into your directory in /kroot/starlists if you have not done it yet.

Coordinate with the OA

Observing Assistants customarily arrive at the summit (or HQ, if remote controlling) around 5:30pm. Once they arrive, you can do the following:

  1. Greet the OA. Introduce yourself to the OA and alert them to any immediate needs that you will have, such as wanting to take dome flats if your program requires direct imaging data.
  2. Wait for the OA to get settled. Setting up computers and bringing up all of the telescope control systems requires some time, and things go wrong much more often than we would prefer. Be patient while the OA prepares the telescope for operation.
  3. Take dome flats if needed. When the OA gives you permission to proceed, begin taking dome flats.
  4. Inform the OA about your starlist. Now would be a good time to let the OA know where your starlist is, so they can verify that they have access to it.

Get dinner

You're tired and hungry and there's a long night ahead. If you happen to be observing from Waimea, better get out the folder labeled Restaurant Dining Guide and select one of our fine local eateries to provide you with sustenance.

Proceed with evening setup

Sunset is getting close; continue with the procedures listed on the Evening Startup Checklist.