Quick Reference

Contact your Support Astronomer [FN]

  1. Identify your Support Astronomer. If you do not know who your assigned SA is, you can find the name on the observing schedule posted in the Remote Ops I room in Waimea (or available online). Contact numbers for all members of the SA team are posted beside the white board.
  2. Arrange a meeting. Your support astronomer will meet you around 2:00pm HST in Remote Ops I unless a different arrangement is made in advance.
  3. Review your program. You should make sure to discuss the following points with your SA:

Determine your observing account

  1. Consult the on-line Keck I observing schedule. Find the listing for today's date (note that the dates are HST, not UT dates).
  2. The eighth column of the table will indicate the account you have been assigned. For example, if it reads LRIS(1), your account is lris1. Enter this account name (in lowercase) when logging into Keck computers. Your SA will supply you with the password for your account.

Login and Launch VNC

Regardless of whether you'll observe from Waimea or a mainland observing site, all of your LRIS software runs within VNC desktops. VNC servers for your run should be up and running five days prior to your run. Please follow the appropriate set of steps below to launch your VNC viewers on the primary and secondary workstations. [FN] your SA will help you with the first startup of the system. Please follow the instructions for your particular site (Waimea or one of our remote observing stations).

About your VNC desktops

You should see 4 VNC desktops come up labeled "control0", "control1", "control2", and "telstatus". They all have a blue background. This is unlike the previous (prior to mid-2019) setup which had 8 VNC desktops with a mix of tan and blue backgrounds.

Check instrument availability

You are not permitted to operate LRIS until the summit staff have completed their checkout procedure! Please follow these steps to determine when LRIS has been released for your use:
  1. Launch the Firefox browser from the desktop menu by selecting Firefox - LRIS Home Page.
  2. Click on the link labeled Instrument Ready? (available on the side menu on any LRIS webpage) to access the SIAS webpage.
  3. In the upper right of the SIAS webpage check the instrument status. If the displayed message reads LRIS NOT READY on a red background, then LRIS has not been released for your use. If it reads LRIS READY on a green background, then the instrument is ready for use. If it is past the nominal instrument release time (2:00pm weekdays or 3:00pm weekends), please contact your SA for assistance.
Note: you will not be able to take any dome calibrations until the telescope has been released; this generally occurs by 4:00pm HST.

Start primary host software

  1. Start the LRIS Software.
    Select LRIS Control Menu > Start All LRIS Control. from the vnc desktop menu. An xterm window will pop up with the following message: 
    	Welcome to the LRIS initialization script.  You should ALWAYS run this script 
	at the start of any observing nights of your run to undo any changes that the previous 
	observer made to LRIS and to re-initialize hardware ans software.
    The script is self-explanatory, but in case you want to know more, follow the link.

    When finished, the script will beep and print the message: 

    	Instrument initialization completed --- please proceed with observing
    and the xterm window will disappear.

  2. Verify windows.
    Check that the following windows appear:
    Left screen
    (control0 desktop)     		Center screen
    (control1 desktop)     		Right screen
    (control2 desktop)
    • XLRIS widget
    • CCD log window
    • Motor log window
    • Object.tcl window
    • PIG - Program Interface GUI
    • blue XPOSE gui
    • blue DS9 image display
    • instrument compass rose
    • ADC Status Gui
    • Eventsounds
    • red XPOSE gui
    • red DS9 image display
  3. Select sounds.
    The eventsounds GUI (found on your control1 desktop) allows you to choose which sounds to play when images are done exposing and reading out. Click on the available menus to select the sounds of your choice for your late-night entertainment.

Start secondary host software

Check your secondary host machine. If you are observing at a mainland site and your primary computer is equipped with four screens, then this single machine serves as both your primary and secondary host.
  1. FACSUM/XMET.
    If your team includes remote observers who cannot view FACSUM and XMET on the gorgeous wall monitors in the Waimea Remote Ops room, then launch them within VNC:
  2. Launch MAGIQ Guider Interface.

Verify instrument's setup

The following elements are loaded into LRIS upon request:

Verify ADC

Look at the ADC Status GUI in the control1 VNC.

Prepare Observing Log

You now have the choice of maintaining paper or electronic logs for your observing run.

Electronic logsheets

The Keck Observing Log Archive (KEOLA) maintains an on-line log of your run which you can access through the browser window to view or edit. This log is generated whether or not you choose to use it, and is only accessible from within the Keck network, not from outside, so if you are observing remotely you must launch a browser within VNC to access the electronic logs. For full instructions, please refer to the KEOLA webpage.

Paper logsheets

If you prefer physical logsheets for note-taking, now would be a good time to prepare them. You can preview and print out copies of logsheets from the computer. To assist in your logging, you may find it helpful to launch the obslog window which provides a summary of your LRIS exposures. From the LRIS background menu, select LRIS Utilities > Obslog loop to launch this window.

Optional: Take test exposures

Test exposures are taken to ensure that everything is fine with the instrument and the light path. You can skip this step if you will be acquiring afternoon calibrations (bias and dark frames, flatfield images, etc.) for your science program.

If you do not want to save the test images, turn off the write to disk option (only available on the blue channel): in the Xpose GUI, click on Disk... and select Disabled for the Disk Write option (left hand side). Do not forget to re-enable disk writing when you take your calibrations!

The steps below assume that you are familiar with the use of the XLRIS, XPOSE, and ds9 GUIs. If not, then please follow the links to read more the operation of these GUIs. Your SA will also be glad to provide you with training the use of these tools.

  1. Take test bias exposures.
    2. For both red and blue side, in the XPOSE GUI:
    1. Close the trapdoor.
    2. Set exposure time to 0.
    3. Click on the Start Dark button.
    4. Once the frames are written, inspect the frames.
    5. If you see something unusual, contact your SA.
  2. Take test illuminated exposures.
    3. Configure for imaging on both side. This can be done via a script: in the lrisserver window type take_test_flat and hit Enter.
Alternatively, you can configure the instrument and manually take the images:
Red-side settings Blue-side settings
  • Set grating = mirror
  • Set red filter = R
  • Set dichroic = 560
  • Set grism = clear
  • Set blue filter = G

MOS: Verify custom slitmasks

Observers using LRIS in Multi Object Spectroscopy (MOS) mode should take images of their masks and verify that they correspond to what was requested. Although errors are rare, it is possible for the wrong masks to be loaded, or for the correct masks to be loaded backwards into a slitmask holder; thus, your diligence is essential to ensure that the masks are correctly loaded. If an error is caught early enough in the afternoon, there is usually time to correct it. If you discover any problems with your masks, alert your SA immediately. Please note that you should repeat this procedure before each night of your run, even if you are using the same masks.

Automated Procedure

Follow these steps to verify your slitmasks slitmasks with the LRIS Slitmask Imaging Tool:
  1. From the desktop menu, select LRIS Utilities > Slitmask Imaging Tool to launch the LRIS Slitmask Imaging Tool (Linux)
  2. Use the check boxes on the GUI to indicate which masks to image.
  3. Click GO to acquire direct images of the masks.

Manual Procedure

Alternatively, if you prefer NOT to use our automatic GUI, you may manually cycle through the slitmasks. The following instructions for manually verifying slitmasks assume use of the blue side.
  1. Configure the lris blue side in imaging mode:
    • Close the trapdoor.
    • Set grism = clear.
    • Set filter = G.
    • Switch on the Argon lamp.
    • Insert the slitmask you wish to image.  
    • Set exposure time to 1 sec.
  2. Take one exposure.
  3. Verify slits: verify that all slits and alignment holes are in their expected positions and that all slits appear clean. If dirty slits are suspected, they can be removed and cleaned if summit personnel are alerted soon enough.
  4. Verify the masks Verify thedesign by comparing what is seen in ds9 or the SAT with the mask design. The following picture shows the relative orientation with respect to the plot available in the Mask Data Base.
  5. Repeat: repeat the preceding steps for your remaining slitmasks.

MOS: Identify Alignment Boxes

In this step, we define the positions of the alignment boxes and create coordinate files for use during the night.
  1. Launch SAT.
    Start the Slitmask Alignment Tool as follows:
  2. Identify boxes.
    Follow the Identify Boxes steps at: Identify Slitmask Alignment Procedure

Prepare the target list

  1. Create starlist.
    This can be accomplished in either of two ways:
  2. Transfer starlist.
  3. Verify starlist.
    To make sure that your starlist file is properly formatted, please do the following:

MOS/Longslit: Determine a Central Wavelength

If this is your first night or the gratings have been swapped, you will need to determine the central wavelength for spectroscopic observations. The wavelength range on the blue side is determined by the choice of grism, while the red gratings have adjustable tilt that allows modications of the eavelength range. Check the dispersive elements web page to learn more about the accesible wavelength ranges for each grating and grism.

Each grating can be inserted in any one of the four available grating ports. Since the ports have slightly different zeropoints, the central wavelength selected by means of the XLRIS GUI can be off the mark by a few hundred Ångstroms. Accordingly, using the grating angle settings from a previous run will probably not yield the same central wavelength, unless the grating of interest was installed in the same port each time. It is therefore recommended that you acquire some test arc lamp frames and check that the wavelength range is as desired. Furthermore, it is recommended to use a wavelength script to set the central wavelength.This script is run from the command line on a LRISserver xterm.

The arcplots tool can generate custom arc line plots for any combination of grating, dichroic, lamps, and central wavelength, and thus is useful for wavelength determination.

The following instructions assume use of the red side.

  1. Configure the red side in spectroscopic mode, as required by your science program
    • Select one of your slitmasks or the chosen longslit.
    • Select the grating you will be using for your science.
    • Select the filter you will be using for your science.
    • Specify your desired central wavelength.
    • Close the trapdoor.
    • Turn on the desired arc lamps. The Ar lamp in particular has a spectrum well-suited to wavelength calibration.
    • Set exposure time to 1 sec.
  2. Take an exposure in spectral mode with the red-side detector system.
  3. Make a row plot in ds9 (click and drag left mouse to create a vector plot) and check the peak counts. If needed, increase the exposure time and take another exposure to get sufficient signal.
  4. Compare a row plot from your image to the plot displayed by ARCPLOTS for the same instrument setup. Identify key features and estimate the central wavelength. If the wavelength coverage is not optimal, adjust the Wavelen or MSWavelen settings as required and take another exposure.
  5. Repeat the procedure for each slitmask/grating combination needed for your science program.

Optional: Create setup files

If your science program requires multiple instrument setups during the night, it is recommended to create setup files.

There are various ways to create setup files. We present here the two simplest ones:

  1. Instrument State files
    It is possible to save and restore snapshots of the LRIS status using the scripts save_state and restore_state. These scripts are run from the lrisserver window. For a complete description of the options see the save_state and restore_state scripts.

    Note:

    1. The script save_state generates ASCII files which can be easily edited.
    2. The snapshot may also include CCD keywords and other parameters, unlike the XLRIS scripts
    3. The restore_state script can generate error messages in case of failures. If it is run with the -verify flag then it will actually verify that the new setup has been applied to LRIS.
    4. Red CCD parameters ARE NOT included.
  2. XLRIS setup files
    This option has been discontinued.

Determine Instrument Focus

Both the red and the blue cameras need to be re-focused daily.

As the observer, you're responsible for determining the nominal focus of the red and blue cameras using the following procedures. Remember that if the cameras are not properly focussed, the telescope focus will be determined incorrectly!

The focusing process might be a little complicated due to the large number of different focal planes of LRIS, and the confusion between the instrument focus and the telescope focus. Due to the way it is designed, LRIS has three main instrument focuses:

  1. the imaging focus
  2. the longslit spectroscopy focus, and
  3. the MOS spectroscopy focus.
Each focus depends on the instrument configuration. The imaging focus depends critically on the filter. Both the longslit and the MOS focuses vary with grating/grism, central wavelength, and possibly the selected order-blocking filter. If your observations include a combination of imaging and spectroscopy and multiple configurations, the afternoon focusing procedure can be extremely time consuming, and needs to be started as soon as possible. On the other hand, there are two main shortcuts that allow for shorter focusing procedures:
  1. Once the imaging focus has been determined for one configuration, the focus for other filters can be obained using the focus table. The procedure is described in detail in the Imaging focus section below
  2. Once one of the two spectroscopy focus has been measured (either MOS or long-slit), the focus for the other mode can be obtained by using the focus table, provided the instrument configuration is exactly the same (wavelength, grism, grating, filters)
There are now three different methods for focusing the instrument:
  • Note 1: Large focus variations on both cameras have been observed. Thus, it is important to focus the instrument each night.
  • Note 2: We recommend that observers focus for every configuration and use the focus table as a backup. Also, please remember that the focus table only gives approximate values.
  • Note 3: The instrument is focused in the afternoon. Therefore, we assume that this value will be stable throughout the night. We find that the focus fluctuations during the night are about 30 steps in the blue and 0.01 in the red which are much less than 0.01arcsec in fwhm.

    Acquire Arcs and Flats

    Afternoon calibrations are required to determine wavelength calibration and flatfielding. In spectral mode, these data can be obained in several ways, as described below.

    Automated calibrations

    Acquire a spectral calibration sequence automatically with the Slitmask Calibration Tool, which you launch from the background menu via Background Menu > LRIS Utilities > Slitmask Calibration Tool.

    This tool is rather self-explanatory, and produces flats and arcs for all your slitmasks. If you run it in the morning, check the Do end-of-night shutdown box to complete the instrument shutdown procedure when datataking is completed. Also please inform the OA how long the calibrations will take so that they can comunicate the info to the daycrew. In any event, the observer should aim to have the calibrations completed by 8:30 HST.

    Note that you will need to select the appropriate exposure time for your flats. A table with the currently suggested exposure times can be found here .

    Manual arc calibrations

    If you prefer to take arcs manually, follow this procedure:
    1. Configure LRIS for spectroscopic observations.
    2. Close the trapdoor.
    3. Turn on the desired arclamps.
    4. Acquire spectra for each longslit or multislit setup.

    Manual flatfield calibrations

    If you prefer to take flats manually, or if you want to manually check the proper exposure level:
    1. Wait for the telescope to be released and in the dome flat position. If the telescope is released:
      • View the K1 Status on the SIAS Page. If the line is green, the telescope is released.
      • Telescope Elevation = 45° (see FACSUM).
      • Dome and Azimuth are 90° apart (see FACSUM).
      • If the telescope has not been released and it is after 4:00pm HST, please contact your SA to determine when the telescope will be available.
    2. Select K1 Telescope Status Menu -> Dome Lamp Control GUI and allow a few seconds for the widget to appear.
    3. Select ON and then set the power level 0 to put the lamps on high power.
    4. Configure LRIS as desired and take images.
    5. WARNING: Please remember to switch off the lamps when you are done by selecting Quit.
    Until the telescope has been released (which typically happens by 4:00 PM), it's not possible to take dome flats. While waiting, you can take bias and dark frames. Note that the dark current on the CCDs is quite low, so most observers do not bother with darks. Also, the LRIS bias is basically featureless, so bias frames are generally not necessary either. Remember that LRIS is not light tight. Useful dark calibrations can be taken only of the dome is completely dark. Check with your SA to determine whether this is the case.

    Coordinate with the OA

    Observing Assistants customarily arrive at the summit around 5:30pm in winter and 6:00pm in summer. Once they arrive, you can do one or more of the following:
    1. Greet the OA.
      Introduce yourself to the OA and alert them to any immediate needs that you will have. Tell them if you are taking calibrations and inform them about your calibration plans.
    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. 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.
    4. Inform the OA of your plans for the night
      It is always good practice to inform the OA of your science plans: depending on the LRIS modes you plan to use (longslit, MOS, imaging), the OA will make decisions on how and when is best to focus the telescope. The OA can also be asked about specific observing techniques you are interested into (e.g dithering, offset pointing, etc). Just before opening, your SA will also be available to help with these issues. Do not be shy and ask.

    Dinner

    If you are reading this, you're probably very tired and hungry. Moreover, the real work is still ahead of you. Now it is a good idea to go get dinner and all other sources of sustainment you may need during the night. In each remote ops room there is a folder labelled Restaurant Guide for you to consult. Please also note that Starbucks (across the road, in the Foodland food court) closes, mercilessly and irrevocably, at 9:00 pm. But it opens at 5:00am.