ESO3.6-m/EFOSC2 Observing Procedures

Contents

  1. Prepare OBs and Instrument Setup
  2. Afternoon Calibrations
  3. Observing
  4. Quick-look Tools
  5. Data Backup and Report

1. Prepare OBs and Instrument Setup

  1. The day before your run fill out the EFOSC2 Set-Up Form here
  2. Get latest version of the P2PP program from this link.
  3. Examples of science and calibration OBs can be found in this tar file.
    Download the .tgz file, and open it with
    %> tar xvzf EFOSC2_OBs.tgz
  4. Run p2pp in your computer or in the w3p6dhs computer in the control room.
  5. Load OBs with File --> Import
  6. Use the "Duplicate" and "View" buttons to copy and edit OBs.
  7. Make OBs for the targets in the exposure time list. See the Observing section below.
  8. Check the object coordinates are right
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2. Afternoon Calibrations

  1. Darks:
    Use OB template EFOSC_img_cal_Darks.
    Set the following values:
    • Number of exposures: 10
    • Exposure time: 0
    • CCD windowing flag: F
    • CCD readout speed: normal
    • CCD X & Y binning: 2
  2. Dome flats:
    Use OB template EFOSC_spec_cal_Flats.
    Set 4 different templates, for Gr. #3 and #5, each with both slits #1.5 and slit #5.0
    Set the following values:
    • Number of exposures:
      • 15 for Gr. #3
      • 5 for Gr. #5
    • Requested intensity level: 40000
    • CCD windowing flag: F
    • CCD readout speed: normal
    • CCD X & Y binning: 2
    NOTE: We need 15 flats in blue because the response is very low at the blue end with Gr. #3.
  3. Arc lamps:
    Use OB template EFOSC_spec_cal_Arcs.
    Set 2 templates with slit#1.5, and Gr. #3 and Gr. #5.
    Set the following values:
    • He lamp exposure time:
      • 1.3 for Gr. #3
      • 0.5 for Gr. #5
    • Ar lamp exposure time:
      • 6.7 for Gr. #3
      • 0.1 for Gr. #5
    • CCD windowing flag: F
    • CCD readout speed: normal
    • CCD X & Y binning: 2
    Check that wavelength range is correct and that lines are in focus (2-3 pixels wide)
  4. There is no need for internal flats
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3. Observing

  1. SNe:
    Generally observe SNe with both Gr. #3 and Gr. #5, taking 3 exposures in each mode.
    Follow each series of 3 exposures by an arc lamp, obtained as described in point c above.
    Use a separate OB for each grism, including 3 templates in each case:
    • EFOSC_img_acq_MoveToSlit, with these values:
      • CCD readout speed: fast
      • Exposure time: 20
      • Filter:
        • V#641 for Gr. #3
        • R#642 for Gr. #5
      • X pixel coordinate: 1100
      • Rotator offset angle: -9999 --- (Paralactic angle)
      • Perform combined offset: T
      • Focus flag: T if you moved the telescope before this. Otherwise, F
      • Preset flag: T
      • CCD X & Y binning: 2
    • EFOSC_spec_obs_Spectrum, to get the spectra with:
      • CCD readout speed: normal
      • Number of exposures: 3
      • Observation type: OBJECT
      • CCD windowing flag: F
      • Filter: Free
      • CCD X & Y binning: 2
    • EFOSC_spec_cal_Arc, as described above.
      This gets an arc lamp at the position of the observation to avoid flexure errors.
  2. Flux Standards:
    Observe at least 2-3 flux standards during the night.
    Flux standars should be observed with slit#5.0 Use one OB for each star, including two templates:
    • EFOSC_img_acq_MoveToSlit, with these values:
      • CCD readout speed: fast
      • Exposure time: 2
      • Filter: V#641
      • X pixel coordinate: 1100
      • Rotator offset angle: -9999 --- (Paralactic angle)
      • Perform combined offset: T
      • Focus flag: T if you moved the telescope before this. Otherwise, F
      • Preset flag: T
      • CCD X & Y binning: 2
    • EFOSC_spec_obs_Spectrum, included twice, once for each grism, with:
      • CCD readout speed: normal
      • Number of exposures: 1
      • Observation type: OBJECT
      • CCD windowing flag: F
      • Filter: Free
      • Starplate: slit#5.0
      • CCD X & Y binning: 2
  3. Telluric Standards:
    Observe one telluric standard during the night, with high S/N.
    Telluric standards are observed much like SNe, the only difference is that 1 exposure per grism is taken.
    The narrow slit (slit#1.5) should be used, and an arc lamp is required after each exposure.
    So, two OB's per star should be created, the same way as for SNe.
    The exposure times in the target list are set so that the telluric standards are observed with high S/N ratios.
    Please raise exposure times if needed to obtain high S/N.
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4. Quick-look Tools

  1. You can look at the data in the offline computer.
  2. The easiest way to examine the images is using GASGANO and SKYCAT. To run them, just type the program names in any terminal.
  3. ESO has made available a quick-look tool for long-slit spectroscopy based on MIDAS. Everything it does is explained in this short manual.
  4. IRAF is also available with its standard packages.
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5. Data Backup and Report

  1. Fill out Backup Request Form
  2. During the night, write a report in a text file, including info about objects observed, exposure times, time spent, data quality (S/N, seeing), possible problems, sky conditions, and any other significant comment.
  3. Send the report to Gastón Folatelli at the end of the night.
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