Workshop Tutorial - Planning CHARA Observations


  1. Pick a target - estimate the angular diameter (or binary separation, disk size, etc). 

    JMMC Stellar Diameters Catalogue available through VizieR.

    Color relations, look up tables etc.

  2. Run JMMC planning software.  The software can be run online using the JMMC servers or you can sign up for a JMMC account and download the java jar file directly (see Installation Help).  Today we will use the online version.

  3. Select calibrators using SearchCal.

    Click on the "Download Application" link.

    Open with IcedTea Web Start.

    Click Proceed... Allow... Create Desktop Shortcut...

    ---- Wait until SearchCal GUI opens. ----

  4. Enter Target into SearchCal.

    Select wavelength filter band and maximum baseline.

    Select magnitude search range.

    Click on the "Get Calibrators" button.

    After search results appear, take off flags for:
    "Reject Spectral Types (and unknowns)"
    "Reject Luminosity Classes (and unknowns)"

    Click on the HD number of possible calibrators to bring up the SIMBAD page and review references.

  5. Start the planning software ASPRO2.

    Click on the "Download Application" link.

    Open with IcedTea Web Start

    Click Proceed... Allow... Create Desktop Shortcut...

    ---- Wait for ASPRO2 GUI to open. ----

  6. Enter target and calibrators into "Targets" box in ASPRO2.

    Select calibrator and click the "Editor" button.

    Click the "Flag Calibrator" button.

    To associate a calibrator with a particular science target, click on the calibrator, drag and drop onto target name.

  7. Select Interferometer: CHARA

    Select Instrument: CLASSIC, CLIMB, MIRC, JOUFLU, PAVO, VEGA.

    Select Baseline Configuration (e.g., S2-E2-W2)

    The POPs set the fixed delay and determine when the target can be observed on sky.  Selecting "Auto" will select the optimal POPs.  Changing the POPs will change the timing of the delay window.

  8. The "Map" tab gives a layout and the baseline lengths for a selected configuration.

  9. Click on the "Observability" tab to see when the targets are available on sky.  Change the POPs (by selecting options from pull down menu or setting by hand) to see how the POPs affect the timing.

  10. Click on the tab for "UV Coverage."  This gives the UV coverage of the telescope baselines projected on to the plane of the sky.

  11. Add a target model by clicking on the target name in the "Targets" box.

    Click on the "Editor" button.

    Click on the "Models" tab.

    Select the model type (disk, point source, ring, etc).  Then click the "Add" button.

    Enter the diameter value into the model parameter box.

    Hit "OK".

    Now the "UV Coverage" will show the two-dimensional Fourier Transform of the model overplotted with the UV sampling.  Change the telescopes to see how the UV coverage changes.

  12. The "OIFITS Viewer" tab plots the simulated squared visibility data (Vis2data) and closure phases (T3Phi) for the selected model, instrument, and telescope configuration.

    At the bottom of the page, select color by "baseline or triplet".

    Change the "Instrument" to MIRC_6T to see all possibilities of available baselines.  Look at both the UV Coverage and OIFITS Viewer.

  13. Use the Target "Editor" button to add a second model component (e.g. point source binary companion at 5 mas separation, ring, elongated disk, etc). 

    See the effects on the Fourier Transform (UV Coverage tab) and the "OIFITS" tab.