Science Operations

Data Flow

Images from the science chips first arrive in the /newdata directory, which is mounted on the observer workstations. From there the data are copied to a UTdate (YYYYMMDD) subdirectory of /Repository, which is also mounted on these workstations. /newdata is cleared daily at noon, while the UTdate directories in /Repository are stored for several months. After this time data are accessed through the LBTO Archive.

Both /newdata and /Repository are NFS-mounted and read-only. Therefore, quick analysis is most efficiently done in /scratch/.

Tech chip images are located in /lbt/data/logs/lbc/tec.

Examining your data real-time

There are several ways to examine your images as they arrive in /newdata:

  • The python script RB_Science looks for and displays, in two tiled frames in ds9, the Red and Blue science images as they arrive in /newdata.  If the script aborts with an error, or does not display the image, stop it by typing Ctrl-C in the launching xterm, and restart it.  Once the images are displayed, the IRAF task, imexam, can be used to measure image profiles, contours and statistics, among other things, for both frames.
  • In the IRAF LBTtools package there are the tasks: qdisp, qlook and mext to display a single image or a list of images. More instructions on using LBTtools follow in the next section.

LBTtools

LBTtools is an IRAF package which contains tasks useful to quick analysis of data taken at LBT. It should be available from all partner accounts.

Setting up LBTtools:

  • At the IRAF prompt, type epar LBTtools and you should see something like the list below:

    (version= LBTtools v0.90: Oct 2010)
    (observe= OKuhn) Observer ID
    (camera = RedLBC) Specify the camera
    (focstat= RFBG) If IRTC, which focal station?
    (archive= /Repository/20110326) Path to the archived images
    (utdate = 20110326) UT Date of the observations
    (CatDir = default) Source catalog directory
    (Telside= left) Telescope side for IIF cmds?
    (calib = ) Not used
    (motd = yes) Type the welcome banner?
    (mode = h)
    ($nargs = 0)
    Edit or enter the following lines accordingly:

    • enter the partner or observer name for observe,
    • LBC, BlueLBC or RedLBC for camera. Note that some tasks, e.g. allseeing and lbcrangebal can override this setting.
    • focstat is not used for LBC and can left unchanged
    • for archive, enter the full path to the raw images, usually /newdata for current images or /Repository/YYYYMMDD for images obtained one or more nights before
    • enter the date as YYYYMMDD for utdate, and
    • the CatDir and Telside are not used for LBC tasks and can remain unchanged.
    • the calib directory is not used, and can remain blank
    • Run the task to effect these changes by saving and exiting and typing LBTtools.
  • Next, change directory into one into which you can write. Creating a UT dated subdirectory under /scratch is recommended. (Note that the /scratch directories are local to each machine; obs2:/scratch/YYYYMMDD is not visible from obs3, for example. The tasks will run faster from /scratch.)
  • Type prepdir in this directory to create some directories which LBTtools tasks will use.

LBTtools tasks often used with LBC:

  • qdisp — display an image given the timestamp as an argument
  • In the Observe package you will find the following tasks:
    • lbcrangebal — corrects pointing and copointing (when using both LBCB and LBCR)
    • ptautoadjust — corrects pointing (when using only one LBC)
  • In the LBC package you will find the following tasks:
    • skyseeing — end of night image quality monitor
    • iqplot — plots FWHM, ellipticity, theta as a function of position in focal plane
    • rotcenter — for use by support staff to measure the rotator center
  • In the Sandbox package you will find the following tasks, which may be run outside of the LBTtools environment:
    • qlook — uses mscdisp to display a multiextension FITS file or the chip indicated by the parameter imext. Can read list input and wildcards to display a series of images, and prompts the user before displaying the next image.
    • mext — like qlook but does not prompt the user and displays only one chip or a single FITS file. With the imext=0 flag for a single FITS file, this is useful to display a “movie” of tech chip images