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Zeroset encoders

           UI> ZEROSET     - hit <cr> to begin. Drive back through zenith in 
                             each axis until each pair of illuminated green 
                             arrow keys goes out. If only one pair
                             illuminate then press ACK to abort, and try
                             again, without moving the telescope. Repeat
                             also if Zeroset drops out immediately.

Dome shutters and mirror petals

Flat Fields

The easiest method would be to illuminate the slit with the Tungsten lamp in the integrating sphere attached to the Ellis A&G box. Tungsten flats should be used for the dispersion direction, and sky flats for correcting pixel-to-pixel variations in the spatial direction. For sky flats do the following:

           UI> IN BLANK        inputs catalogue of blanks fields, suitable
                                 for sky (twilight) flat-fields.

           UI> L              lists directory.

           UI> N BLANKn GO    marks next target as BLANKn, and slews to it.

           Adam:> GLA n       initiates a glance run of n secs.

                                   WINK n   n secs, image stored in Scratch,
                                            with no header packets, so used for
                                            quick peeks only.

                                   GLANCE n  n secs, image stored in Scratch,
                                             but with header packets. If 
                                             you decide to keep it use KEEP 
                                             which puts it into your directory,
                                             which prompts for a name.

                                   RUN n "title", creating a named file where 
                                             n is the exposure in seconds.

           Adam:> DIP 2 0 65000    changes display range of Lexidata to
           Adam:> DISP                0 to 65000 ADU's. The 2 specifies that
                                      all 16 bits of digitised data be 

If counts are satisfactory then the Glance file may be saved from scratch to a disk file using the KEEP command:

           Adam:> KEEP "title"


The SNAFU procedure is necessary to define the collimation and index errors, and incorporate these into the pointing model.
(During set-up the slit centre should be marked on the TV, using the following procedure: illuminate the narrow star dekker by the tungsten lamp, with the SLIT mirror in the beam. You must type OPEN at the Adam terminal first to open the above slit shutter, otherwise you wo'nt see anything. Mark the slit centre on the TV then revert to longslit dekker afterwards.)

           UI> SNAFU          Use the green console buttons to centre star on
                              slit centre mark on TV (see above).
           Press ACK          to acknowledge (lower right of control desk).

This is the first SNAFU, using the Comparison mirror. In case there is any displacement between the Comp and slit mirrors, repeat with the slit-mirror, which is more important.

           Adam:> COMP OUT    to move the comp mirror out of the beam

           Adam:> SLIT IN     to move the slit-view mirror into the beam

           UI> SNAFU          Use the green console buttons to centre star
                              on slit centre. 

           Press ACK          to acknowledge (lower right of control desk)


The slit jaws are reflective to aid target acquisition and field identification. Unfortunately the optimum focus must be determined visually from the TV - using a small number of on-target integrations to sample the seeing, is probably easier than using the direct TV. The best procedure is as follows:

Enter Sources / Create Catalogue (at User Interface)

           Rules: - only 80 char records allowed.
                  - filename must consist of 8 alphanum chars or less,
                       starting with a letter and have the extension .CAT.
                  - no more than 500 objects per file. 

           UI> DEL/ALL        to delete all entries in UI directory.

           UI> SO name  R hh mm ss.s  D dd mm ss.s  EQ B1950 (or J2000 etc.)

           Repeat above for each target. At end:

           UI> SAVE MY.CAT    saves catalogue with name MY.

           UI> IN MY          inputs catalogue on subsequent nights.

           UI> L              lists catalogue just INputted.

           UI> N name GO      Slews to Next target 'name'.

           Standard catalogues, loaded into dictionary using UI> IN name :

              PTGRID          pointing grid, with  4 subsets for measuring

                 SEE0006      0 hr < RA < 6 hr
                 SEE0612      6 hr < RA < 12 hr
                 SEE1218      12 hr < RA < 18 hr
                 SEE1824      18 hr < RA < 24 hr

              SPECPHOT        spectrophotometric flux standards.

Network transfer from PE to Sparcstation

By the stage you may well have a few runs under your belt, and even if you have'nt, now would be a good time to start the network software to allow automatic file transfer between the Perkin-Elmer and the Sparcstation (lpss6), and start AUTOFITS if you have'nt already done so. The following is NOT intended to replace Gary Mitchells' more comprehensive notes, which should be beside the Sparcstation, only to be a concise summary. If you experience any problems (or even if you don't!), please read Gary's notes before taking further action.
In the following summary, assume I signed into Adam account 2 (e.g. si pjr,2,2). The necessary dialogue is then:

           Pull up a command tool window, which is referred to as the "Server"

           % which peserver

           % obsdata              (lists obsdata partitions)
           % cd /obsdata/lpss6n   (n=a,b,c,d from preceeding command) 
           % mkdir yymmdd
           % cd yymmdd
           % peserver nnnn    (port number used later)

             to break from server use Cntrl-C

           Next pull up an xterm window, which is referred to as the
           "Xterm terminal"

           % telnet jktpe
           * si phil,2,2      (different name but same account, used in Adam)

           % peclient
                > lpss6
                > CCD
                > pjr         (same initials as used in Adam)
                portnumber> nnnn  (as used in Server window)
                first file> 1
                last file > 100   (network grabs each file as it becomes

             to break from xterm use  Cntrl-]
                                      telnet> send brk
                                      * cancel
                                      * so


Target Acquisition

           UI> N name GO        Slews to Next target 'name', which is the
                                   name of your SOurce entry in your


Before starting an exposure it is best to window the chip in the spatial direction:

           Adam:> WINDOW        and reply to prompts, which expect lexidata
                                co-ordinates, so use PHOT to get these first. 
                                To revert to full chip readout enter:

                                   Adam:> UNWINDOW

           Adam:> RUN t "title"  to do a t seconds integration, which will
                                   be called "title".

                                Alternatively to do multiple exposures of
                                   t secs each enter:

                                   Adam:> MULTRUN n t "name"

                                   Note that when using MULTRUN, the images
                                   are NOT displayed automatically after
                                   each exposure. To abort from MULTRUN use
                                   the command KILLMULTRUN. 

            While the RUN is in progress it is possible to monitor or
            change its status by using the following:
               Adam:> RUNSTAT      for elapsed time.

               Adam:> PAUSE        to pause exposure.

               Adam:> CONTINUE     to continue exposure after a PAUSE.

               Adam:> ABORT        to abandon observation - no file produced.

               Adam:> STOP         to force read-out at that time.

               Adam:> TIME         to change exposure time. 
           Other useful commands are:

               Adam:> DISP Rn      displays run number n from disk.

           If the RA button sticks, switch to INC and type:

               UI> HA/I 0          so that increment is zero. Then move 
                                      stars by either stopping telescope or
                                      with the REV button.

Displaying Big CCD images

Since the Lexidata display has only 640 x 512 pixels, attempts to display large CCD images using DISP causes only the central part of the image to be displayed. One rather cumbersome way to display other areas of the image is to set the Lexidata variables LXXC and LXYC explicitly, and then resetting them to their default values at the end, e.g.

               Adam:> LXXC=320
               Adam:> LXYC=256

A neater but more time consuming alternative is to compress or SQUISH the image by a factor of 2 or 3, and either display this 'squished' image using DISPSQ, or the more versatile BIGDISP, e.g.

               Adam:> SQUISH Rn       prompts for x and y binning factors
                                      (2 will barely fit an EEV image on the
                                      Lexidata, 3 will do it comfortably).
                                      This takes about 2-3 minutes.

               Adam:> DISPSQ Rn       will display the squished image on the
                                      Lexidata. A flexible alternative is
                                      to use:

               Adam:> BIGDISP Rn      will display the squished image and
                                      run PHOT. Position the cursor on the 
                                      point you would like to have as the
                                      centre of the full-scale image. Press
                                      the blue READ button twice, with a
                                      small time interval in between. Press
                                      the EXIT button which will display
                                      the selected area of the full-scale
                                      You then have the option of exitting
                                      the procedure or displaying the
                                      squished image again and choosing
                                      another point as the centre of the
                                      full-scale display.

BIGDISP is very versatile, and avoids having to change the Lexidata display variables LXXC and LXYC, although you do have to squish the image first, which introduces an appreciable time overhead.

Readout modes

               Adam:> SETQUICK        turns on the fast readout mode, with
                                      higher noise.

               Adam:> UNSETQUICK      turns off fast readout mode. This is
                                      the system default on start-up.

               Adam:> BIN             used to enable on-chip binning. Two
                                      parameters are prompted for, the
                                      x and y bin size: binning can take place
                                      up to a maximum of 4 x 4 pixels,
                                      including combinations such as 2 x 1,
                                      3 x 2 etc. BIN cannot be used with
                                      parameters x=y=1, or in conjunction
                                      with the WINDOW command.

               Adam:> UNBIN           disables on-chip binning. This is the
                                      system default on start-up. Alternatively
                                      use the CHIP command.

               Adam:> WINDOW          defines a window for readout. There are
                                      four parameters which are prompted for:
                                         xstart  | window origin relative to
                                         ystart  | top RHS of Lexidata display.

               Adam:> UNWINDOW        selects full-chip readout. Alternatively
                                      use the CHIP command.


Humidity & Wind

Copying Data

next up previous contents
Next: MORNING ACTIVITIES Up: Observers Guide to the Previous: AFTERNOON ACTIVITIES

Peter M. Sorensen
Fri May 16 18:01:04 BST 1997