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.
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. Note: 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 displayed.
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:
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 seeing: 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.
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
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" window. % which peserver /home/lpss1/guest/apps/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 available) to break from xterm use Cntrl-] telnet> send brk * cancel * so
UI> N name GO Slews to Next target 'name', which is the name of your SOurce entry in your catalogue.
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.
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 image. 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.
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. xsize ysize Adam:> UNWINDOW selects full-chip readout. Alternatively use the CHIP command.