This is intended as a brief ``check-list" of observing with the SITe 2048x2048 CCD at the Hall 42-inch. More detailed information can be found at:

• CCD characteristics (table)
• Ted Dunham's memo on the SITe
• Documentation on the telescope control system MOVE (Larry Wasserman)
• List of CCD commands

Opening Up

Upstairs:

• Fill the dewar. Normal operating temperature is -133 degrees C; the dewar typically holds 18-22 hours.
• Open the dome (button on west side of dome).
• Open the mirror cover (hand crank on W side of telescope).
• Open the instrument shutter (top of guider).
• Turn on the main power on the console.

Control room:

• Turn on the RCA and Sony monitors.
• Log onto MOVE and follow the instructions to bring the system up.
• Reboot the CCD computers:
  • In the computer room turn off the two PCs on the far left (IC and WC). Count to 10 and turn the power back on.
  • The IC terminal below two computers is almost unreadable, but after a few seconds it will seem to be asking you something. Answer "2" (for Lowell 2Kx2K system). It will beep happily at you for a few seconds.
  • In the control room, log on to the WC terminal. Answer "2" to the (eventual) prompt for the system. Answer "y" to the question as to whether the IC is up. (The IC system has to be up and running before you restart the WC, but if you do things the way I've described, this will be the situation at this point.)
  • After each reboot you will need to fix the following:
    • Set the binning to 2x2.
    • reset the filter ("N filter") to ensure that MOVE and the WC are in accord.
    • Type "+store" to make sure that images are saved to disk.
    • Specify the directory and file name of the next image. (For instance, if you wish the images to wind up on the SUN (Hall) in a directory /hall/data/pcdata/phil with an image name of "j.001" then type: filnam e:\phil\j.001). If you've rebooted in the middle of the night, you will need to be careful to specify a sequence number greater than what you have previously done.
  • Log on to the SUN Hall and make sure the directory you've specified exists, i.e., mkdir \hall\data\pcdata\phil
  • Take a bias frame to substantiate everything looks reasonable:
    • bias test
    • go
    • The image will be displayed on the SONY monitor, and you will also see the average count rates on the WC monitor. Typical bias values are around 180 ADUs.
• If this is the first night of your run, update the filter list and observer names on the WC:
  • observers Massey, Hunter, and Spot
  • "listf" to list the filter names and positions
  • To update a filter name, use: "N 0 deff filtername", i.e., "2 0 deff B" will associate the name "B" with filter position "2".
• If this is the first night that the instrument is on, set the focus to the approximate value. The focus depends upon temperature (4.0 volts on a cold January night; 1.3 on a warm July evening; a focus difference of 0.025 is a good focus quantum). Check the whiteboard for recent focus values.

Taking Sky flats

• Turn on tracking (tr) and automatic dome control (dm) on MOVE.
• Upstairs, move the telescope about an hour east of the zenith using the handpaddle.
• The first "U" sky flat can be taken a few minutes after sunset:
  • On the WC, type "flat U sky flats" to set the image type to flat, and to specify the name.
  • Type "5 seconds" to specify the exposure times. Exposures shorter of 3 seconds will show a >1% difference center to edge; see Ted's memo for details.
  • go
  • The most important thing in successfully taking sky flats is to sit on your hands; touching the keyboard during an exposure or readout guarentees you will have reboot the CCD system. Upon the second "Working" message the image stastistics will be display on the monitor; values > 55000 are saturated.
  • Once the values are <55000 you are in business. Quickly move the telescope a few tens of arcseconds by holding down the set and E buttons (say) on the handpaddle. Take a another exposure, increasing the exposure time as needed.
• After 3 or 4 exposures (moving the telescope in the same direction as each one reads out), change filters and repeat.

Setting up the beginning of a night/run

• The first step is to find a star, center it on the CCD, and update the coordinates:
  • On MOVE use "pp" to go to a 7-9th mag star.
  • Take a 3 second exposure through V (say). On the WC:
    • 3 seconds
    • 3 filter
    • object test position
    • go
  • As the image finishes reading out, see where the star falls on the Sony monitor. The "+" marks the center of the SITe CCD, and the orientation is marked (N up, E to the left). Use the handlepaddle to adjust the telescope position and take another exposure, until you are satisfied that the star is centered. Use "uc" on MOVE to update the coordinates.
• The next step is to set up the guider.
  • If this is the first night of the instrument block, you will need to do a complete guider reinitization. The instructions for this can be found in Larry Wasserman's documentation here. The steps consist of:
    • Find a 2nd mag star.
    • Do a GFS to put the star on the guider field. If this doesn't work, followthe MOVE documentation instruction.
    • Do a GOS on a fainter star to set the approximate scale and orientation.
    • Do a GEG to determine the scale and orientation accurately.
  • Whether or not this is the first night of an instrument block, make sure that the guider zero-points are good enough to let you find guide stars:
    • Do a ggs and select a guide star.
    • Run "gso" to move the star to the center and zero the offsets.
    • Check by moving the telescope to another star using "pp", center it up with the handpaddle, update the coordinates if need be using "uc", and then use "ggs" to find a guide star. My experience is that guide stars will come up reliably after that; if they begin to be systematically off, check if the telescope coordinates are also slightly off.
• Check the focus. The focus value for BVRI are the same; the focus for the liquid copper sulfate U filter is +0.050 volts different than for BVRI. The focus changes significantly with temperature, with larger values needed as it gets colder. When focusing always make the motion towards larger values. A typical quantum step for focusing is 0.025 volts. Consult the white board in the control room for recent values.
• You are now ready to observe!

Typical Observing Sequence

• Enter the coordinates into MOVE using "co"; hit CR to move the telescope there.
• Acquire a guide star if you will be exposing more than 100 seconds or so:
  • type "ggs" on move, and select the brightest star.
  • If the star appears on the screen, use F4 to move the box to the star, and F2 to start guiding.
  • If the star doesn't appear on the screen, either select another star from the ggs list, or else return to the command level and use "gxy" to hunt around for it. When yo find it, use "glk" to begin guiding.
• On the WC:
  • Change filters via "N filter", where "N" is the filter number.
  • If you're concerned about the focus, check it.
  • Specify a title via "object (title)".
  • Specify an integration time via " seconds".
  • Start the integration with "go"

Displaying and interacting with the image using IRAF

• Create for yourself a nice, large, quiet area on hall where you are unlikely to be distrubed; e.g., "mk /hall/data/pcdata/mememe", and cd to it.
• epar the task "tosun" to specify the subdirectory and root name where the raw images are appearing; i.e., "/hall/data/pcdata/phil/j" for the case that the filename known to the WC is "e:\phil\j.005". Also specify what iraf root name you want for the images (such as "j").
• Run "tosun" specifying the file extensions you wish to translate to IRAF files; i.e., "tosun 5 10" to move over images j.005 through j.010"; the images will be named j005 through j010 in this example.
• Use "display j005 1" to display image j005. Use "imexamine" and the "r" key to display a radial profile of the star.

Closing Down at the End of the Night

• Use "ho" to send the telescope to its home position.
• "qu" to exit the MOVE program.
• Upstairs, close the instrument shutter, and the mirror cover, and then close the dome.
• Turn off the main power.
• Fill the dewar.

Problems and troubles

• If you get any error messages on the WC terminal, or if your images look weird, the first recourse is to reboot the WC and IC; see above. After rebooting remember to:
  • reset to 2x2 binning
  • reset filter
  • reset exp time
  • reset object
  • reset filnam (watch file number)
  • +store
  You should be back in business.
• The dome position appears to get systematically off after tracking through the north-west. It's a good idea to go up and check the dome position if you're concerned about photometry. To reset the dome encoder, do a "dm" (to turn off dome tracking), followed by an "id". After the routine completes, turn dome tracking back on ("dm").