Before Observing

• Make sure that ALFA will be ready for your observations:
• ALFA cover must be removed.

Startup

• Log in: dtusr (password taped to the monitor; ensure openwindows manager is used).
• Start CIMA on-line GUI by right-clicking on screen background.
• User: your name, a1963, select Spectral Line.
• Choose receiver (ALFA), hit "Select Receiver Now", and dismiss the window.
• Load/Save State: load the setup file (a1963_hiline.gui for spectral line observations, a1963_beammaps.gui for continuum maps).
• Pointing control:
• Enter R.A. and Dec (from Martha's schedule file n2903_yymmdd.txt in /share/obs4/usr/a1963/. Look for the line that starts with "Source ra,dec:"). Make sure that the epoch is J2000 and the velocity frame Topocentric. Source name: linedDDMM for spectral line observations and beamdDDMM for continuum maps, where DDMM is the declination (degrees and arcminutes; e.g., lined2146 for a source with Dec=+214641).
  The schedule files are generated by Martha and are good for a particular declination strip, observing mode (spectral line or continuum), on a given night. Note that the LMST time listed will not exactly match the true data taking start time, because of precession and pointing model corrections; for this run, the data taking will start a bit later than the time listed in the schedule. If it looks like the datataking will start when the telescope is not in position (in which case CIMA should give a warning), skip that particular drift and go to wait for the next one.
• Choose beam 0 as center.
• Point telescope. Do this only at the beginning of the night, so that the telescope moves to position while you are getting the rest of the setup ready. In general, you do **NOT** use the point window to point the telescope during a1963 observations; that is done in the FixedAz drift control. But at the beginning of the night, you want to get a head start since you probably have to slew a long way from wherever the last observer left the telescope.
• Set ALFA Rotation Angle according the schedule provided by Martha (n2903_yymmdd.txt) and hit "Send".
• Dismiss this window.
• Source the tcl code. Go to User preferences and:
• Type "source /home/lerner/fixedAZ2_widget.tcl" in "Send to GUI".
• Hit "Send to GUI".
• Type "source /home/lerner/fixedAZ2.tcl" in "Send to executive".
• Hit "Send to executive".
• Dismiss this window.
• Receiver IF/LO Control --> New Improved IFLO Setup:
• Check central frequency f and bandwidths BW:
  • f=1417 MHz, BW=12.5 MHz (all 4 boards) for spectral line observations
  • f=1405 MHz, BW=50.0 MHz (all 4 boards) for continuum maps
• Apply this setup.
• Dismiss both IF/LO windows.
• Backend Control --> ALFA Backend Control:
• Hit "Configure WAPP ALFA" (we use 2 channels and 9 levels).
• Adjust Power - make sure it's right (the numbers on the "Backend Control" widget should be between 0.8 and 1.2).
• Dismiss both "Backend Control" and "WAPP ALFA" widgets.
• Spectral Line Observing:
• Choose "Fixed Azimuth Drift Map" from the pull-down menu. This will now show the "ALFA Fixed Azimuth Drift Map" observing mode.
• Parameters:
  
  • Az(ddd.dd), according to the schedule provided by Martha.
  • Source= linedDDMM or beamdDDMM (see Pointing control above).
  • Epoch= J2000 (see note below)
  • RA(hhmmss), see Martha's schedule.
  • Dec(ddmmss), see Martha's schedule.
  • ALFA Rot. Ang. (deg), see Martha's schedule.
  • Secs= 480 (or 240 for the continuum maps).
  • Loop= 1
  • New FITS(each loop)= 1
  • Calmode= loopend
  • Caltype= hcal
  • Cal Secs= 1
  • Async Secs= 0.
• Hit "Observe".
• Notes:
  • Source, RA, and Dec will usually be the same for all drifts.
  • Epoch is initially "J" because the pointing widget exports only the first letter (so this is the same as J2000). Also: the choices on the pull-down menu are: J2000, B1950, and "Apparent". If "Apparent" is chosen, the coordinates will not be precessed.
  • You can enter the values of the azimuth and ALFA rotation angle before the end of a scan. Hit "observe" after the scan ends to start the telescope motion. Note that the observing mode widget is the one you should update -- under usual circumstances you should not use the pointing control widget to change azimuth and ALFA rotation angle (see "Pointing control" above).
  • The FITS file is currently opened at the end of the loop (or series of loops, according to the "New FITS(each loop)" parameter). Therefore if you abort an observation remember to start a new FITS file (using the button in the WAPP ALFA widget) before hitting "Observe" again.

When Observing

• Between scans:
• Check power levels periodically. Notice however that there isn't enough time to adjust the power levels during the NGC 2903 run because this takes several seconds, and the observing schedule is very tight. Therefore make a note in the logfile if the power levels are not optimal, but don't do anything unless there is a real problem with the WAPPS (in which case you'll have to abort the observation, troubleshoot the problem, and start another scan at the right time).
• Data Monitoring:
  • On Dataview, click on the background and select from the menu:
  • Quicklook Data Display
  • Observers Monitor
  • Array Rotation
  • Frontend Monitor
  • You can open the same widgets by typing on an xterm:
    • /home/aoui/alfa/alfadatawin &
    • /home/aoui/alfa/alfaobswin &
    • /home/aoui/alfa/alfamotorwin &
    • /home/aoui/alfa/alfamonwin &
  • There is another useful widget (still a test version) that summarizes the ALFA instrument status - so that you will not have to look at the numbers on the Observers and Frontend Monitors:
  • /home/aoui/alfa/Test/alfastatwin &