GBT long-term timing instructions

1. Contact numbers:
   GBT Control Room: 304 456 2346,304 456 2341
   
2. Connecting to GB (~15min before start)
   1. First step is to get a VNC connection open:
      • Log into ssh.gb.nrao.edu as yourself, then from there ssh to titania.
      • On titania, run "vncserver -geometry 1000x700"; feel free to adjust the screen geometry, etc to your preference. Look and see what the vnc session number is (ie, titania:3).
      • On your local machine, run "vncviewer -via YOU@ssh.gb.nrao.edu titania:N" where YOU=your acct and N=vnc session number.
      • You should now have a GB vnc desktop on your screen. All steps from now on will be done on this desktop.
   2. Next, open a chat (Talk and Draw) window.
      • Open a xterm, and run "cleo". When the menu comes up, select "Launch->Utilities->Talk and Draw" to open a chat window with the operator. If no one is responding, call the control room.
   3. Open Astrid
      • Run "astrid" from your GB xterm. If it is still before the obs start time, select offline mode. Otherwise select online with telescope control.
      • Go to the Run tab, then select GBT06A-054 in the Project field. You should see a bunch of scheduling blocks appear with the names of our sources, along with setup and cal off/on blocks. Put your name in the Observer field, and select the current operator as well.
   4. Open gbtstatus
      • Get a new xterm, make it pretty big then run "gbtstatus". This will give you current pointing info, etc, etc.
   5. Setup GASP connections
      • Open 3 xterms. In each, do "ssh -Y gasp@gasp0"
      • In one, cd to /home/gasp/data/GBT06A-054. This is where output data files go.
      • In another, cd to /home/gasp/config/ltt. This is where config files are.
      • In any gasp xterm, run "setif GBT".
3. IF Setup
   1. Get telescope control
      • Once the operator says its ok, switch astrid to control mode. From the File menu, choose "Real time mode" then select "online with control of telescope" from the dialog box.
   2. Run setup script
      • Again, wait for the operator's ok before going on; he/she will deal with selecting the correct feed which may take a few minutes.
      • From the Astrid run tab, click on the appropriate setup block for today's freq, either 000_Setup_1400 or 000_Setup_0820. Then press Submit. You will see a bunch of messages go by in the bottom window, eventually ending with "Telescope configured correctly" or something along those lines.
   3. Check power levels
      • Look at the bottom of the gbtstatus window. You should see several lines, two of which will start like:
        IFa: 1.000 CM11: 0.050 GASP...
        IFb: 1.000 CM15: 0.050 GASP...
        (If you see nothing like this, make the window taller) "a" and "b" will be numbers which change depending on receiver. The "1.000" will be the IF power levels; these should be around 1.0 for 1400mhz or 2.0 for 820mhz. If they are too big, run the "000_Balance_IF" block in Astrid.
      • In one of your gasp xterms, do "ssh cpci -l root". The password is "seti". On cpci, run "set_gain 0 0 ; set_gain 1 0" to zero out the gain. Then run "rms" and look at the levels. Adjust each poln as appropriate by running "set_gain (pol) (gain_in_db)". The range for gains is -18 to +25 dB. When done, exit cpci.
4. Pointing to sources
   1. Check schedule
      • The observing schedule is at the end of this document.
   2. Point telescope
      • In Astrid, select the source to go to in the Run tab, then hit Submit. This will start the telescope slewing. Once on source, the script will automatically balance the IF and turn the cals on. Watch gbtstatus to find out the slew time, etc.
5. Run GASP
   1. Copy config file
      • In the gasp config dir, find the appropriate config file, they are named config.(psr_ra).(freq).xml .. Ignore the ones with "cgsr" in the filename. Edit this file to remove any dead nodes, etc, as usual. We do cals first, so make sure calscan is set to 1. Set integration time as appropriate given the schedule.
      • Put it in the correct place by running "cp (config_file) $ASP_CONFIG_FILE"
   2. Run cal scan
      • In the gasp data dir, run start_asp. In another xterm, run stat_msg. When you see "Start MJD=..." you can run stat_asp in your 3rd xterm. If the 2 MJDs are different, stop all these programs with control-c then repeat this step.
      • When the cals are done, exit stat_msg via control-c.
   3. Run data scan
      • Make polycos by running "makepoly" in /home/gasp/runtime. Save the polycos by concatenating into a big file for the day you are observing.
      • Turn off cals by selecting 000_cal_off in Astrid and hitting Submit.
      • Edit $ASP_CONFIG_FILE (NOT the original copy in /home/gasp/config!) to set to 0.
      • Start taking data as before (start_asp, stat_msg, stat_asp). Same comment about the 2 MJDs applies here.
      • When it's time to change srcs, datataking can be stopped early (if needed) with control-c.
6. Coordinating with CGSR
   1. If someone (probably Bryan) is running CGSR simultaneously, you will need to coordinate with him to make sure he is done with cals before you turn them off. Also check when ready to change srcs. Talk and Draw is good for this.
7. Schedule - depending on the exact start/stop times, you may need to skip 0218 and/or 2124.

   Source start_lst
   0218+4232 09:50
   0613-0200 10:30
   1012+5307 11:10
   1442+101 11:50 (Cal Src)
   1455-3330 12:10
   1643-1224 12:50
   1713+0747 13:30
   1744-1134 14:10
   1937+21 14:50
   1821-24 15:20
   1918-0642 16:00
   1909-3744 16:40
   2145-0750 17:30
   2124-3358 18:20