GBT Observing with PAF ADLink Data Acquisition

Starting Data Acquisition System

The first step is to start the PAF ADLink data acquisition system as described here. This step is the same as starting the data acquisition system for stand-alone operation. It will initialize a lot of default parameters that are essential for operation with the GBT. However, once the data accquisition system is started, and you are satisfied with the default setup as it appears on the PAF Rcvr GUI, do not touch this GUI again. Otherwise, you run the risk of overwriting parameter changes from the GBT. Let the GBT control system make all further parameter changes. These will NOT be reflected in the PAF Rcvr GUI.

Observing with the Green Bank Telescope

The essentials of observing with the GBT are documented in the Astrid user's manual. This is highly recommended reading.

Create a Scheduling Block

To create a GBT observing script use your favorite basic text editor, like emacs or vi to create a scheduling block like the following:

mySource = "3C48"
scanLength = 5.0
# Create list of sources available for subsequent procedures.
sources = {
    "1642+3948" : Location("J2000", "16:42:58.81",  "39:48:37.0")
  , "2202+4216" : Location("J2000", "22:02:43.29",  "42:16:40.0")
  , "3C48"      : Location("J2000", "01:37:41.30", "+33:09:35.4")
}
# Configuration string - setup parameters for the GBT Monitor and Control
# system (note you can specify rest frequency)
PAF = """
receiver="RcvrArray1_2"
restfreq=1400
"""
# Activate the configuration.
Configure(PAF)
# Move to the source but don't start data acquisition.
Slew(sources[mySource])
# Prepare for a data acquisition scan.
SetValues("ScanCoordinator", {"source": mySource})
# Begin the data acquisition scan.
Track(sources[mySource], None, scanLength)

The syntax is like Python with a few added constructs unique to telescope control. The hash character, "#", delimits comment text for which the rest of the line is ignored by the code interpreter. The basic changes that you'd need to make to this observing script is to substitute your own source names and coordinates and your chosen rest frequency.

Start Observations

Now you are ready to observe.