4. Card Decks

	Once you have decided on the methods you wish to use to
observe, you must prepare either a "Setup" or a "Source" deck.
Historically computer cards were used to prepare the observing file.
Presently a PC is used to simulate a card reader; however files may be
transfered to the PC using FTP.

	Files must contain lines that are 80-82 characters
long; carriage returns, line feeds or other characters in columns
81-82 are ignored.  Columns 1 - 80 must not contain lower case or
special characters like tabs, escape sequences, carriage returns, or
line feeds.  We support double-sided, double-density (2S/2D), 5 1/4
inch floppies.  File-ed, a menu driven editor available on PC's at
Green Bank, can help first-time users of the telescope in creating
observing files (documentation attached to the CAO).  You can use
Checker, a program available on the PC to examine decks for errors.

	Regardless of the physical medium of the deck, the term card
in the following discussion will mean either a computer card, a record
in a tape file, or a line in a floppy file.  The rules and regulations
on what these cards must contain and examples of decks are given in
Appendix A and B, respectively.

a.  Setup Cards and Decks

	All observers must prepare "Setup" cards that tell the
computer how to set up the hardware or how the hardware has already
been set up.  The deck consist of an "O" card, up to four "R" cards,
"A", "L", P", and optional "C", "D", and "Unlabelled" cards that are
formatted exactly as shown in Appendix A.

	A deck consisting of only "Setup" cards is a "Setup" deck and
is for interactive types of observing programs using the operator's
console.  Interactive observing can be very powerful for very short
list of objects that are observed for long stretches of time.
However, we only recommend observing >from the operator's console to
seasoned veterans of radio astronomy.  Most first-time users of the
telescope should prepare "Source" decks and run their observing
program under computer control.  The CAO and "Friend of the Telescope"
will provide help to those who want to observe from the console.

b.  Source Cards and Decks 

	A "Source" deck consists of "Setup" cards followed by source
("S") cards containing information like the name, position, velocity
for the objects the observer wishes to look at, and the name of the
procedure to use for the observations.  You can change a "Setup"
parameter in the middle of a "Source" deck by inserting the new
"Setup" card at the location in the deck where you wish to make the
change (examples in App. B).

	Since the operator cannot change observing parameters when a
"Source" deck is used, the deck must contain all the necessary
information.  Observations can start from any card in the deck, and
will proceed down the deck until the operator manually terminates the
observations or the end of the deck is reached.  You can jump back and
forth within a deck.