The comment card
Very simply, the comment card begins lines which have no effect on observations, but do have some prescence in how we catalog and interpret files.
Operational applications
- As used in line #5, the newfetch program parses start time from this particular standard comment card and uses it as a starting point for calculating azimuth and elevation of sources in the fetched file summary.
Caution! Some much older versions of Observe, as well as some 'handmade' files may not have the standard start time format in line #5. In this case, invalid azimuth and elevation may be given for the first source card only, perhaps leading to you believe the source is unreachable; subsequent source cards will use the stop time of the first card and correct this discrepancy.
- Comments following the ID card, and preceeding source cards, will not print on LA1 at the start of a file. However, comments embedded between source cards will be printed - at the source change prior to the source card they follow! (ie, the system 'looks ahead')
Common problems
The most common mistake encountered in comment cards is the elimination of the first space following the *, example:
//*This is not a valid comment!
//* This is!
In the first case, file check will respond with an 'unknown card type' message.