Change the set of feature markers to be recorded in the archive.

Arguments:

FeatureChange change

What to do with the specified set of feature markers, from:

• one - Add them to the set of markers that are to be recorded in the next frame.
• add - Add them to the set of markers that are to be recorded in subsequent frames.
• remove - Remove them from the set of persistent markers previously added with the add argument.

Features features

The set of features to use arcording to the above argument.

Example:

The following example sets feature bits 0 and 10 of the features register for one archived frame period.

  mark one, f0+f10

Example 2:

The following example sets feature bit 2 in the archive and leaves it set for five minutes before unsetting it.

  mark add, f2
  until $elapsed > 5m
  mark remove, f2

Example 3:

To remove all marks type:

  mark remove, all

Context:

The mark command provides a way to highlight one or more archive frames as special in the archive. There are two ways to do this.

1. One can ask for a single frame to be marked as special. This is used during optical pointing to mark the time when the user thinks that the pointing star is centered under the cross-hairs.
2. One can mark all frames over an extended period by telling the system when to start including a given marker and later when to stop including it. This is to mark calibration observations.

In both cases the specified features are guaranteed to appear in at least one frame, even if a persistent marker is added and then removed before the next frame is assembled for recording.