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GLA(NCE)/GFILE - A trial exposure

What this command implies is:

1. Clear the chip unless NOCLEAR flag is set.
2. Pre-flash if non-zero-preflash time set.
3. Expose (open shutter, time exposure, close shutter)
4. Read out chip
5. Reset the pre-flash time to the default
6. Display data on Lexidata.

The data is not recorded as an observation unless you issue the command KEEP after GLANCE has finished.

The GLANCE file thus created is copied into the file called CCDXYZ.000 where XYZ are the user's initials as declared at sign on or by OBSNAME. It can also be referred to as R0 where R stands for Run.

Parameters

A single parameter, the exposure time in seconds, is expected. If omitted, it will be prompted for.

Examples

Adam:> GLANCE 1.5

Perform a GLANCE run with 1.5 seconds exposure.

Notes

During the GLANCE run (which will normally be short), nothing else can be done on the ADAM terminal.

If the exposure time is zero the shutter is not supposed to be opened at all.

BUG: in fact, the shutter opens for about a millisecond.

If R0 gets accidentally protected i.e. it cannot be overwritten with the next GLANCE file then do:

Adam:> PURGE R0

Adam:> GFILE

Note GFILE allocates a new GLANCE file, and can be used any time that the GLANCE file, R0, has been lost.