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MULTEXP - Perform a multiple exposure on a single frame

This is similar to the FOCUS command except that focus is not changed and the images are equally separated (by 20 arc seconds if the default OFFSET is in operation, or by the defined value of OFFSET - see subsection 3.3.6). It is useful for observing photometric standards because several exposures can be made in quick succession to check the sky conditions or to increase effective signal/noise since only one chip readout is involved.

Parameters

The number of exposures required

The exposure time (in seconds)

The direction in which the image moves on the chip (N,S,E,W)

These are all prompted for.

Examples

Adam:> MULTEXP

and follow prompts.

Note that the resulting frame has the same status as a GLANCE file and must be kept using the KEEP command. The FITS packet information does not at present record the shutterexposure time for each exposure - only the first. Thus it is recommended that these be copied from the screen as they appear if needed - alternatively the ADAM log can be printed for your notebook after each such frame. This is done by issuing:

Adam:> SHOW LOG/LINES=50

and putting the line-printer on-line.

dxc@mail.ast.cam.ac.uk
Wed Mar 16 03:14:28 GMT 1994