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- Go into `Movies' menu. Go into the `Set_movie' menu
and select a movie exposure time (which is independent of the observing
exposure time in your CONFIG), say, 0.5 sec, and a number of movie
exposures per integration, say, 1 exposure/integration. PF1 to exit.
- If you are using ND_STARE mode, go to next item below. If you
are using basic STARE mode you may need to subtract a recent DARK or SKY
exposure before you can see your source in movie mode. If you need to
subtract a DARK or SKY, go into the `Set_graphics' menu, then go
into the Background_subtraction menu. Use either the
Subtract last integration or Subtract specified integration
items to define the DARK or SKY to be downloaded into ALICE and
subtracted prior to movie display. Definition of a background to be
subtracted automatically enables background subtraction. Remember
to disable background subtraction once you are finished with it.
(By the way, don't try and load a different LUT within `Set_graphics'
as it causes the system to crash).
- Select the `Run_movie' item. You will need to
`Abort_movie' before you can exit from this item. In movie mode,
images of the defined exposure time are taken and displayed
automatically on the ALICE movie screen. Note: No data are stored
to disk in this mode.
- Ask the TO to centre the object at the position you require on
the array. Check that the object is not saturated by inspecting the
statistics displayed (see § 5.2 on saturation levels).
If necessary, `Abort_movie' and reduce the movie exposure time and
repeat the above. Because of the hot pixels, you must be careful about
checking for saturation from sky. Rather than looking at the peak count,
try and choose an area of the array relatively free of hot pixels, and divide
the sum total by the number of pixels in the statistics box, to obtain
a mean count. You can also change the display stretch from `nsigma'
to `zero-to-saturation' within `Set_graphics'.
- When you are happy with the source positioning and exposure time,
end the movie with `Abort_movie' option. PF1 twice to return to
`Imaging' menu.
Next: Taking Data On-source
Up: Taking an Exposure
Previous: Initial Setup
Shaun Hughes
Thu Mar 14 14:48:38 GMT 1996