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N.B. This mode is not currently offered
Coronagraphy can be used with any Imaging Filter
See also the Predefined Coronagraphic Modes
The diameter of the coronagraphic mask is 1.2". The coronagraphic mask is located in the slit wheel and can be replaced by a MOS mask if demand for MOS is high.
To get into coronagraphy mode:
Two occulting spots, 1.2" diameter, are available, one in the upper left, the other in the lower right quadrant. The source can be centred behind one of the two masks using:
If you are not happy with the alignment, ask the OSA to make small offsets in the desired direction. Note that you have to be guiding in order to ensure that the source stays behind the mask over longer times. You should already be autoguiding before you make fine correcions.
WARNING: The lobject_inslit command will NOT WORK for zenith distances larger than 75 degrees (airmass ~4). The flexure of LIRIS has not been measured for such angles. If you really want to observe at this airmass, then ask the OSA to bring the object onto the mask.
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