===== Classical Lyot coronagraphy (CLC) in L- or M-band  =====

===== Operational procedure =====

==== Preparation ====

  * ETC
  * p2pp kind of OB preparation
  * any special needs?

==== Acquisition ====

Template options:
  * [[METIS_img_lm_clc_acq|METIS_img_lm_clc_acq]]

==== Science sequence ====

For HCI observing modes:

  * The target (typically a bright star) is always on-axis and used as the NGS for the SCAO
  * The derotator is always in pupil tracking mode (i.e. pupil is always oriented in the same pre-defined direction)

Sky subtraction:

  * Background subtraction is done by post-processing of the images in pupil tracking mode (e.g. ADI) 
  * An occasional sky frame can be taken by offsetting the telescope (TBD). The AO loop is opened for the sky observations, and then subsequently closed when back on target.

Template options: 
  * [[metis_img_lm_clc_obs_fixedskyoffset|METIS_img_lm_clc_obs_FixedSkyOffset]]


===== Calibration data =====

++++
Calibration requirements|
  * flatfielding (daytime WCU, not needed daily?; twilight sky flats?)
  * sky background recostruction/subtraction (chop/dither/stare), align frames (dithered/choped exposures)
  * flux calibration (sky atmosphere modeling + one/few standard observations per night?)
  * psf re-construction?
  * provide data cube or "stacked" result?
++++

===== Products =====

  * background-subtracted, flux-calibrated image (cube). Units, e.g., [photons/s/pix]
  * corresponding uncertainties (cube)
  * PSF (cube)

===== Discussion =====
 [[img_lm_clc_discussion|img_lm_clc_discussion]] 