• Frame Type SCIENCE_CORONOGRAPHY
• DPR.TYPE OBJECT; SKY
• DPR.TECH IMAGE,JITTER,APP,CUBE; IMAGE,JITTER,APP,CUBE,PT; SPECTRUM,NODDING,APP

description: A new coronographic Apodizing Phase Plate (APP) has been offerend since P86. It is mounted in the OPTI3 wheel (INS.OPTI3.NAME=APP_coro) and designed to work in the 3-5 um range. It is offered to work with the filters NB_4.05 and Lprime. The IB_4.05 filtered showed problems and is now decommissioned.

Since no occulting mask is present in the focal plane, it works like simple, direct Lprime imaging. This new observing mode is suitable for searches of faint companion as it provides higher contrast at small angular separation - from 0.2 to 0.7 arcsec from the main star on one side. It can be combined with cube mode and pupil tracking.

For more information regarding APP coronography consult the NACO User Manual

This is an example of the APP coronographic observation in filter NB_4.05. The picture is just a small snapshot of the upper central area of the detector region.

This mode is offered in visitor mode. It is not supported by the pipeline.

calibrations:The calibration plan includes

• standard detector darks with readout mode and DIT matching the one used for science;
• standard sky flat fields without the focal plane mask;
• sky flat with APP mask in the focal plane (DPR.TECH=IMAGE,APP);
• nightly zero points - optional;