CHARM is a tip-tilt tertiary system for the Calar Alto 3.5m telescope. It is an addendum to MAGIC our infrared camera., hence the acronym Camera High Angular Resolution Module.
ing world of adaptive optics
CHARM is a tip-tilt tertiary system for the Calar Alto 3.5m telescope. It is an addendum to MAGIC our infrared camera., hence the acronym Camera High Angular Resolution Module.
The brief description of CHARM is available as pdf file.
The figure shows the optomechanical setup of CHARM (click on the image for a more detailed view):
The two folding mirrors and the tip-tilt pupil mirror are inside the mounting flange of MAGIC. They can be moved remotely in and out of the beam. The original and the reimaged telescope focus are in the same position. Thus, if the seeing is too bad to make any use of CHARM, the folding mirrors can be moved out of the beam at a mouse click.
The improvement in peak intensity and FWHM is displayed in the next figure. The images were taken at 2.2 microns with MAGIC in high-res mode:
Under good seeing conditions ( 0.76" at 2.2 microns) the peak intensity is increased by 70% and the FWHM is reduced by 40%.
CHARM is available for the f/45 secondary on the 3.5m telescope. In the visible, the guide star has to be within 1 arcmin of the science object, the limiting magnitude is about 14. If the subarray readout mode of MAGIC is used to guide on an infrared star the limiting magnitude is about 10.
