Christoph Keller and Claude Plymate
Overcoming the atmospherically limited image quality at the McMath-Pierce main telescope is the most important step that can be taken to improve the scientific quality of infrared observations between 1.5 and 12 microns. To that end, a low-order adaptive optics system for the infrared will be implemented at the McMath-Pierce main telescope over the next few years. The development will progress in small steps, starting with tip/tilt correction and progressing from slow wavefront correction to fast correction. All hardware will be based on commercial, off-the-shelf components.
|Caption: The lenslet array (left, above), provided by R. Radick (AFRL), feeds 306 sub-apertures for Shack-Hartman wavefront analysis to provide fast tip/tilt correction to the McMath-Pierce Telescope. In the image on the right, each sub-aperture shows a small sunspot and a white line indicating the local wavefront tilt.|
During the last few months, we have successfully demonstrated fast tip/tilt correction by using a spot tracker. This included implementing an experimental Shack-Hartman wavefront sensor with 306 sub-apertures that measure the wavefront at 950 nm using a ZIMPOL CCD camera. These measurements will be used to measure fixed telescope aberrations and seeing in the telescope and in the atmosphere. In the future, an infrared science camera will be added, and deconvolution-from-wavefront sensing techniques will be used to correct its images.