CARA Science:


This instrument uses the 60-cm SPIREX telescope as well as a Celestron 11 inch (C-11) mounted on top of the SPIREX tube.

CARA implemented a differential image motion monitor, as described by Sarazin and Roddier (1990), but modified the design by eliminating the prism, adding a Hartmann aperture mask, and defocusing the telescope to image each sub-aperture of the mask. We call this arrangement a Hartmann differential motion monitor (H-DIMM), and described the technique in Bally et al. (1996). With a mask of n apertures, the number of baselines is given as n*(n-1)/2, permitting a highly redundant calculation of the seeing.


See the page on seeing for a brief discussion and plot. See also


For more information

The group does not yet have a website.

SPIREX/HDIMM is based at the University of Chicago, Yerkes Observatory. For more information, contact Bob Loewenstein, .