Our Mirror is a Mirror

On March 10, 2011 the MagAO secondary shell had its frontside successfully aluminized at the University of Arizona, Steward Observatory coating facility in Tucson by Richard Sosa and Gary Rosenbaum. This also took a lot of hard work by Jason Lewis and Victor Gasho.

Magellan ASM side view
The side of our freshly aluminized 850 mm diameter adaptive secondary for MagAO. This shell is just 1.5mm thick with 585 magnets glued on the back.
The Magellan ASM
The newly coated front of the secondary.
Victor and the ASM
Project Manager Victor Gasho reflected in the secondary
Laird and the ASM
A relieved Principal Investigator Laird Close reflected in the secondary.

White light PSF

i' PSF

After completing our work with the laser, we switched to a white light source to test the camera’s performance in broad band filters. This is our PSF in the Sloan Digitial Sky Survey (SDSS) i’ filter (a nice set of filter curves is here), which passes light from roughly 0.684 to 0.840 microns. A theoretical Airy pattern is shown for comparison, and Laird calculates our Strehl ratio as 94% – meaning that our optics are very good.

i' PSF
The Magellan VisAO i' PSF

This image is taken without the ADC in the beam. In the laboratory, without the dispersion of an atmosphere to act against it, the residual chromatism of the ADC would slightly degrade the image quality of a broadband source (see Kopon 2008). This “zenith spike” effect was predicted and does not manifest itself on-sky.