Jared Males – Page 53 – Extreme Wavefront Control Lab

MagAO goes to ABOR

Last week Laird and I had the pleasure of attending the Arizona Board of Regents meeting in Phoenix, and presenting a poster about the Magellan AO system and the VisAO camera. The session we were invited to was on the impact of scientific research on student’s education at Arizona’s universities. Click the image below to download the poster as a pdf. It contains an introduction to AO in general and visible AO in particular, as well as an overview of the MagAO project. We also took the opportunity to show off some of our exciting results from the test tower in Florence.

Males et al 2011, ABOR Poster — Click to download a pdf

Our Filters

We are about to start posting some very exciting results, so I thought we should provide some information about our filter system. We are using Sloan Digital Sky Survey (SDSS) standard r’, i’, and z’ filters as our main bandpasses. These filters were provided by Asahi Spectra. Our CCD47 has a near-IR coating to maximize its long wavelength quantum efficiency (QE). The below plot shows the combined QE of our system (taking into account only the CCD and filters), as well as the mean wavelengths of the filters.

Magellan VisAO Filter Curves — The tranmission of our SDSS bandpass filters and CCD.

Update 22 July 2011: added the transmission of our 950 Long Pass (950 LP) filter. This should be treated with a little caution, as it is from a catalog page, and not a measurement of our actual filter. Also note that these calculations were done assuming our CCD47 QE goes to 0 at 1.1 microns, since the manufacturer’s curve stops at 1.05.

Magellan AO Fit Check Pictures

Pictures from the fit check have been posted on flickr by the Magellan Observatory. Here’s a photo of the PI hard at work tweaking the handling cart.

Laird Drills a Hole — Just pretend it's a grad student . . .

More at their flickr page

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

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.

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.