Thursday, April 22, 2010

Modeling of SCExAO


Building the actual thing is not enough: a numerical model of any experiment is also essential to understanding what's going on inside... SCExAO doesn't escape this general rule and we are working on this model these days!

Doing this is always very interesting and really makes you think about the minute details of all of the optics that currently lie on the bench. And SCExAO involves some pretty tricky components: pupil remapping devices like the SRP, the PIAA and the inverse PIAA are really peculiar optics, and the deformable mirror is a surprisingly complex little thing... but we're getting there!

Just like with the experiment control GUI, we've decided to program this model in Python. It's just been a couple months since we started playing with this, but the deeper we dig, the more we find! Numpy, Scipy, Matplotlib and Pyfits form together a great scientific programming environment that, once you get used to it, does just as well as IDL, which I have been using for the last couple of years.

The picture shows the kind of things this simulation produces: point spread functions (PSF) for different off-axis sources (1,5,10 and 20 lambda/D). Although not finely tuned yet, the model nicely reproduces the pineapple-shaped PSFs that SCExAO generates for off-axis sources with the PIAA only, as published by Lozi et al. (2009).

Wednesday, April 14, 2010

Frame update


I just thought I'd share some updates on the construction of the frame. While some parts are being made at the machine shop, Doi-san is assembling others to the frame... Today, he is working on the vibration damping system that will hold racks for the electronics of SCExAO and HiCIAO.

About two hundred holes need to be drilled to the frame to attach this very cool contraption by Yoshi Doi-san.

By the way, Yoshi is also a talented musician who plays Hawaiian music: ukulele and slack key guitar, and makes his own music instruments. You can follow Yoshi's musical adventures on his Youtube channel.