An extreme AO celebrity!

On Friday December 3, during our daytime engineering run at the telescope, our own Vincent Garrel was interviewed by a Japanese TV crew... groupies are becoming a problem while working at the summit of Mauna Kea: too much excitement combined with the lack of oxygen causes too many accidents.

Pictures of the frame

A picture is worth a thousand words... in a deliberate effort not to overwhelm you with too much information, I will therefore just let you enjoy the pictures of the finally assembled frame! But before that, let me thank Doi-san for his great design and work on the frame: very nice job, Yoshi!

Pineapples, pineapples!

On my way back from NY last Sunday, I played with my Python SCExAO simulator to get a feeling for how a phase map on the deformable mirror (DM) gets remapped by the PIAA. The grayscale picture shows the focal plane image resulting from a double cross sinusoid on top of a flat DM. Without the PIAA, you expect to see your usual PSF surrounded by a regular grid of speckles whose separation depends on the number of sine waves you can generate across the DM and whose brightness depend on the amplitude of the sine wave. If the guys from SEEDS read this post, this may remind them of what the grid mask they want to put in HiCIAO will do...

With the PIAA, things of course get really different and your regular grid gets turned into a nice display... of pineapples! I just showed this morning the corresponding picture to a friend who was staying at our house. The laptop was on the kitchen table, and half joking, he pointed out that the picture looks just like the Hawaiian quilt pattern that's printed on the the kitchen tablecloth asking me whether I had done it on purpose... what do you think?

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).

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.

SCExAO Frame delivered!

Last week, the frame that will carry SCExAO when at the telescope was finally delivered to Subaru HQ! The big white painted welded steel structure that looks sturdy enough (thanks to Doi-san for the design!) now sits in the Subaru Simlab, ready to host the SCExAO bench, the HiCIAO camera, all of the necessary electronics and computers with spare room at the Subaru Telescope IR Nasmyth platform.

There is still a fair bit of work to be done on the frame: attachment holes to be drilled, pads for the frame resting on the floor and rails for lateral positioning of the instruments... but this is a big part of the project and having it finally delivered after over a year of discussion and design is quite a relief!

Good and bad news for SCExAO

No post in January... what's going on with the project? Let's start with some good news: in December, the SCExAO project was reviewed by a Subaru Telescope committee. Late January, the review report was sent to the Director who recommended to give SCExAO at least one night in the semester S10A, likely in May or June, before the telescope summer shutdown for re-coating of the primary mirror... yes!

The bad news is that only two days after this decision was announced, Subaru's AO system experienced a major problem, which permanently damaged the deformable mirror, making it unusable. The AO group at Subaru is working hard on trying to bring the AO back to life, however the replacement mirror won't be delivered before the end of October, which means that SCExAO is unlikely to go to the telescope before 2011.

While this is clearly a disappointment, we just have to make good use of this time. We have plenty of things to do: integrate and test the new frame for SCExAO and HiCIAO, which should be delivered toward the end of February (this month) is a major item on the list, write and polish the existing software for the control of SCExAO is another.

A hui hou!