March 2013 – Extreme Wavefront Control Lab

Comm2 Day 7: First night on sky went well!

Tonight we closed the loop on-sky, on Kate and T.J.’s first night here this run.

We were able to use the new pupils we calibrated over the last few days, and Marco’s new interaction matrix, to close the AO loop with 378 modes. This was a big step forward! The wavefront error was close to 100 nm rms in 0.5-0.7″ seeing. This is our best correction yet!

Dusty — Closed loop image of V~5 star at 980nm wavelength with coronagraph on VisAO.

3.4um Narrow camera — Clio display and Vanessa with a beautiful diffraction-limited image.

See, the loop was closed — AO WFS and ASM display.

Ballpark super good — Focusing Clio in various filters as well as the APP.

Happy Easter

Comm2 Day 6: Nighttime Edition

You might have noticed that our server redirected you to https. This will help ensure that MagAO continues to be a source of good, clean, family-friendly fun. Thanks to Paul Hart for helping Jared get a certificate set up.

Lovely backdrop! — KT saw the Zorro by the dining hall mid-morning. He was not shy at all, and let her get pretty close to get a good picture. Our telescope, the Clay, is in the upper right of the photo, it’s the left-most telescope of the big pair.

A dog under 40 lb is a cat, and cats are pointless — If you are worried about Vizzy when a fox is out and about, note the size of Zorrito as compared to the cars here — he’s very very small.

Thanks to our loyal readers, Jared has found a new source of funding for Arizona’s various AO endeavors:

popularity contest — A comparison of MagAO and Zero (Clio/LBTI/CAAO) domain names. Curiously, though MagAO is ranked lower than Zero, it’s worth more.

Alfio and Marco have been hard at work building bigger and better interaction matricies. By enabling or disabling rings of ASM actuators around the central obscuration, they are able to create more robust, higher quality calibrations. They create different sets of shapes (different “modal bases”) to apply to the mirror, based on which actuators are enabled. The new interaction matricies they’ve taken today have improved the VisAO image quality by ~20%! They also took a full suite of calibrations which will allow us to observe very faint targets.

Chasing away the viscachas. — Alfio and Marco building away. Laird and Jared weigh in.

Today we also moved the Clio solid nitrogen pump down to the basement, to reduce telescope vibrations. The optical alignment of the CRO is so sensitive that we can easily see a 1 micrometer (10^-6 meter) displacement. So we need to take as many sources of vibration off the telescope as we can; pumps are especially bad. The telescope staff routed a ~150ft hose from Clio to the pump’s new home in the basement.

The suckage is relocated. — Vanessa and Laird work on removing the Clio pump from the rack. Katie and Victor attach the new vacuum hose.

The pump is relegated to the dungeon, never to see the light of day again. — We explored the basement after installing the Clio pump in its new home. Upper left: Various cables have to be routed up to the telescope chamber. Lower left: Pato shows off the telescope bearings. The whole telescope floats on a cushion of oil (the blue ring behind Pato). He’s pointing out the bearings and encoders that control the telescope’s motion. Right: To keep the telescope temperature equilibrated, huge fans circulate the air.

We’re T -1 day from going on sky. The whole gang is hard at work finishing preparations to the AO system, VisAO, and Clio.

Laird likes his new Captain's Post. — The Clio gang. Katie writes pipelines for Clio calibration and data reduction. Jared works on VisAO performance analysis tools. Alfio and Marco build a library of AO calibrations. Laird oversees it all.

Tomorrow, two more team members will be arriving: TJ Rodigas and Kate Follette. Just in time for the big debut!

Now it’s time for me to follow Povilas’ lead…

Quotes:
“You drive me to caveats” — Povilas
“Now the entire blog is staged” — Katie (after Povilas admitted that he said that just to get on the blog. He loves us.)
“Nature throws thing at you that are not Kolmogorov. That’s a major caveat.” — Laird
“Maybe we should go back to the old interaction matrices. If the Strehl is too high, it might melt VisAO’s CCD” — Jared
“Cheese helps me to concentrate” — Marco
“Well… is the Clio pump on?” — Laird (asking completely sincerely!), blaming Clio for vibrations even after we stuck its pump down in the bowels of the telescope
“I have control over everything” — Alfio
“If you can’t focus a camera then you shouldn’t really be going on-sky with it” — Laird

Comm2 Day 5: Bear Down

Well the Wildcats lost to the Buckeyes this evening, but take heart, Arizona, things are looking up for us MagAO’ers down here.

The main highlight of today is that the AO system is running closed loop on 0.8″ simulated seeing at 1 KHz sample speeds (where we were at the end of Comm 1). We have 300-325 modes running with a brand new (better) basis set of Fernando that will hopefully work on sky (which would be an improvement over the 200-250 modes achieved on-sky in comm 1). We’re going to keep the CRO on tomorrow night to take the time to get our interaction matrices and camera focus positions right… but everything seems to working well.

Sight for sore eyes — The loop closed with beautiful Pyramid pupils on the right and a beautiful red-optical PSF on the left.

There was also a VIP guest tour of AO operations today, and the guests were “more excited than undergrads” (as Vanessa put it) when we demonstrated closing the loop.

yeah — Jared wows the crowd with a closed-loop demonstration, and some exciting images

neat — KT impresses the crowd with her planet image.

Vanessa and I have been working on all sorts of housekeeping and optimizing Clio tasks…

was it just yesterday? it's been a long week already... — Vanessa and I standing by Clio after it was mounted the other day

Of course the zoo is still hopping here:

the bells — A guanaco gazes at Las Campanas Peak, visualizing the future GMT on the now-flattened mountain

Not so Grumpy Vizz — Marco caught this awesome shot of Vizzy curling his tail, squeaking, and watching the sunset. We call this a “wild vizcacha” since he’s not at the Astronomer Support Building as is his wont, but is hopping about the landscape.

“You should show them the chaos that is MagAO” –Dave
“Sitting through an earthquake here feels like observing at the MMT” –Laird
“It’s the Wild West — It’s Cowboy astronomy” –Katie & Vanessa

Comm2 Day 4: Happy Birthday Alfio!

Today is Alfio’s birthday.

older, wiser, and orthogonal. — I hope it was happy, and we’re glad you’re here man.

As you can see in the above picture, we have a new minimum-force basis set to try (thanks Fernando!). As soon as we get everything lined up, we’ll test it on the CRO.

Speaking of the CRO, yesterday was crazy. So crazy that none of us had much energy left (at 1am) to write a long ‘splainy blog post. So here’s a little more about what was going on. The CRO is a tiny mirror inside a cup, which has a pinhole on the top. The CRO is suspended at the focus of the ASM, and we send light from an artifical star inside the W-unit up to the secondary, which focuses it into the pinhole, and the CRO reflects it back to the secondary exactly as it came in. CRO stands for Calibration Return Optic (note: it is NOT a retro-reflector! (right Alan?)), both C-R-O and Crow are considered correct pronunciations.

The CRO pinhole is very small, so we have to have it exactly on the optical axis of the telescope. To align it, we use two crosses, one at the W-unit itself, and one on the back of the CRO. The real magic, thanks to Armando and company, is to use a digital camera with a wide focus range to first focus on the W-unit cross, then on the CRO cross, and move the camera until the two crosses line up. From there we move the CRO itself until the reflection from the CRO is lined up with the crosses.

So, step 1 is: Make crosses. In Katie’s post yesterday you saw how the cross was made on the back of the CRO. We also had to re-make the cross on the W-unit. Armando made one using some wire and a rubber band to keep it tight, but the rubber band disintegrated over the last few months. For some reason, it fell to me to attempt to re-create some fine Italian craftsmanship:

don't worry, she still had her pink safety shoes on - so still stylish — We replaced the rubber band with Katie’s hair tie.

Step 2 is: Line up the CRO secondary and instrument axis using the cross at the instrument and the mark on the bottom of the CRO.

Alla Armando — Alfio and Marco set up Laird’s camera on Vanessa’s tripod to check the alignment of the CRO.

Step 3 is: move the CRO (this time by moving the secondary vane-ends) so that the reflection of the measuring camera itself. off the secondary, is centered on the crosses.