Author: Katie Morzinski

Well, we tried out our faint guide star modes tonight. We locked on a 14th magnitude guide star in bin 3, and a 16th magnitude guide star in bins 4 and 5! We were getting down to 90 milli-arc-second PSFs in K-band, where diffraction-limited is 70 mas, while correcting fewer than 100 modes.

In this image we are locked on a 13th-magnitude guide star 24” from the galaxy (Clio image is below the finding chart).  We would like to thank D.M. for the quick reduction and feedback on our faint guide star work.  This is a big deal!  We were able to lock the AO system on the correct faint star in the field, keep the galaxy on the chip, and deliver a 0.25 arc-second PSF in 1” seeing and 1.7 airmass (about 35 degrees up from the horizon) on a faint guide star for off-axis science!

OK, look. This is a blog about science and engineering, and occasionally animals. But we’re tired. We’ve been here for a long time. It’s all we can do to keep up with our data logs and the infinite list of things to test and implement. So the rest of today is quotes:

The VisAO Data Reduction team trying to figure out their rotator angles:
Laird: “It’s 90 degrees”
Kate: “It’s 270 degrees”
Jared: “It’s 27 degrees”
Laird: It’s 7 degrees”
Kate: “It’s 97 degrees”
Jared: It’s 180 degrees”

Alfio: “Well now I know why that galaxies book I read was heavy on the theoretical modeling and weak on the observations. Galaxies are hard to observe!”

Laird: “Unlike with this galaxy nonsense, we will be able to see the young stellar disk right away!”

Laird: “Guys, just between you and me… and don’t put this on the blog… but …”

Jared: “It’s ok. We have another problem.”

T.J.: “We’re ballpark exactly on the sweet spot.”

Jared: “OK, T.J., I’m about to start saving data here.”
T.J.: “I’ve *been* saving data.”

T.J.: “Squinting is like binning.”

Laird: “High-order AO used to be 8×8”

Jorge: “The sun is rising! I have to close the dome!” (Pause… go in dome… close dome… come back to control room) “…OK, good, no fire!”

The return of the Crow part II:

Edgar Allen Poe—
Once upon a midnight dreary, while I pondered weak and weary,
Over many a quaint and curious volume of forgotten lore…
…Only this, and nothing more:

The excerpt from the poem “The Raven” is brought to you by the Return of the Crow part II.

That is, we put the CRO back on this afternoon, so that we could spend the evening and night making new interaction matrices. We used a new pattern file from Charlie from SciMeasure, and were able to do bins 3, 4, and 5 — the faint modes — as well as testing the chromaticity of the interaction matrices. Tomorrow we will go back on sky to try them out!

We also spent a lot of time making sure we understand our data. We *still* weren’t certain about the orientations of our respective cameras — Jared, Kate, and Laird spent a lot of time disagreeing about which way to rotate the VisAO images to get North up. And T.J., Katie, and Phil spent some time with the Clio FITS headers and with Clio read noise. Our night-lunch sandwiches are wrapped in tinfoil, and T.J. scavenged it to wrap some wires to reduce electrical noise.

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Tyson has left and we miss him — Tyson, when will we see that special blog post of yours?

“I’m not interested in discoveries.  I just want to take data.” – T.J.  (6am after staying up all night)

“It’s a binary. No look, it’s a binary!” – T.J.

Our ranks are thinning — Alan Uomoto left today and I didn’t even get to say goodbye.  Bye Alan!  Thanks for all your help in getting us up and running!!

We are still engineering our many modes on sky and debugging telescope and instrument problems.  One of our exciting new modes is Simultaneous Differential Imaging (SDI), which we tried out on-sky tonight!

Our ASM is a beautiful piece of advanced technology, keeping our wavefronts flat at 1000 times/second (read Kate’s post for why!).  But occasionally the slopes being sent cause the ASM shell to go into its safe position.  It’s either the switch BCU or the BCU 39.  We have a spare switch BCU (see below), but don’t have a spare BCU 39 with us. Hang in there BCUs.

My mom would like to know what a vizcacha is — They are these little rodents, basically a rabbit, squirrel and kangaroo in one package, that live here at LCO and entertain us sunning themselves on the wall or hopping like kangaroos across the rocks!  The official mascot of VisAO is Vizzy the Vizcacha:

And speaking of mascots, the Clio team have been wearing our UA Wildcat pride here at LCO:

Today we were down 50% of our tenured professors and 50% of our Italians.  Phil left yesterday and Simone and Enrico left this morning.  Therefore, I was a little worried because their presence is definitely missed.  Luckily, it was a good night anyway!

We weren’t socked in with high cirrus like we were yesterday, so we were able to keep the loop closed much of the night.  We focused through several of the filters in Clio (Clio has 10 color filters, 2 neutral density filters, and 2 cameras — so it’s quite a lot of modes to commission!  Not to mention the coronagraphs, prism, and non-redundant masks!).

We also got nodding fully functional on Clio.  Nodding is when you move the star to another part of the detector chip.  This is important in the thermal infrared where you have to subtract adjacently-nodded images to subtract the warm sky background.  We nod Clio by nudging the telescope pointing a bit.  This causes the star to also move on the AO wavefront sensor and on the other science camera VisAO.

The AO system can handle the nods, and gets the star back on-axis for VisAO, but it takes a second or two.  During that time, Jared has to deal with bursts of poor image quality on VisAO.  So nodding is working, but now we are working on traffic control.  We are working on getting a smooth operation between the two science cameras that allows Clio to nod without affecting VisAO’s image quality too much.  We are working on taking darks with VisAO’s shutter closed during the bursts of poor image quality.  Watch this video to see how we are dealing with the problem:

 

Here we’re enjoying some good closed loop images:

 

“You can look on either camera for good images!!!” – T.J.

“We’re nodding.  Deal with it.” — Katie

“The loop is back.  Deal with it.” — Alfio

“It’s ballpark super-well focused.” — T.J.

“Your advisor is telling you to take a break???” — T.J. to Jared Re: Laird

“Eat your vegetables at dinner.  They’re good for you.” — Phil (T.J.’s advisor)

“Those are pretty high gains… it’s like we’re doing real AO!” — Laird (1.4 tt and 0.4 ho)

“Look at what Clio is doing to VisAO!  It’s criminal!  See, this is why you never use two science cameras simultaneously!” — Laird

“It’s a frickin’ miracle!” — Laird, commenting on having two science cameras operating simultaneously behind an AO system.

Today we worked more on interaction matrices and calibrations during the day.

In the evening, Phil and T.J. spent some time optimizing and testing Clio.  Clio got to move to the big computer in the Clay control room for the first time (instead of running it off Phil’s laptop).  Here are some pictures of the big event.

 

Jared  is taking the slopes from the wavefront sensor and multiplying them by the reconstructor to determine the phase of the wavefront (including adding back in the high order terms that are above our cutoff frequency).  He writes the residual wavefront error to the VisAO FITS headers.  He also records the gimbal position so we know the position of the star in the image with respect to the center line set by the AO Pyramid.  Jared has calibrated the gimbal position and the wavefront error using the focal plane.  Soon, we will only need the VisAO FITS headers, not the images themselves!

 

Sunrise from this morning:

Jared: I record the wavefront error and position of the star in the FITS headers.
Katie: So what do we need the VisAO CCD for anyway?
Kate: To calibrate the FITS headers!