Blog – Page 153 – Extreme Wavefront Control Lab

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.

allora — The final result: The new fiducial cross of tape on the CRO (thick orange X in focus in center) is lined up with the cross of string on the W-unit plate (out of focus) lined up with the dark rectangle which is the axis of Laird’s camera.

Step 4: blog it
Done.

three amigos — Alfio, Marco, and Katie depart the Clay telescope, heading down for lunch.

Today we finished the Clio cool-down, and after lunch moved Clio from the Aux and mounted it (her?) on the telescope.

cold as ice — After re-seating a vacuum hose, we got Clio down to 55K

but was there enough suckage? — Katie, Vanessa, and Victor unhooking Clio from its resting place in the Aux.

back together again. — Vanessa admires her handiwork. Clio is back on the telescope, ready to go.

After Clio was on, the grad students kept working.

unless you get sequestered. — This is what life’s like when you’re a NASA Sagan Fellow. Or so I’m told.

After dinner, we proceeded with aligning the system for CRO tests.

The thick spider is actually the CRO stage cables. — An almost round (opinions vary) pupil using our alignment laser. This is light reflected off the secondary, into the CRO, and back off the secondary.

A herd of burros came to the watering hole close to the lodge today.

Sticking close to mommy. — A baby burro.

is it a real boy? — The south end of a north bound burro.

We missed sunset tonight, but we never miss a Vizzy photo-op.

she has adopted an air of patient tolerance with her paparazzi. — A perfect Vizcacha profile.

does it look like this up north? — A moon shot by Vanessa.

Quotes:
Laird: “If we don’t get good suckage, it’s not going to work.”

Laird: “It’s like yoga”
Povilas: “It’s like hot yoga!”

Laird: “I often get a little confused about what’s hot and what’s not.”

Vanessa: “I only took 4 pictures today. I wasn’t very productive” (the blog is our #1 priority)

Comm2 Day 3: NAS and CRO day

Today we installed the NAS (the metal ring that mounts to the telescope and holds all our instruments) and the CRO (the calibration return optic, for internal alignment and calibration). We also said goodbye to Tyson — thanks for everything! It was a long day and I’m tired so this will have to be quick, even though lots of fun stuff happened.

First the NAS was installed.

optics is a French sport — Povilas collimating the telescope before the NAS was put on.

Mission Impossible? — Here comes the NAS, up from the basement of the dome.

Then we needed to create a new fiducial for the CRO so that we could align our internal light source along the optical axis. It was a fun exercise by me, Marco, Alfio, and Vanessa, and it reminded me of the Inquiry labs I did in the Professional Development Program when I was a grad student.

Great job, everyone! — Coming up with a procedure and then implementing it to create a new alignment fiducial on the back of the CRO.

Yay! — The final result of the new fiducial on the CRO.

was pretty fun — Laird and I putting some more tape on the CRO fiducial.

thanks — Juan and Laird going up in the scissor lift to install the CRO (that I’m handing to Laird)

Quotes:
“Here, try it — shine a light in your eye!” — Laird

“I know I don’t like it just from looking at it.” — Laird

Laird: “This is a little unexpected.”
Povilas: “If it’s unexpected, that’s your fault.”

Comm2 Day 2: The ASM lives

Today we said goodbye to Alan. Thanks for all your help getting us up and running!

Laird shows off his Arizona pride. — Marco, Katie, Jared, Alan, Laird, Tyson, and Vanessa. (not pictured: Alfio)

Even with Alan departing, the mountain is full to the brim with personnel, and we need all the space we can muster for the President of Carnegie’s visit later this week.

Doubling up on rooms, just like the good ol' college days. — Every available dorm space has been claimed, and then some.

Today the crew installed the ASM. First they had to remove the other secondary mirror which was installed on the telescope, which took several hours. By mid-afternoon they were ready to install our secondary mirror (the ASM).

First, we moved the ASM into place, and cleared the area around the telescope.

Off to the races! — We rolled the mirror, still covered in a protective layer of plastic, into the telescope chamber. The crew had to move some scissor lifts out of the way, so we had a place to put the mirror and cart safely away from the telescope.

In order to install the secondary mirror, it must be lifted by crane out of its cart and across the telescope chamber, over to the telescope structure. This is a nerve-wracking process, so the crew proceeds slowly and systematically. Thanks for a flawless install, everyone!

Because the crew cannot easily access the telescope when it is pointed straight up (“zenith-pointing”), the whole telescope structure is tipped down (“horizon-pointing”). When the telescope is horizon-pointing, the top of the telescope structure (where the ASM is mounted), lines up with a catwalk which extends around the dome.

As the mirror was lifted from its cart, Laird held his breath. — The mirror was lifted from its cart with a crane which is attached to the telescope dome itself (yellow structure in the bottom right image). The crane can move toward or away from the dome wall, but can’t move sideways, so the entire dome is rotated to bring it over to the telescope.

After dinner, Laird and Marco connected the control and cooling lines to the ASM. We use a liquid cooling system to keep the mirror components at a safe operating temperature, so before powering on the ASM, we checked for leaks (we were A-OK). Then, Marco showed Katie how to power on and configure the ASM.

Pondering the ASM — Marco and Katie work through the ASM startup.

Amazingly, the ASM started up on the first try! We were all pleasantly surprised, since the system had been sitting in storage for several months. In fact, the time from start to finish of the entire installation and startup process was only 7hr, including a leisurely dinner break.

It's alive! — The software control for the ASM after a successful startup. The window on the right shows a real time view of the postions and currents of each actuator in the mirror. The left window shows the status (the three green boxes at the top are good!)

The ASM wake-up wasn’t the only thing going on around the mountain today.

Jared showed off his thesis project. We’ll be mounting the whole assembly tomorrow, so check back in to hear all about it!

Check out that swag. — Jared shows off his thesis project (hint: not the crate cover).

We continued to cool and test Clio:

Ice, ice, baby. — We attached a vacuum pump to one of Clio’s nitrogen reservoirs (via the clear tube coming out the top). By lowering the pressure in the reservoir, we can solidify the nitrogen. This serves dual purposes: it further cools the detector, increasing its sensitivity; it also keeps liquid nitrogen from spilling out of the reservoir when we turn Clio upside down.

And Alfio helped debug the wavefront sensor control software:

Time for reinforcements. — Alfio briefly takes over the command center.

Lest you think it’s all work and no play on the mountain, we squeezed in a few photo-ops:

Another pretty sunset from the catwalk:

Or just a bad white balance? — A yellow-green flash, perhaps?

Along with an equally pretty moonrise:

Miss Vis made an appearance:

Check out those whiskers. — Miss Vis lazes in the shade.

And I took a couple pictures of Clay and Baade by moonlight:

Is it our turn yet? — Clay by moonlight.

Just starting to slew to the next target. — And Baade too. Alpha Cen is at the very edge of the image in the upper right.

Quotes:
“Yay!” — Jared over the walkie talkie after Laird informed him the ASM was alive and well. (There was much rejoicing all around).
“You and Jared could power an approximately-infinite improbability drive.” — Vanessa’s parents after learning about the geographical coincidences mentioned in the previous blog post.

Comm2 Day 1: The ASM heads up the hill

Today was the first full day for our expanded team. After a long 2 days of travel, we got a lot of good sleeping and working accomplished. Oh, and Laird’s suitcase arrived — it’s nice to have toiletries!

anchor — The expanded team looked well-rested at lunch (Marco, Alfio, Vanessa, Katie, Laird, Jared’s sweatshirt).

Today Marco and Alfio checked that the ASM cabinet powered up and that the system looked OK.

Yesterday the spic-and-span primary mirror was re-installed in Clay, and last night our telescope was collimated:

Not our secondary! — The Clay telescope being collimated (last night at sunset)

Today we moved the ASM from the clean room up to the Auxiliary building at the top of the mountain.

Laird claims he is a better sailor than Jared. — We prepped the ASM by turning to face vertically — a stronger position while in motion (it is stored face down — a safer position in case anything strikes it), inspected the mirror surface, and tied it securely to prevent bounces or shocks. In the lower left, Laird is using his sailor skills to show Vanessa and me how to tie a bowline knot. In the lower right, I am trying to get a close-up shot of the slot, my favorite fiducial. The white arcs in the lollipop part of the slot are capacitors for the sensors.

Photo by Paula -- came out very well! -- Vanessa's camera — We paused to take a group picture while the truck was being prepared (Alfio, Vanessa, Katie, Laird, Marco)

I think we have a very similar shot from Comm1, except this time we turned it 180 to face away from the sun. — Here the ASM is being loaded on to the truck. Very carefully.

Vanessa takes amazing pictures. — Strapping the ASM down to the truck.

Slow enough for a PI to walk beside — Here the truck is driving the ASM very slowly up the mountain.

Carefully. — Finally, the ASM is rolled safely into the Aux.

Going to the telescope tomorrow — The final result.

This morning Gabriel began cooling Clio with liquid nitrogen:

Gaseous nitrogen — Liquid nitrogen being pumped from the big tank into the little tank… and then from the little tank into Clio

Vanessa got to work monitoring the instrument and updating its software. Here she is connecting the motors last night:

A happy grad student is a good grad student — Vanessa connecting some Clio motors

Gabriel from the day crew filled Clio during the day, and Vanessa and I filled it after dinner, in order to speed it on its way down to 77 Kelvin:

Until we ran out of LN. — Vanessa and I cooling down Clio.

Here is a video:

Laird, Jared, and Vanessa cleaned the optics in the W-unit and Clio dichroic with soft lens brushes today:

Don't sneeze, Vanessa — Laird and Vanessa inspect the Clio dichroic. Laird is holding a soft-bristle lens brush used to wipe off dust.

This morning Jared saw a guanaco, looking quintessentially Andes:

Cutie — A guanaco in its natural habitat (left) and zoomed-in (right)

Vanessa and Jared saw a bird in the Aux:

Mellon — A bird perched on top of the shelves by the propped-open door to the Aux.

Then this afternoon, Jared and I saw two burros, very appropriately for Palm Sunday:

Harking back to his farm boy childhood in Pullman, WA and Brookings, SD — On the left, you can see two burros in the foreground, and the 100″ telescope in the background. On the right, Jared is making big loud sounds to “get their ears up”.

Quotes:
“To the nunnery!” –Tyson, heading out after the morning meeting.
“You get them in your mouth!” –Laird, talking about moths at MMT (fortunately, not a problem here!).
“It’s ballpark super-well cooled down.” –Vanessa, reading the Clio temperature gauge.

Comm2 Day 0: Arrivals

The MagAO team got a lot bigger today. Laird, Katie, Alfio, Marco, and Vanessa arrived at LCO today. Marco took some pictures after they all met up in Santiago.