Blog – Page 165 – Extreme Wavefront Control Lab

Unpacking Day 9: Winds and the W-Unit

The big story at LCO right now is the wind. It is strong enough that it’s hard to walk in a straight line. Here’s a plot of the last 24 hours:

Captura de pantalla 2012-05-25 a las 5.30.24 — One of the telescopes saw a 74 mph gust last night.

It’s still nice and calm in the cleanroom though, and we’re getting lots done. ASM testing continues apace.

Watch those forces. — Marco keeps an eye on the shell. By the way, thanks Marco for helping out with some of the blogging duties around here.

Watch it wiggle — We have started testing our mirror modes - essentially pre-programmed shapes that we use to correct turbulence.

Shiny — A nice shot of the ASM in one piece. Note that the cap is now installed. You can also really appreciate the keyhole here.

We finally mounted the W-Unit on the NAS today. Our wavefront sensor (WFS) is called the W-Unit because the light path makes a W. It is the instrument which actually measures atmospheric turbulence, and it also contains our visible wavelength camera, VisAO.

Watch what you cut. — Laird is removing some cable ties that are still attached after shipping.

After a skype consultation with the W-Unit Master (Enrico Pinna), and with some help from Armando, we hoisted the board onto the X-Y-Z stage and bolted it down.

Nice laser Derek — Here our alignment laser just misses L1 (that's lens 1) right after installing the W-Unit. We made a few adjustments and got the light in the center - but that makes a pretty boring picture.

The boys from Microgate (Mario and Frederico) replaced a power supply in our “minicrate”, which provides high voltage power to our piezo-tip-tilt mirror and camera lens. We had developed a problem where those two components seemed to cross-talk, making a worrisome chatter under certain conditions. It’s fixed. Thanks guys.

Pupilae — Our pyramid WFS pupils, in the 950 dichroic beamsplitter, modulating at 100 Hz. We don't think this is very well aligned, but it is pretty good for a half hours work. And I centered by hand, no auto-center here. That's how I roll.

The side attraction for the last 24 hours has been the VisAO computer. This computer operates the VisAO camera – it saves the data from the CCD and controls focusing and filter selection. Shortly after mounting the VisAO box (containing the computer) on the NAS, the motherboard failed, specifically the hard drive controller. It is a matter of some debate what caused this – it’s been shipped from Tucson to Florence to Las Campanas, and taken apart and put back together many many times over the last 2 years, but mounting could also have stressed the box enough to damage the board inside.

I knew this was going to happen, because motherboards suck. I even carried a spare with me in my luggage because I knew this was going to happen. The brand new spare didn’t boot. Disaster. On a project of this size you might think of a $200 motherboard as a nothin’ part. But as a great man once said “It’s nothing ’til you don’t got one. Then it appears to be everything.”

Poor VisAO — Troubleshooting into the wee hours.

After trying everything else we could think of, we hacked together a solution out of a retired server and the PCI guts of VisAO. She’s limping along. The server used to be called “Vizcacha“, so I think VisAO now has a mascot.

We made it. — This incredibly boring picture means that our stand-in VisAO computer works, and more importantly that the CCD 47 survived shipping. The cap is still on, so this is just a noise frame. Looks like the bayside stages are powered up - see the lines?

We have now turned everything on that we can think of and the only casualty is the motherboard. All of our motors spin or step, our mirror modulates, and our cameras take good data. We’ll do a bunch of rigorous checks over the next few days, but the initial indications are great.

Clay Sunset — This was last night's sunset, as the clouds started blowing in. That's the Clay on the left.

You shall do no astronomy — The sky this morning. The weather has been pretty bad the last day or two.

Hi Marcia — My mom says I should post a picture of myself more often. Here you go mom.

Unpacking day 8: ASM working!

Yes we did! The last night the shell was re-clocked by Armando and Richard that imposed their hands so this morning the shell went again inside the clean tent and was installed by the AO team. The installation procedure took a bit but the TS1 successfully went up and was pulled by the bias magnets against the Reference Body in the standard safe position. After a relaxant trip to Magellan telescope with Laird and Tyson as Chair, Armando fixed the central membrane in the working position and the ASM was ready for slewing tests. No big issues so the system seems really to be on the road to go to the telescope!

Here’s a video of the last part of today’s shell mounting. Skip ahead to about 11:30 for the big moment.

Unpacking Day 7: Clocked Guanaco (shaken, not stirred)

One week in, MagAO shows no signs of slowing down. After starting our day with a hacksaw, and some shaky ground, we prepared the shell for mounting on the ASM reference body and made our first go at it. The shell was clocked slightly, meaning that the magnets don’t quite line up with their holes in the reference body. We have rotated it, and first thing in the morning we’ll retry. In other news: VisAO is back in action, the NAS is shaping up, and we met some of the other residents of LCO.

Bent Pin — Here's the offending bent pin from this morning. We had to use a hacksaw to get it out.

Earthquake — MagAO survived its first Chilean earthquake. It was a small 3.9 mag tremor, but it was close. Lots of people felt it last night. This is an ever-present danger here, and this was a good reminder to 'stow for sea' every night.

Frederico Working on the ASM — Here's Frederico preparing the ASM for shell mounting.

The shell was carefully cleaned before mounting:

Raising the Shell — The shell is slowly raised with a hand crank, with many pairs of eyeballs watching for trouble.

Almost There — Here the shell is getting close. A little bit later we decided that the magnets didn't quite line up with their actuators and so lowered the shell again.

Just in case someone forgets why we're here . . . — At the end of the day, the re-clocked shell is back on the flipping bench waiting to be mounted in the morning.

Tipping the NAS — We mounted our VisAO electronics today. You can see the holes in the side of the box where the cooling system used to be. Here we're using a crane to tip the NAS back to vertical after installing the last box.

It's gettin' hot in here . . . — We paused during tipping to measure the space we have for our cooling sytem. Tyson is helping me test fit the radiator. We now have a plan.

This is how we do it. — For the first time ever, the NAS has all of its electronics.

Tonight’s dinner quote: “That is not a camel.” (Alan Uomoto)

Hi There — We spotted this Guanaco hanging out just below the dorms today, apparently all by itself.

Herd — After lunch Laird and Mario went hunting. Apparently Guanacos follow the same rule as MagAO team members: where there's one, there's 10 or 15. Note the hawk.

Hacksaw

Last night we bent a pin on the handling cart, preventing us from rotating the ASM back to the vertical position for shell mounting. So this morning, the first order of business was to cut the pin out of the cart. Extra fun since this had to take place in the cleanroom.

Problem solved, and we’re right back it.

Unpacking Day 6: Right Side Up

The big accomplishment today was flipping the shell so that the magnets are now facing up. This video, filmed by Juan Gallardo, shows the last step in the flipping procedure:

After flipping, the back of the mirror was inspected. Everything looks great.

Flipped Shell — The shell after flipping.

We also attached the ASM unit to the mount ring, which is how the secondary will be attached to the telescope.

ASM Mounted — The ASM on the mount ring for the first time.

ASM on Cart, Tilted — The ASM unit on the handling cart, being tilted to 90 degrees for testing.

Our heat transfer and fluid mechanics experiments continue:

Our Koi Pond — We added ice to Povilas's fountain today. We have our own chiller for when we're actually on the telescope, so this is just a temporary workaround for the testing we are doing as part of unpacking.

In addition to the main attraction of mirror handling and testing, w-unit and NAS integration work continues. We have tested our X-Y-Z translation stages, installed a new neutral density filter in the VisAO camera, and installed a new gimbal in VisAO. We should actually mount the w-unit in the NAS in the next day or so.

Some interesting quotes from dinner tonight:

“Good news Jared, everybody else is tired, so we can get some work done tonight.” (Laird Close)

“Sometimes you have to hang the stick in front of the jackass.” (Tyson Hare)