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!
Runa represents 50% of our remaining Italians. He keeps the ASM in good working condition, while Alfio keeps the loop closed.
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:
Laird, Jared, and T.J. admire the closed loop images and real-time WFE and Strehl calculation on VisAO
“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.
Katie and Laird take a picture for their various mothers.
The unofficial battle cry of the MagAO project over the last few days has been “More Cowbell!” as we try to get a high-order basis set that keeps our actuators happy.
Will this basis set work? Stay tuned.
To get the truly amazing image quality that our system is capable of, we need to find a set of shapes for our mirror that is stable on sky. We aren’t there yet, but we also need to test what we have on real stars to make sure we are on the right track. So we went on sky again tonight, but first we had to pull the CRO.
Laird removing the CRO optic from the CRO truss. It's very precisely aligned, so it's a slow and careful process.Laird and Povilas mounting the plexiglass cover that protects the shell when we remove the CRO truss. Sometimes putting the cover on is the most dangerous part.The night started with an in-the-dark checkup on the Clio electronics. Here Katie is opening the rack.Ya-Lin and T.J. hard at work on Clio astronomy -- 100 hoursThe control room of Clay - actually doing astronomy.Since our main goal right now is to test the AO system, we can't predict where we're going to be pointing and what we'll be ready to do, so picking targets is a full time job. Here Katie and Kate are combing the digitial sky for interesting places to look.We're getting our acquisition sequence down. The telescope operator first finds the star, and uses Alan and Tyson's guider to setup the telescope. Then we do a slight offset to put the star on the pyramid. To do this we first use Clio's wide field of view to get the star onto VisAO, then we use VisAO to guide the last few arcseconds. Here Katie is selecting our next target, and Povilas is supervising the telescope setup.
Kate found us a nice quadruple system to check our closed loop image quality:
Closed loop image of a quadruple stellar system on VisAO. We resolved the 4th component at only 0.1 arcsecond separation.
Simone and Enrico are leaving this morning. Right before he left, Simone showed me this. Maybe it contains the answer to the riddle: “how do you simultaneously minimize force and maximize rejection?”
The answer.
“I got a fever, and the only prescription is more cowbell.” – Laird Close
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.
T.J. is impressed by all the real estateOptimizing the systemT.J., Phil, and Jared working on their respective science camerasMeanwhile, I was running the AO loop
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!
The VisAO quick-look guiJared's VisAO software reports the AO loop status, the wavefront error, and the Strehl in real timeThe VisAO FITS headers record the WFE and the gimbal position, so in principle you can reconstruct the image plane without needing the actual FITS image
Sunrise from this morning:
Sunrise from this/yesterday morning.Moonrise from this evening.
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!
Greetings MagAO blog followers! Tonight, I’m giving Jared and Katie a well-deserved night off from the blogosphere. Don’t worry – they’re still hard at work on the system, and continuing to collect pithy quotes and hilarious anecdotes for your entertainment.
I’ll start with a recap of yesterday, since I neglected to send the “good pictures” to Jared before he posted the blog entry. As you may recall, we had the first real starlight pass through our system last night! Here are a couple of pictures of the action.
Even though they look disappointed, those are actually triumphant smirks on the faces of MagAO PI Laird and AO guru Alfio. Jared contemplating real starlight on his VisAO cameraFirst light night at Clay. Thanks Yuri for the awesome picture!This one is actually from several days ago. Shh.
After we successfully closed the loop on-sky and the day crew left for some much needed rest, the night crew continued to push the system. As we ramped up to 50 modes, we were thwarted repeatedly by a ring of actuators where very high forces were building up and breaking our control loop. While we were mulling on that, we managed to do some important science calibrations. Specifically, we figured out which way was up. No really.
With all of the rotations and reflections of a complex optical system, “up” is non-trivial, so you have to do some testing to figure out how north, south, east and west on the sky map to your camera output. We also figured out the “plate scale” of our instruments, which just means that we looked at a binary star system of known separation and calculated how big each pixel on our detectors is when it’s mapped onto the sky. We will have to do this more precisely in a few days, but were relieved to get the answer we were expecting. No unit conversion errors here!
Before going to bed, we also took some on-sky science data for the science team to practice with. More on this later.
This is a bird. Jared made me take a picture of it because he believes that this is the culprit who has been pooping on the optics. I'm pretty sure that this is just a random bird, but I indulged him anyway. I insert it here to distract the reader from the long text of my blog entry, so that my advisor won't comment derisively on my liberal arts education tomorrow.
Today the day crew put the CRO back on the telescope to continue their calibration work. They quickly discovered that our actuator ring problem was due to the method used to “slave” the inner rings of unilluminated actuators. Now the system is running well at 400 modes without breaking, and the Italians have gone to bed to rest their brains in preparation for a ramp up to more modes tomorrow. The night crew is hard at work continuing their calibrations.
It’s not a MagAO blog post without a wildlife reference, so I should mention that on my hike up the mountain to the telescope this afternoon, I encountered Vizzy and a friend hanging out under the eaves of the ASB roof. Now, when I first came to Chile as an undergrad 10 years ago, I was told of these mythical creatures known as “vischachas” that were part kangaroo, part bunny, part squirrel. Memories of my dad having me look for jackelopes on ski lifts when I was a kid left me (appropriately) skeptical, so I was surprised to come face-to-face with two real live vischachas today. I watched them for several minutes to make sure that they were not stuffed and part of an elaborate prank. I have yet to see them hop like a kangaroo, so stay tuned for future investigations into the vischacha phenomenon. In the meantime, I hope that the following picture is more convincing than your typical sighting of Nessy or Big Foot.
I snuck up on Vizzy from the backside of the ASB and waited until I saw him move his whiskers.Katie, Alan, Phil, Jared and Ya-Lin posing with the moon on the Magellan balcony. Clay and Baade at sunset. I don't have a wide angle lens, so this is the best I could do to give you the whole picture.
Now on to my alterior motive for posting today. I’d like to take this opportunity to answer the question, put to me directly by both my husband and my father after reading the blog, “So… it sounds like things are going great over there…. but why are YOU there again?”
It’s a fair question. What ARE all the rest of us doing? You’ll find evidence of our existence in the footnotes of previous blog posts (“so and so arrived today”) and in the backgrounds of pictures, but what are we actually doing?
No we weren’t eaten by Cart-Zilla before we could get any real work done! No, we’re not twiddling our thumbs, sleeping all day, watching movies, or leaving our husbands to fend for themselves for weeks on end for no good reason at all. We’re here for science.
I asked the newest member of the MagAO team to demonstrate:
Ya-Lin doing SCIENCE!
There are a lot of practical problems to be solved before we start collecting science data, and that’s what the rest of us have been working on. We’re making sure that all of the file information that we need is written correctly and automatically when we take data, that we know how to tell the telescope where to point, that we have lots of options for good scientifically-interesting things to point at, that we understand how our instruments are performing and, perhaps most importantly, that we know how to process the data coming out of the system so that we can actually do science when the time comes. For example, a typical VisAO data set might contain 10,000 images. Processing such a large number of images at once requires some careful planning, so we’ve been busy testing different methods to try and speed up the process. So that’s what the rest of us quiet M-star types are doing here while the O and B engineering superstars are burning brightly on the blog.
Warning: I’m about to get deep here. Perhaps it will even make you forget my corny spectral type joke.
In conclusion, I’d like to take a moment to appreciate the complex mechanical, software and optical engineering that goes into a system like MagAO. Even after being involved in this project for 4 years, I’m not sure that I fully appreciated the complexity until I got here. The MagAO system has to control many components to micron precision all while the telescope is tracking, the mirror is deforming, and control programs are running on four or more separate computers. All of these pieces have to speak coherently to one another, and do so seamlessly so that we observers can do our science. Everyone knows that science is sexy, but as I’m discovering, engineering can be sexy too!
Therefore, I leave you to contemplate Cart-Zilla, an engineering marvel.
Laird describes this contraption as the result of "Engineers Gone Wild". Presumably there was less toplessness involved than in other iterations of the "Gone Wild" franchise.
