Vanessa arrived safely today after boarding 6 planes (but only traveling on 3) to get here. We are happy to see her! She is helping with Clio2 engineering as well as AO operations. We also had 2 of our observers arrive today; their run is in a couple days but they wanted to get up to speed on the system. Unfortunately, we couldn’t show them much at the start of the night, because while closing the loop on the first star, we had a hardware failure that got us pretty worried for a few hours. The ethernet module on our slope computer failed. Luckily, we had a spare, and Jared and Laird put it together without any help from our Italian friends who were all sound asleep in Tuscany.
Two photos of the spare BCU 39 slope computerThe failed ethernet module (top) was swapped out for the spare (bottom)
After they got that fixed (in the mean time, Vanessa and I were working on the CLio computer backup), we got on sky. We had amazing seeing tonight.
I know there’s a reason we picked this site.
And we got some amazing data.
A bright star behind the coronagraph on VisAO at i’ (770 nm) with very high Strehl
We also took some spectral-differential imaging (SDI) data with the Wollaston beamsplitter in to divide the light into the narrow-band and continuum beams. Here is Laird inserting the Wollaston, which he has to go up to the instrument in the telescope to do:
Here is Laird inserting the Wollaston by feel and sound
It was a beautiful night.
The ASM by moonlight. Photo courtesy Prof. Laird M. Close.The Clay telescope by moonlight. Photo courtesy Prof. Laird M. Close.
We’re all quite tired.
The P.I. with his Fanta
But seeing Raphael and Pele dance it up on Xai //na gomasen is quite energizing!
And you can see their dancing much better in this video, I love the Namibian dance style!
T.J., Alycia, and Kate left us yesterday. Vanessa was supposed to be here, but her flight was delayed. So, it was down to Laird, Katie, and Jared to carry on the MagAO mission tonight.
Our day started early. We had to get up before dinner to do some maintenance on our shell wind monitor. This is a little anemometer attached right at the edge of the secondary mirror to tell us if the winds get too high. One flaw with our current device is that it is battery powered and the batteries only last about 10 days. So the crew tipped the telescope over for us, and Laird and Katie climbed up to replace the batteries.
Laird and Katie replacing the batteries on the wind monitor.
After that bit of periodic maintenance was taken care of, we headed back down the hill for our usual breakfast.
We have a nice steak dinner just about every evening — for breakfast.
After that we headed right back up, and closed the loop. Our minimum number of planets detected tonight is 1 (100% confidence). The maximum number is 4, with a most likely value of 2. Stay tuned.
How the AO system looks when it’s running well.
Tonight was a little bit more interesting than usual, since we got to enjoy a total lunar eclipse. We knew we were in for a special night when we saw the moon rise over the Andes on our walk up to the telescope after dinner
The moon looked almost shy.Let the show begin!
With only 3 of us to operate MagAO, Clio2, and VisAO, plus Ernan our telescope operator, we had to watch the eclipse in shifts, leaving one person inside the control room to come holler if something went wrong.
Laird worked hard to get some nice shots of the dark moon.
The eclipse as seen from just outside the Clay control room.Laird might have had too much caffeine before taking this shot. He might also be over-driving tip and tilt.
When the moon is full here, the mountain top is really really bright.
Clay, containing the MagAO system, by the partially eclipsed light of the moon.
MagAO also obtained world-wide coverage of the eclipse. Well-planned, I say.
The departing members of the MagAO team saw the eclipse from the Miami airport this morning.
On our walk up at sunset, the Moon and Sun were 180 degrees apart in the sky. On our walk down at sunrise, they had nearly exactly swapped positions. Mornings here can be stunningly beautiful.
The moon, now opposite the sunrise. Free MagAO sticker to the first person who emails me the name of the pink band on the horizon (hint, the answer is in a blog post from last April).
You might remember that this isn’t the first time we’ve observed an eclipse at LCO.
Have you ever heard that pigeons are the rats of the sky? Well, tonight we were contemplating that binaries are the vermin of the sky. The binaries we are talking about are “stars” that are actually two stars, only they are so close together that they weren’t discovered to be 2 stars by the early astronomy surveys. But when you have AO on a large telescope like we do, you find out that a lot of stars you thought were single are in fact binary. And then you are disappointed if you were looking for something else when you chose to look at that star.
Laird discovered a binary with the pyramid wavefront sensor tonight. The pyramid pupils were lit up diagonally, and he correctly predicted its properties (about an arcsecond separation, about equal brightness) before we even saw it on one of our cameras VisAO or Clio2. Here it is: Laird discovered a binary star with the pyramid wavefront sensor (left) before we even had a chance to look at it in the focal plane with VisAO (right)!
We have been looking at disks around stars recently. Here is a Clio2 image by T.J. of a star that was supposed to have a disk… but instead it was a binary star: A binary imaged with Clio2. The ring around the primary star is the control radius of the AO.
Kate, Alycia, and T.J. are heading down tomorrow, and our mean tiredness is going to go way up. Thanks for all your hard work, guys! Here is the disk team hard at work.
Tonight we got on sky about half an hour earlier than normal, to get some narrow-camera K-band flats, which have proved to be difficult to get enough light. I’ve made a new page with all the Clio2 calibrations, and I’m posting the flats as we get them. They are still not ideal due to an in-focus pupil glow that we think may be related to a slight pupil misalignment. Here we are opening up the dome the previous night: The Clay telescope opening at dusk
And from the inside: The ASM hanging over the Clay primary, from inside the dome, at dusk.
The pyramid pupils taking sky flats. On the left, you can see a pretty cool diffraction pattern around the tip of the pyramid
We miss Alfio, but things have been running pretty smoothly, which is a testament to the amazing software he left for us. The team on Alfio’s last night. From left to right: Kate Follette, Katie Morzinski, Jared Males, Alfio Puglisi, Alycia Weinberger, Laird Close, and T.J. Rodigas.
The Clay and Baade at sunsetAlycia took this picture of Quadritos cereal with braille on the box
Although this post says day 18, we started the 2014A blog on “day 0” (the PI arrived on “day 1”) and it took 2 days to travel here …. so Jared, T.J., and I left our homes 3 weeks ago now, and it’s been 20 days for Laird. In honor of that milestone, here are some pictures from the run that haven’t made it onto the blog yet:
In the first week we were here, Laird put some new filters in the VisAO filter wheel. It took a while because one of the filters wasn’t sized correctly for the slot, so he put a helpful “Stay away” note.The “village” at LCO where we live this month. Down there you can see the dorms and the kitchen.Laird taking a picture of the ASM with his fiducial tape on the cap. He taped the crosshair on pretty much by eye and it worked perfectly!T.J. and I opening up Clio2 in the clean room, back on the first few daysJared is dismantling the earlier part of his PhD project. It was a high-speed shutter he built to do Strehl selection because everyone said visible-light AO wouldn’t work. However, thrillingly, MagAO works great in the visible wavelengths, and we never used the high-speed capabilities of the shutter.Alfio and me after attaching the wind monitor to the ASM with LairdThe small telescope next to the Clay that measures seeing. It is a Differential Image Motion Monitor and is called a DIMM.Panorama around the back side of Clay where the DIMM is. This is where I go hunting for vizzies at dawn.Vizzy resting on the wall, looking out over the LCO villageA wild vizzy at dawn (foreground, lower left), looking out over the smaller telescopes at LCO
And here’s a bird, but not a vermin of the sky: The LCO Whistler at dawn
Here’s a movie Jared took of the LCO whistler, watch/listen to the video and you’ll know why. Note how it tips it’s head back when it whistles!
My brother gave me some mp3’s of him playing some peaceful songs on piano, which has been nice to listen to when I need to focus on reducing data in the control room. One of them is Prelude Op 28-15 “Raindrop” and here’s a version of the song from Youtube:
Tonight we are happy to present you with the first release of the official trailer for the MagAO movie, directed by Alycia Weinberger.
Coming soon to a theatre or scientific journal near you.
We’re still here at LCO, observing star after star, seeing disk after disk, maybe a high contrast close separation point source or two, and we aren’t out of cookies yet. Here’s a few more things going on:
Those “keeners” (Laird’s word) at Baade always beat us on sky. We’re getting faster.The MagAO adaptive secondary mirror catches the last daylight as we open to take flats.
Alycia got a good picture of a cute little vizzy at the ASB which she posted the other day. I saw him or her tonight, and I’m sure this is a new animal that we haven’t been seeing before, maybe a young vizzy. In any case, it’s cute.
A dainty little vizcacha at the clean room.
We are now totally on a night schedule. Here’s Laird, Kate, and T. J., heading down to a late breakfast before bed.
Laird, Kate, and T. J. headed down to breakfast after a long night of MagAO science.
It’s always pretty here, and watching the sunset is our nightly ritual.
Laird, Alycia, and Kate watched the sunset from outside the Clay control room.
Greetings everyone! Long time no blog for me, but I’m happy to be back.
In between running the VisAO camera to give Jared a bit of a break, I’ve been working on quick reductions of the data that we’ve been getting for the past few days. It’s useful to reduce the data at the telescope because these “quick looks” can tell you whether you have what you need or, even better, whether there’s something interesting and unexpected in your data to follow up. We’ve had a bit of both over the past few days as TJ, Jared and I have been running our reduction routines.
Without getting too much into specifics of the targets, I’ll tell you that I had the following problem popping up in my reductions last night
See how you see a bright disk but also a shadow with roughly the same shape? I had to think about it for a bit, but eventually I figured out what my problem was. To explain the solution, I think I should first explain how this type of reduction works.
My pipeline does a kind of data reduction called “Angular Differential Imaging”, which is a neat way to get rid of light from the star in your image and see faint things near the star. Here is an official introduction to the technique, but I’ll explain it very briefly for blog purposes.
For most astronomical observations, you use a rotator to keep the orientation of your object exactly the same as the sky rotates so that the rotator essentially cancels out the rotation of the sky. For ADI imaging, you turn the rotator off and allow your object to rotate with the sky. If you then line up the star in all of your images and median combine them, anything real around the star will have moved around it over the observation, and so it won’t show up in the combination because it won’t be in any given location in more than half of them. Anything fake (well, most things) caused by the optics of the telescope and instrument though, will be in the same place in all the images so it will show up in the median. In other words, you intentionally smear out the real circumstellar structure while keeping the fake structure the same and recover the so-called “Point Spread Function” (PSF) of the star in the median image.
You subtract this PSF then from every individual image to remove the starlight and then rotate them all to compensate for the rotation of the sky so that the orientation of the object is the same in each frame (essentially the same thing that the rotator would have been doing if it were on). This trick usually lets you get rid of starlight very nicely and helps you to pull faint objects like planets out from the data.
It’s trickier though for disks, which is mostly what we’ve been observing for the past few days. If you have a disk that’s symmetric about the star, then allowing the field to rotate doesn’t help you much and the disk shows up in your median-combined PSF. When you subtract the PSF, you subtract most of the disk light too. Bummer.
For this reason, people didn’t use ADI for disk observations for a while, but it turns out that you can make it work in two situations. (1) if your disk has any features (blobs, spiral arms, etc) that aren’t circularly symmetric, then they’ll survive and (b) if your disk is inclined enough (so that it’s not a circle but an oval on the sky) and you allow it to rotate enough so that the disk light appears in fewer than half the images at any given location, then you can still get rid of it for a PSF.
I’d never used this method with our SDI mode before because generally we use the opposite (continuum) channel as a PSF, but we recently pioneered a so-called “ASDI” mode (see Close et al. 2014). The idea there is that you can ADI both SDI images and then subtract them and you essentially get the benefits of two forms of differential imaging.
OK so now to the problem with my new ASDI pipeline. As an object reaches it’s highest point in the sky (transits), it starts to spin faster and faster. We generally get on these objects about an hour before transit when it’s still rotating slowly. Since the rotation starts out slow, then gets fast for a while, then slows down again, the images aren’t equally spread in rotational space. You take a lot of images during the long interval when the object is spinning slowly and not as many while it it spinning quickly. In this case, we left the object right after transit, so there were a bunch of images at approximately the same rotational position, then a few where the object was spinning a lot. If I weight all images equally in the median, disk light ends up in some places in more than half of the images, and I get disk in my PSF and therefore a shadow when I subtract it. So I edited the code to combine images according to rotation angle instead of by sheer number of images. It still has a bug though and I’m sleepy, so you’ll have to see the fix in another blog post. 🙂
Here are some pretty pictures to tide you over.
This band of clouds to the West was just the beginning of our weather problems last night, but it made for a pretty sunset.But no green flash this time
I feel like the pictures we post here can’t really capture how beautiful the 360 degree view of the Andes is, so I’ve been playing with the panorama function on my iphone. It only gives you a 180 degree view, but I think it’s an improvement. Here are a few of my favorites.
We are officially halfway through our run. Although we are super happy to be here and getting great data, we all miss our families and want to thank them for putting up with our long trips here every semester (and for being our most devoted blog followers). Also, thank goodness for Skype/FaceTime. I don’t know how astronomers managed these long runs before video chat!
As I worked on improving my ADI reduction scripts tonight, I kept an ear out for some of Laird and TJ’s usual gems. Here’s a smattering of my favorite quotes from tonight. Everyone gets a little punchy and weird this far into a run, so there are quite a few.
“Technically plants are animals too” -TJ
“I am a marshmallow, your advisor.” -Laird
“I’m just very lucky I have good students” – Laird (yay!)
“I’m the new Alfio” – Laird
“There’s a Clio manual?” – TJ, the Clio operator
“Signal to noise is always lower at home than you think it was at the telescope” – Alycia
“Aww. TJ’s so cute” – Laird, in response to TJ’s optimism about a target
“don’t use your finger to point to the screen” -Laird
“oh sorry you don’t want me touching your screen” -TJ
“no it’s just that your finger is fat” -Laird
“guys, what was your first CD?” – TJ
“my first TAPE was the soundtrack to Miami Vice” -Jared
“Laird probably owned LPs” – Alycia
We also spent a while tonight debating whether the They Might be Giants version of “The Sun is a Mass of Incandescent Gas” was better than the original, but I’m writing the blog post so my opinion is what counts for today.
