We’re on the third and final night of the intermission between the MagAO-X on-sky nights. Tomorrow (which is now today), we’ll spin the tertiary around to feed starlight down the waiting maw of MagAO-X for the third time.
In the meantime, we’ve continued to work out bugs, close and refine the loop on our internal source, and argue about future improvements to be made on the instrument. This mostly just looks like fatigued astronomers and grad students frowning at their laptops, which has been covered in some detail in the last two blog posts. Instead, I present a modest selection of images taken around LCO in the last 24 hours:
We managed to pull ourselves out of bed before dinner to run (well, drive) up to the Clay for a quick group photo in front of the instrument.
Today’s song is “Hang on Little Tomato” by Pink Martini.
Today marked MagAO-X’s last day in the clean room at the halfway house and its first night in the Magellan Clay dome.
The day started with a lift (now almost mundane) of the optics table off its legs and onto the transport cart. We pushed it out the clean room doors and onto the back of the waiting Isuzu flatbed for its journey of a few hundred feet up to the Clay.
A few minutes later, the instrument was unloaded at the Clay and staged for its eventual afternoon trip up the elevator to the Nasmyth. In the meantime, the legs were put in position and the electronics found itself on the way up the hill shortly thereafter.
The goats were suspiciously absent today, but Gary materialized in the afternoon to satiate our wildlife-sightseeing needs. After a short break, the instrument table was elevated up into the Clay, craned into the air, and rejoined to its legs.
Olivier arrived at LCO just in time for dinner (as well as a cup of coffee [or several?]). After a tour of the facility, a quick spin on the Nasmyth, and a demonstration of cart racing by Laird, the team stopped to watch the sunset, as is tradition.
With one day more to first light, the song of the day must of course be “One Day More” from Les Misérables:
This morning, Laird and Alex rotated the K-mirror to a more optimal position and re-aligned the rest of the optical train. I switched out a board in an ALPAO driver to one that lets us power the NCPC (non-common-path-corrector) DM remotely, which saves us many hypothetical trips to and from the Nasmyth platform. Jared did…well, a lot of everything.
One tool that has proven useful in the alignment process is an “F”- and “X”-shaped pattern on the 2K deformable mirror (previously featured here), which we can view in high resolution on our LOWFS (low-order wavefront sensing) camera.
After Alex and Laird were happy with the alignment, I drove out (most of?) the remaining system aberrations with the “eye doctor” script, which attempts to find the combination of Zernike modes on the deformable mirrors that maximizes our Strehl.
Reinforcements in the form of Joseph Long arrived this afternoon, although fumigation delayed his luggage in Santiago and left him (temporarily, we hope) dispossessed of his worldly goods (and a few supplies for MagAO-X). The MagAO-C team joined us after dinner for a tour of MagAO-X.
After the tour completed and the crowds dispersed, Alex and Laird reinstalled the panels, shielding the instrument from prying eyes (and unwanted particles—of both the massive and massless variety). Jared installed the blower (the large white tube entering the instrument table from the left) to supply the optics with a soothing breeze.
After spying a guanaco in the far distance earlier in the week, I finally encountered two up close yesterday. They were surprisingly…pungent.
As always, we stopped to watch the sunset.
For the song of the day, I present “Stairway to the Stars” by the Queen of Jazz herself, Ella Fitzgerald.
Unpacking Day 2 marks the 3rd day of MagAO-X unpacking activities, which only makes sense if you’re a computer scientist or you just try not to think about it too much.
Alex and Laird began the day by removing the teflon bars that had been installed in front of particularly expensive optics for protection during shipping.
Meanwhile, Jared pressure-tested the electronics rack coolant system while I set up the AO Operator Computer.
We filled the instrument coolant lines with glycol and hooked the table to air, giving MagAO-X its first breath and drink at LCO.
After passing its pressure test, the electronics rack coolant system joined in on the activities. Things got a little out of hand when Jared fashioned a makeshift bong and started passing out mixed drinks (glycol and distilled water — not recommended for human consumption).
And, most importantly, the goats made another appearance.
I present the MagAO-X song of the day: “Always Something There to Remind Me” by Naked Eyes (related to the most recent MagAO-C song by its year of release—a tenuous but legal connection) .
Late last week, after painstakingly recabling and aligning the BMC 2K following its relocation to the MagAO-X instrument, we closed the loop at 3.6kHz with 2040 actuators. See Jared’s video below:
What exactly are we looking at in this video?
On the far left is the image from our pyramid wavefront sensor. It’s tricky to interpret, but the four pupil images are a bit (but not exactly) like a 2-axis knife-edge test, with the key difference that aberrant rays are refracted into the different pupil images rather than simply blocked or passed. Through the magic of linear algebra (and lots of calibration), each frame from the wavefront sensor is converted into a map of voltages to apply to the DM to cancel this wavefront error.
The DM commands can be found along the bottom row of windows in the video. It’s split across multiple channels, but the important one is the image on the far right: each pixel is a command we’re sending to an individual actuator on the DM. With the loop open, we’re just creating simulated atmospheric turbulence. With the loop closed, it’s the same simulated turbulence plus the correction computed from the wavefront sensor.
And, finally, on the upper right is the “science” PSF, doing its thing. (That last image on the desktop—the pixelated one in the top middle—is the command sent to the ALPAO DM, but it’s not doing anything here other than holding a flat shape.)
Before we could close the loop, the 2K had to be aligned, which isn’t a trivial task when you’ve just dropped it into the middle of a rather complicated optical system and expect the beam to be centered on the DM to better than one actuator (which have a pitch of 400 microns). Enter Laird and Alex, experts on all things alignment. To aid in their efforts, we placed a pattern on the DM that could be seen both on the wavefront sensor and by eye in the beam reflected by the DM.
This isn’t the first time we’ve closed the loop on MagAO-X. A month ago, we closed the loop on the low-order ALPAO DM-97 (the woofer). We have video evidence of that too:
And finally, to procrastinate studying for finals a few moments more, here’s my half-micron (peak to valley) entry into the ongoing MagAO-X logo contest, imprinted on the 2K and measured on our Zygo interferometer: