Today, for the first time, all of the MagAO system was on the same continent, and even in the same building. On top of that, after a 50 hour odyssey Laird, Victor, and Jared arrived at LCO to begin unpacking. MagAO is officially at Magellan! Here are some pictures from today.
The MagAO ASM arrives at LCOThe conductor celebrates the end of a *slow* drive up the mountain.
Meanwhile, somewhere between Tucson and La Serena:
Victor and Jared pose after defeating Chilean customs with way too many parts of MagAO in our luggage.
And finally at the top of the mountain:
We witnessed a blast for the GMT.Here we see the backup transport system, standing by outside our dorm rooms just in case.Our future home, the Clay Telescope, is the one at left opening at sunset.Venus over LCO. By the way, the stars are weird down here.Laird celebrates the fact that none of the drop-n-tells tripped on the outer box. This means that the shell was handled very carefully on its trip from Italy.Our electronics waiting to be unpacked.Victor and Alan unbolting the top of the outer box.Jared expresses his opinion about something. Ask me later - it probably doesn't matter. Update 4 days later: it didn't matter.We only tripped 2 of 3 5g drop-n-tells on the inner box. This is a great sign that our delicate shell was treated well on its journey.Here we're moving the inner box. Jared is operating the crane, and Laird is guiding the load. Victor guides the inner box and its delicate contents down. The foam behind him was on top of the inner box.
At the end of our first day the inner box was safely stowed in the clean room, and we have started unpacking our electronics. A big first day.
The NAS and all the W-unit and VisAO electronics landed in Chile early on Tuesday morning. The first part of MagAO has now arrived in Chile!
Our other big news is that the ASM – meaning the thin shell itself and the ‘unit’, which means the reference body and attached electronics – has left Arcetri and is on the way to the airport in Firenze. This process will take a few days for customs etc. The pictures below, courtesy of Armando Riccardi, show the final stages of packing the ASM and loading it on a truck.
Our mirror is swinging through the air! This is the "small box", containing the 85cm wide by 1.5mm thick thin shell of our adaptive secondary mirror.The "large box" being loaded on to the truck. The "small box", shown above, is packed inside this box. This system is carefully designed to protect our delicate mirror during the flight.Here we see the reference body and electronics being readied for packing in their shipping box.
After our pre-ship review, we had a few things to fix – the only difficult one was a misbehaving actuator in the ASM. These have all been dealt with, and after a final review by the director we today received permission to ship the Magellan AO system to Chile.
LCO here we come!
Some packing pictures courtesy of Carmelo Arcidiacono:
Carmelo measuring the height of the packing box, resourcefully with his inseam.The W-Unit (WFS and VisAO Camera) in its wooden shipping crate. The gray crates behind contain the system electronics.The NAS being lowered into its shipping crate.The NAS safely in its box.Time to put the lid on. How many Watts RMS?
The Magellan AO VisAO camera includes a novel system for performing “frame selection”, which is the technique of using only periods of good seeing and/or AO correction in the final science image. Traditional “lucky imaging” does this by reading short exposures and selecting in post processing. In our system, we use measurements of Strehl ratio in real time and open and close the shutter based on those measurements. This video shows our shutter working with the AO loop closed in the Solar tower in Arcetri, Italy. It was taken during the week after our pre-ship review.
The Strehl time series is derived from our custom wavefront reconstructor (calculations are done on a GPU). During this testing the shutter decisions were based only on the most recent Strehl measurement, meaning that we did not use any predictive algorithms. Note the fleeting moments of a clear Airy pattern as the shutter finds the highest peaks in the Strehl ratio time series.
The real question is: does it do any good? We’re still analyzing all the data we took, but for now this demonstration is an important step showing that our telemetry and hardware systems can do real-time frame selection.
This video demonstrates the MagAO high-level software GUIs used to acquire the star, set up the AO system, and close the loop. The entire process takes about ~3-4 min. at this time.
(Filmed by Alfio, narrated by Laird, cameo by Katie operating the VisAO camera)
Description:
After the telescope slews to a new target, the guider will acquire the star to within 4” on the Technical Viewer (CCD 47 in AO acquisition mode; otherwise CCD 47 is the VisAO array). Next, the MagAO Command GUI controls the AO system and is operated as follows:
PresetVisAO — Transforms the CCD 47 from its role as the Science Camera (VisAO) to its role as the AO acquisition camera (Technical Viewer).
Takes control of the CCD 47, gimbal, and filter-wheel 2 and 3
Opens up filter-wheel 3 (coronagraph stops and SDI narrow-band filters)
Centers the gimbal
PresetAO — Configures the board for acquisition, and uses the estimated NGS magnitude in order to determine the AO system parameters (frame rate, modulation, binning).
Start with a guess of the NGS mag (entered by hand, or will be read in from the starlist provided by the astronomer) — required for appropriate speed and binning to get good SNR photometry. These settings are read from a lookup table
Opens up filter-wheel 2 (SDSS r’, i’, z’, and 950 long-pass filters)
Moves gimbal to point off axis to take CCD 47 darks
Sets binning and framerate on both CCD 39 and CCD 47 based on the estimated NGS magnitude.
Places the beamsplitter wheel in the dark position for CCD 39 darks
Once darks are taken, re-centers the gimbal
Wait for all movements to finish (stages, filterwheels, etc)
AcquireRef — Aligns the guide star onto the pyramid. Metric is position of the star on the Technical Viewer (CCD 47).
Finds star on Technical Viewer
Finds offset from pre-determined home position (green cross)
Moves X,Y Bayside stages (entire W-unit) to remove offset
The above steps are performed iteratively until the star is on the green cross to within 0.2 mm of stage movement
Set filter-wheels for AO. Filter-wheel 1 (beam splitter) will be placed in the correct position based on star magnitude.
AutoCenter — Fine-tuning of the alignment onto the tip of the pyramid. Metric is pupil illumination on WFS camera (CCD 39).
Button on the CCD 39 image viewer
Moves X,Y Bayside stages to even out the illumination (i.e. zero out tip and tilt)
Iterative process; Final precision is ~few microns
StartAO — Closes the loop.
First closes the loop with only 10 low-order modes to center up the camera lens (the camera lens loop aligns the pupil images to keep the illuminated pixels constant to 1/10th pixel)
You can next load artifical turbulence in the lab to simulate on-sky AO
Sets the frame rate, modulation, and binning determined in PresetAO
Closes the loop with all modes (400 modes in bin 1; 120 modes in bin 2; 50 modes in bin 3; 28 modes in bin 4) and low gain
AutoGain starts and iteratively guesses-and-checks the gain for each mode grouping (low, mid, and high) that minimizes the slope RMS
Finally, we have an optimized closed loop. The instrument can be turned over to the astronomer for diffraction-limited data acquisition
