Today was the 365th day I’ve spent at Las Campanas Observatory. You only have to go back to May 18th, 2012 to find the first. So 16.7% of my life has been on this mountain over the last 6 years.
It was an interesting 1-year day too. Of course, it was Empanada Sunday. According to my records, my average length of stay has ben 21 days, so ~3 Empanada Sunday’s per visit X 17 visits = 51 total Empanada Sundays in my life so far. Here’s what just one looks like:
It takes a lot of empanadas to feed the GTM Proto3 phasing team, and the MagAO crew.
My longest stay here has been 44 days. That was what I call the “Death Run”. Late May and early June, telescope open for 13+ hr a night, horrific winds, 5 weeks straight of observing. When Katie reminisces (not fondly) about it, she says “you could sleep, eat, or shower. Pick 1.” Well, to commemorate that on mine and LCO’s 1 year anniversary, here’s a picture from the wind gauge tonight:
Not the highest tonight. I saw 46 a few times.
We managed to open a couple of times. But when we did it was pretty crappy
This is a crappy weather page. The trifecta: high winds, high seeing, high humidity.
I’m pretty sure this is fake news (probably a spurious measurement while Baade closed), but it captures how bad tonight has been.
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Read Below to find out what this odd looking video is!
Yesterday we mounted the SAO’s Giant Magellan Telescope (GMT) dispersed fringe sensor prototype (Proto3 — Brian McLeod’s 3rd version — it keeps getting better). This is a complex set of infrared cameras and optics that mimic 3 of the GMT primary mirrors boundaries. It is basically a 2 slit experiment that interferes light (to make “fringes”) from the edge of each primary (where they almost touch) of the GMT. In this manner we hope to measure if one primary is slightly higher (out of phase in piston) with respect to the other primary — this will be a critical measurement to enable a diffraction-limited GMT in the future.
So that means we turned Magellan/MagAO into just 3 pairs of slits and look at the interference between the pairs. See photo below of the Magellan pupil with these 3 slits pairs superimposed over it.
The Proto 3 pupil — basically 3 double slits
The fringes produced by the 2 slits are then dispersed in the vertical direction — in this way it can capture/measure up to ~40 microns of piston between GMT segments.
In the photo below you can see the 1.1-1.3 micron (infrared) spectra of the fringes, here MagAO was locked on 300 modes.
Fringes from Proto3 ! The fringes are dispersed from red to blue (in the J band) from top to bottom — if there was piston between the slits the fringes would twist and look like a “barber-pole”.
Jan Kansky took this great photo of Proto3 (the box above Derek) mounted on the back of the NAS
Derek Kopon and Proto3
The main test of the system is to understand the “fringe behavior” when Proto 3 looks far away from the guide star that MagAO is correcting. Below we show a video of what the fringes look like when the fringes come from a star that is 6 arcminutes away from the guide star.
Movie of the fringes 6 arcminutes off axis from MagAO’s guide star
So in keeping with tonight’s theme — here is a Fringe song about the TV show of the same name:
Here is a different version:
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