MagAO 2018A Day 17: The Wrong End of a Telescope

Proto3 has been detached from MagAO, and now MagAO is fully put away. Since this (northern hemisphere) fall will extremely busy with work on MagAO-X, it’ll be a whole year before we’re back here.

My check list for today:

  • Switch back to a day schedule all in one go
  • Take the last final exam for my first year of graduate school
  • Remove a 1000+ lb piece of scientific equipment from the top of a three-story tall machine

I’m happy to report that I accomplished all three, though it may be more accurate to say that I was a minor contributor to the last task. It takes a whole crew to remove the adaptive secondary mirror from the Magellan Clay telescope, and my main contribution was to help Laird keep all the various power, data, and coolant lines from getting away during the disconnect process. (Pink zip ties are the astronomer’s best friend.)

Since I was not operating a crane or lifting 80 lb load spreader bars by hand, I was able to document the process. Enjoy!

It's fun to stay at the Ell Cee Oh, yay!

The author, looking like a member of The Village People, prior to ASM decabling.

I felt like one of the monkeys my sister studies, climbing up there.

To swap secondary mirrors, the telescope points parallel to the ground. There’s a crane that rotates as part of the dome which can very gently lift the ASM out and transfer it to a storage cart while the static secondary is in place.

Tomorrow, we leave LCO for La Serena (and Santiago and Dallas and Tucson, hopefully without issue). We’ll be back next year!

Last, but not least, here’s a song of the day about looking through the wrong end of a telescope.

(Lucius – Turn it Around)

And here’s a cover version I dug up by someone with cool hair:

(Kaela Sinclair – Turn it Around (Lucius cover))

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MagAO 2018A Day 16: Day 365

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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MagAO 2018A Day 15: Fringe Science

Read Below to find out what this odd looking video is!

Hi All,

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

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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