Climbing the Stairs

Stairs
The five flights of stairs needed to climb the Keck 2 Nasmyth Deck

Wait! What is broken?!?

The elevator.

It has been broken for two days. The contractor is here to fix it, but this is the day Olivier and I need to get a job done in AO. It would have to be the Keck 2 elevator, not the Keck 1 elevator. Which telescope are we working in today? Keck 2 of course.

This will mean climbing the stairs to the Nasmyth deck, all five flights of stairs. Five flights does not sound too bad, until you remember that the bottom of these particular stairs start at 13,600ft above sea level. Climbing these stairs is guaranteed to get your heart pumping and remind you of the consequences of every one of those 13,600ft.

The job? Re-installing one of the mirrors in the rotator that was re-aluminized earlier in the week. A delicate, fiddly job that would take much of the day. There will, of course, be missing parts, needed tools, or other small things that we will have to get during the course of the job. Things that are at the bottom of those stairs.

Every trip up and down would be planned, this is not the time to remember that you also needed an #8-32 nut, after the climb. No forgotten items, everything thought through twice. We got the job done, a critical bit of optics safely secured back in the mount and correctly aligned.

In the end I only had to climb the stairs five times through the day.

That was quite enough, thank you.

</rant>

Soldering Small

It is always another little problem. But, on occasion, a problem is an excuse to have a little fun while getting the job done.

Enter an old WYKO interferometer with a composite video output. The gear is a critical piece of kit used to monitor the deformable mirror used in the adaptive optics system. The images from the interferometer are analyzed by a windows PC with special software. Windows, as in Windows 98!

Updating this computer has been on our to-do list for way too long. Time to get it done… When installing the new computer and video board to update this system I found that the video quality was quite bad. It would tear about halfway down the image, something wrong with the horizontal sync? Looking back it was not great on the old system, but usable. On the new system it was just not going to work.

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Out to the Lava… Again

It was another hike out to see the lava. Not that I really need an excuse to make this hike. This time it was to take a friend along. I have worked with Olivier for several years, between the two of us we do much of the physical maintenance on the Keck adaptive optics systems. Shortly he will be departing the island for another opportunity. Before he leaves he wanted to cross off one more item from his bucket list, seeing the lava close up.

The ocean entry at Kupapaʻu
Unlike last time we found the ocean entry was going strong, lava pouring into the sea very near where we saw nothing in December. There were multiple small entries spread along hundreds of yards of sea cliffs. On the west end of a shallow bay, we could get a decent look from promontories on the east end, upwind of the acrid plumes. Right below us was one particularly good font of lava, in reach of a modest telephoto lens.

It was still completely dark, the light of the full moon masked by the clouds. The waves were lit by the crimson glow, occasionally surging against the cliffs and hiding the lava from view. The glow also illuminated the billowing clouds of steam rising above each rivulet of lava. The scene is surreal, something that is both unexpected and somewhat difficult to believe. This is something that is outside our usual daily experience.

Pāhoehoe
An active pāhoehoe breakout at Kupapaʻu
After spending some time at the ocean entry we searched inland for a breakout we could approach more closely. A slight glow to the north indicated a possible breakout, but I had no idea if it was close or miles away. With hope we headed for the glow and got lucky. It was only about a quarter mile to the breakouts. Several lobes of lava were advancing over the slightly older flows. Dropping our gear well back from the active lava cameras were deployed. This is what we came to see and photograph, lava as close as the heat would let us get.

Olivier Martin
Olivier hiking over the lava at Kupapaʻu
For two hours we shot the breakouts. As usual, the flow would crust over, just to break out and advance again. The changing flow would provide ever different photo opportunities as the light of dawn slowly waxed. It was a cloudy day, small showers moving through, softening the dawn light and making the hot glow stand out all the more. The photos and video capture the scene, but do poor justice to the sound. The crackle of the cooling crust, raindrops hissing on the hot surface, low resounding cracks from deep in the rock under our feet.

With the day well begun we headed back to the ocean entry to shoot a few more frames in the early light. We sat on rock that was fairly warm under us, shooting the lava pouring into the waves. Relaxing a bit, digging a few bites to eat from the pack, we talked of cameras and lenses, of life on the island, a last bit of camaraderie with someone I might never meet again. We sat and just enjoyed this spectacle of raw nature. This was why we came, there is some risk in just being here, but the experience is worth it.

Testing TBAD with UAVSAR

So we have a system that will detect aircraft and shutter the laser.

First Target of the Night
The Keck 2 laser acquires the first target of the night with the glow of sunset behind
It works… We think.

In theory TBAD will detect the TCAS transponder on an aircraft, turning off our AO Laser to avoid illuminating the aircraft. This work via means of a directional antenna mounted to the front of the telescope that is able to detect the 1090MHz TCAS transmissions from the aircraft. The system has been operational for the better part of a year, mounted to the Keck 2 telescope. It operates all the time, whether or not we are using the laser.

The problem is that there is very little air traffic over the summit, it is even more rare that a plane goes directly in front of the telescope while we are observing. It is these test cases we need to prove the system, an aircraft passing through where the laser would be. Though the first year of running the system we logged a total of one detection that would have resulted in a laser shutter event. We need more test cases if we are to prove to the FAA that the system works as designed.

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