Keep it Running

Some equipment around the observatory is thirty or more years old. As you would expect, keeping it running can be a challenge.

A redesigned small signal PCB for an Inland Motor FCU-100-30 amplifier power supply
A redesigned small signal PCB for an Inland Motor FCU-100-30 amplifier power supply

There are two ways of dealing with this old equipment… Replacing it with something new is the preferred way. When it becomes difficult to locate spare parts, when it breaks down too often, just replace it with new gear. For much of the equipment this is the usual answer and is often a major part of the job.

Some equipment is not so easily replaced. When replacement would require wholesale redesign of a system it becomes more of a challenge. Sometimes the only choice is to keep that old gear running.

This is the case with our servo amplifiers. Twelve amplifiers supply the power that drives the telescope, one amplifier for each motor. Eight amplifiers and motors drive azimuth, four drive elevation. Three hundred and seventy tons moved by twelve relatively small DC motors. While much of the telescope control system was recently replaced, it was decided to keep the old servo amplifiers.

You might notice that these servo amplifiers are just a wee bit critical.

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A Very Unstable Day

The ground beneath us is one constant in life you just expect to never change. Solid and unyielding, we build our lives upon the firm foundations of the Earth. When this constant betrays us it is truly disconcerting. The world loses some of its comforting stability.

Last Friday was a day when our islands were reminded of the instability of our world in a rather abrupt fashion.

USGS Earthquake Map for 1May2018
USGS Earthquake Map for May 6, 2018
It was clear weeks ago that the volcano was restless. volcanophiles like myself found ourselves checking the reports and charts daily. The deformation graphs are a good indication of what is going on inside the volcano.

The tiltmeters indicated that pressure in the caldera and Puʻu Oʻo had been building steadily. At the same time the activity in the 61g lava had been waning. Where was the magma going?

While speculation was rife, no one really knew what was coming. Three decades of eruptions from Puʻu Oʻo has become somewhat routine. People forget that Kilauea can be, and usually is much more unpredictable. That destruction can appear anywhere on her flanks.

USGS Leilani Eruption, 5 May, 2018
Lava emerges from a fissure in the Leilani Estates subdivision on May 5th, 2018, photo from the USGS
The first lava surfaced Thursday afternoon in the neighborhood of Leilani Estates. The observatory staff had gathered to celebrate a pau hana that afternoon, an early Cinco De Mayo celebration with Mexican food. Many of us ate our tacos and quesadillas in the conference room, where the large screen was showing drone video of the first fissures.

We worried about the homes in the neighborhood and the people we knew who lived in the area. We compared notes, recalling who lived exactly where, fearing the lava flows would quickly spread. This was looking like a worst case scenario, a repeat of 1955 with more people and homes in the way.

Despite the outbreaks of lava in the rift zone the previous afternoon, we expected a routine Friday atop Mauna Kea. I had a list of tasks to complete… Inspect the K1 azimuth wrap, drill some anchor points to allow installation of the new ice monitor receiver on the roof, look for some spare parts for an encoder.

It should be an easy day on the summit… It was not.

Friday became a day I will remember for a long time to come.

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Dual Laser Milky Way Photo Op

The island is home to a vibrant community of photographers, a mix of professionals and serious amateurs. There is one set of photos everyone, and I do mean everyone wants… Dual lasers on the Milky Way.

Dual Lasers on the Galactic Center
Both Keck lasers aimed at the center of the Milky Way galaxy
Just occasionally both of the keck telescopes, and both lasers, are focused on the center of the galaxy, both stabbing right at the heart of the Milky Way.

Opportunities to see and photograph this are few, and occur strictly during the summer months of June to August, when the Milky Way is high overhead. furthermore, these opportunities occur only when Andre Ghez and her UCLA Galactic Center Group have both telescopes scheduled.

July 25th was such a night, a good opportunity to get both lasers. Andrea’s group has the first half of the night, turning over the ‘scopes to other astronomers just after midnight. Actually there were a few nights this particular week, we just chose the 25th. After this galactic center season is over, at least until next year.

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Shooting Sidereal Timelapse

Another night on the summit for photography, another night of dual lasers working the sky above the Keck telescopes.

Sidereal Drive Platform
A Celestron telescope drive configured as a sidereal rate tracking camera platform
I have never really had a chance to properly use the old Celestron mount for photography after finishing it a few months back. Short tests, but nothing properly following the sky for hours on end as the equipment was meant to do.

It works, and it works very well indeed.

The video below contains 2.5 hours of time-lapse at 15 second for each exposure for 557 frames. Put that together and render at 24fps and you have the following result…

Service Call

It does not happen very often, but it does happen. Driving up to the summit in the night to fix the telescope. As an operations engineer it is part of the job, but I can think of only a handful of times in my decade on the summit I have actually done it.

The motor controllers for the Keck 2 top shutter
The motor controllers for the Keck 2 top shutter
Considering it takes the better part of two hours to get to the summit there is no point in trying unless the issue occurs early. You have to consider the issue… Can you fix it in the middle of the night? Will there be any night left once you fix it? Do you just call the night and head up the next day with a full crew and a good night’s rest to fix it properly?

This particular problem was discovered first thing upon opening. Well? Lack of opening for the night. The top shutter on Keck 2 would not move, fault lights all over the place. Hard to look at the sky with the top shutter closed. I worked the issue over the phone for a while with Nick as far as we could.

The conclusion? I would have to work the problem in person to fix it, I have to go up.

Can I fix this? Probably. I found myself leaving the house before 9pm for a run to the summit.

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Unexpected Classification of Exoplanets Discovered

W. M. Keck Observatory press release

Since the mid-1990s, when the first planet around another sun-like star was discovered, astronomers have amassed an ever-expanding collection of nearly 3,500 confirmed exoplanets.

Exoplanet Formation
Assembly Line of Planets: This diagram illustrates how planets are assembled and sorted into two distinct size classes. Image credit: NASA/Kepler/Caltech (R. Hurt)
In a new Caltech-led study, researchers have classified these exoplanets in much the same way that biologists identify new animal species and found the majority of exoplanets fall into two distinct groups: rocky Earth-like planets and larger mini-Neptunes. The team used data from W. M. Keck Observatory and NASA’s Kepler mission.

“This is a major new division in the family tree of planets, analogous to discovering that mammals and lizards are distinct branches on the tree of life,” says Andrew Howard, professor of astronomy at Caltech and a principal investigator of the new research.

The lead author of the new study, to be published in The Astronomical Journal, is Benjamin J. (B. J.) Fulton, a graduate student in Howard’s group.

In essence, their research shows that our galaxy has a strong preference for either rocky planets up to 1.75 times the size of Earth or gas-enshrouded mini-Neptune worlds, which are from 2 to 3.5 times the size of Earth (or somewhat smaller than Neptune). Our galaxy rarely makes planets with sizes in between these two groups.

“Astronomers like to put things in buckets,” says Fulton. “In this case, we have found two very distinct buckets for the majority of the Kepler planets.”

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