Postcard from the Summit – Snowy SMA

Winter has arrived on Mauna Kea. the last few weeks have brought regular snow, ice and fog to the summit. Quite a few nights have been completely or partially lost to weather. We always wonder what winter will bring. In the last few years I have seen winters with hardly a lost night, and no substantial snowfall. Other winters I have helped dig our way into the building. What the winter of 2011-2012 will bring? We will just deal with what Poli’ahu delivers.

Snowy SMA
The SMA antennas in snow and fog

Article in the North Hawaii News

CB52-80-07286-DCLarry, our PIO officer asked me to write an article about Keck for the North Hawai’i News. He has arranged for us to get a nice one page article into this local weekly paper each month. This month I contributed the text and photos for the Nov 10th edition.

It is interesting to write a piece for a more traditional format. With the added advantage of having a professional do the editing, with feedback. The result is much like the articles I have written for Darker View. Some rehashing of material I have used here, but re-written to provide a more complete story. The photo below is the one chosen by the editor to illustrate the article.

Pushing Steel

A snippet of overheard conversation. I was in Keck 2 control talking with the operator when a few words drifted over the video conference link from Keck 1. Some sort of trouble. I headed for the other end of the building.

Sniffen, our night attendant was looking for the cause of a drive fault. For some reason the computer refused to move the telescope, displaying a drive fault error. It would not move manually either, drive power would not come on. As he explained this to me I was a bit worried. This could be really simple, or really bad. Possibly something that would cost us the night.

Fisheye Keck 1
The Keck 1 Telescope awaiting lights out and release for the night
Opening the doors to the drive electronics cabinet I began decoding the cryptic status and error LED’s on the interlock control boards. Dozens of unlabeled indicators with a chart pasted to the door, a bit of 1980’s tech we still have to deal with, upgrade scheduled for the year after next. It takes a few moments… Right Final Limit error?

Sniffen and I looked at each other… How had the computer driven into a limit? This was not supposed to be possible. While we occasionally put the scope in a limit during maintenance, I had never heard of this occurring during the night. Was it really in the limit? The computer was indicating we were well clear of the limit. Something was lying to us.

Walking out into the dome and looking up confirmed we actually were on the limit switch. The telescope had driven as far around in azimuth as it could go, stopping just before the hard stop, a massive steel assembly that will definitely stop the telescope.

Oh !#%$! We have to push.

Yes, it is possible to push 300 tons of steel when it is floating on a film of oil. I have never had a chance to do it myself, but years ago someone had shown me how to do it. With Sniffen pressing a pair of pencils into the electrical contactors to release the brakes, I shoved the telescope out of the limit.

It moves surprisingly easy. I had braced my back against the laser enclosure and put my feet against the steel rails used to move the instruments. One good shove and it was moving. I really did not need to brace so well, just a good hard lean against the railings would have done it.

Once you get 300 tons of steel moving, it keeps moving. After I stopped pushing it continued to glide for another few degrees. Low friction creating a clear example of Newton’s first law of motion.

A surreal experience… 2am, in a darkened dome with stars overhead, pushing one of the world’s largest telescopes by hand. Life is interesting sometimes! Twenty six minutes of precious dark lost, but with a quick reinitialization of the telescope we were back on-sky.

Postcard from the Summit – Laser Panorama

Assembling panoramas properly is not a trivial exercise. I have been attempting to master a program called Hugin and may have achieved some modest level of competency with it. It is surprising complex, and extraordinary powerful. Even more impressive as it is free software. Properly mastered it allows correction of tip, tilt and yaw in the camera, lens distortion, even translation of the camera’s position in x,y, and z. The task is made even more complex if the scene changes during the sequence, which is inevitable during the fifteen minutes it takes to sweep a moonlit scene on the observatory roof with one minute exposures. The stars move, the telescopes move, while I try not to shiver uncontrollably in the bitter wind.

Laser Panorama
A moonlit panorama from the roof of Keck during a night of laser engineering

Keck and a Nobel Prize

We are celebrating a bit at Keck today. It is somewhat unusual for an astronomer to be awarded the Nobel Prize in Physics. Today it was announced that three astronomers will share the award for their work in cosmology. Saul Perlmutter, Brian Schmidt, and Adam Riess led a pair of teams that were investigating the expansion of the universe through observing type Ia supernovae. Saul Perlmutter led the Supernova Cosmology Project, while Brian Schmidt and Adam Riess led a separate group, the High-Z Supernova Search, performing nearly identical work.

Both teams discovered something disturbing in the data. The expansion of our universe appeared not to be slowing as astronomers expected, but actually accelerating. The result, had both teams scrambling to understand the data, checking and triple checking everything in an attempt to see where they had gone wrong in their analysis. When each team finally published they were glad to see that they were not alone, that another group had independently confirmed this unexpected discovery.

A couple decades later we have come to accept this result as further data has accumulated. We now understand that there is another element of the universe that had not been appreciated before. What the astronomers had found was the effects of something that had been hinted at in a number of physicists theories (including Einstein), something we now call Dark Energy.

SN2011fe in M101
Type Ia supernova, SN2011fe, in the galaxy M101
The teams used a number of different telescopes in a coordinated effort to both discover and then obtian the spectral data on the supernovae. Smaller telescopes would be used to discover the supernovae, searching wide swaths of sky looking for these rare events. Then the team would use large telescopes, like Keck, to gather the spectral data of the supernovae. The spectra would confirm the event as a type Ia supernova and give the redshift.

The most critical data, the spectra of the furthest and faintest supernovae, were made possible by the Keck telescopes, then the largest in the world. It is these most distant objects where the effect of our universe’s accelerated expansion is most noticeable. Looking through the tables of data in the original scientific papers, the Keck Observatory is often credited.

It is somewhat unfortunate that only a few individuals are named with a Nobel Prize. The discovery of dark energy and the acceleration of the expansion was an effort made by teams of individuals. Both supernovae search teams and all the members deserve real recognition for this. In turn their efforts depended on the staffs of the observatories that made the observations possible. Big discoveries are rarely made by individual scientists, but by the cooperative effort of many. There are only three names on the Nobel Prize, but a lot of folks are celebrating today.

Shaken and Back On-Sky

I understand it was quite the scramble, but both telescopes are back on-sky tonight.

The earthquakes started just after two this afternoon with the magnitude 4.5 event that got our attention so quickly. This gave day crew three hours to have everything inspected, checked out and ready for the night. Physical inspections, instrument checkouts, and more, an extensive checklist to follow and insure that no real damage was done by the temblors. Just after 5pm we got word that everything was good-to-go and both telescopes would be released for the night’s observing.

As of writing this, about ten hours after the first quake, there have been 32 separate events under Mauna Kea detected by the seismographs. A half dozen of those were near magnitude three. I have felt thirteen separate aftershocks, this plus the original quake makes fourteen, the most I have ever felt in a single day by a wide margin.

The USGS has released a statement noting that this was probably a “structural adjustment” a result of the enormous weight of Mauna Kea stressing the underlying rock…

Magnitude 4.5 earthquake on the north flank of Mauna Kea

By USGS/HVO

Hawai‘i Island, HAWAII—The U.S. Geological Survey’s Hawaiian Volcano Observatory (HVO) recorded a magnitude-4.5 earthquake located beneath the Island of Hawai‘i on Wednesday, October 19, at 2:10 p.m. HST. This earthquake was centered about 9 km (6 mi) northwest of Mauna Kea’s summit and 49 km (31 mi) west-northwest of Hilo, at a depth of 18.7 km (11.6 mi).

The earthquake was widely felt on the Island of Hawai’i. The USGS “Did you feel it?” Web site (http://earthquake.usgs.gov/eqcenter/dyfi/) received more than 500 felt reports within an hour of the earthquake.

The earthquake was the largest in a cluster of about 20 earthquakes on the north flank of Mauna Kea on Wednesday afternoon. Most of these aftershocks were too small to be felt, but, as of 3:30 p.m., two earthquakes with magnitudes greater than 3.0 had occurred in addition to the magnitude-4.5 event.

Over the past 25 years, the north flank of Mauna Kea has experienced 10 earthquakes greater than magnitude 4.0, including today’s event, at depths of 10–40 km (6–25 mi). Deep earthquakes in this region are most likely caused by structural adjustments within the Earth’s crust due to the heavy load of Mauna Kea.

Adjustments beneath Mauna Kea during past similar events, such as in March 2010, have produced a flurry of earthquakes, with many small aftershocks occurring for days after the main quake. Given this history, it is possible that additional small earthquakes may be recorded in the coming days.

Today’s earthquakes caused no detectable changes on the continuing eruption of Kilauea Volcano.

For eruption updates and information on recent earthquakes in Hawai’i, visit the Hawaiian Volcano Observatory website at http://hvo.wr.usgs.gov

More Shaking

This is starting to look ominous! Nineteen events so far and counting, it seems the building rattles every 10-20min with another aftershock. Will it please settle down?

Word is that Keck1 is fine, we are scheduled to do some engineering with the AO laser. The laser itself is still on and operational, a minor miracle. There may be some issues with Keck 2 after the initial quake. We are waiting for a more detailed report from the summit crew.

Earthquake Swarm
An ongoing earthquake swarm underneath Mauna Kea, 19Oct 2011

Laser Susan

The old saying “Necessity is the mother of invention” has a certain truth to it.

In this case the necessity is created by the conditions. Sub-freezing temperatures, bone chilling wind, and the need to be outside under these conditions. The summit of Mauna Kea can be downright miserable for mere human beings. Yet, in order to operate the laser, someone has to watch and insure we do not illuminate some passenger aircraft on the way to Australia.

Thus we have laser spotters, a hardy crew indeed. Braving the conditions, spending hours watching the sky to insure we operate safely. We are attempting to introduce technological solutions to the problem. The FAA however is an extraordinarily conservative organization, rightly so when hundreds of lives are at risk on any given flight. It takes time, many years, to approve another method of insuring safe laser operation.

It is a cold job. I have done it for a few hours, just enough to instill a real respect for the guys who do it all night. You bundle up in many layers of insulation and attempt to get comfortable in a position that allows observation of the area of sky around the beam. Given the heavy clothing it is a pain to simply sweep the sky, and completely reposition each time the telescope changes target.

Given the problem, Doug Macilroy, one of our intrepid Keck crew, saw a solution. It took time, and a number of prototypes to get it right. But he now has a neat way to stay comfortable and warm while scanning the sky. Now we have the “Laser Susan”!

YouTube video for the Laser Susan

Neptune and Triton

Mike Brown did more than give a lecture while in Hawai’i. He just finished a four day observing run using Keck 2 with AO and OSIRIS, as well as gathering data with NIRSPEC. The target? Among other things Mike and his team observed Neptune and the large moon Triton. Triton is thought to be a captured KBO (Kuiper Belt Object). These objects, including well known Pluto, and lesser known, but just as large objects like Eris, Haumea, Makemake and Quaoar, are Mike’s area of expertise.

It is always nice to see a system I help maintain operating well and producing images like this…

Triton and Neptune
A Keck AO / OSIRIS photo of Neptune and the large moon Triton, credit Mike Brown/CalTech