Astronomy – Page 83 – A Darker View

The Bright Spots on Ceres

As the Dawn spacecraft settles into lower orbits around Ceres the photos of this small world are of ever better resolution. The mysterious bright spots have slowly resolved into an interesting arrangement of multiple spots. Despite many wild claims on YouTube and UFO websites of alien cities or crashed spacecraft, the spots are looking more and more like a set of ice outcroppings. They are still fascinating, if just a bit more ordinary than some would hope.

My bet? Some sort of cryovolcano.

JPL Press release…

NASA’s Dawn mission captured a sequence of images, taken for navigation purposes, of dwarf planet Ceres on May 16, 2015. The image showcases the group of the brightest spots on Ceres, which continue to mystify scientists. It was taken from a distance of 4,500 miles (7,200 kilometers) and has a resolution of 2,250 feet (700 meters) per pixel.

“Dawn scientists can now conclude that the intense brightness of these spots is due to the reflection of sunlight by highly reflective material on the surface, possibly ice,” Christopher Russell, principal investigator for the Dawn mission from the University of California, Los Angeles, said recently.

Dawn arrived at Ceres on March 6, marking the first time a spacecraft has orbited a dwarf planet. Previously, the spacecraft explored giant asteroid Vesta for 14 months from 2011 to 2012. Dawn has the distinction of being the only spacecraft to orbit two extraterrestrial targets.

The spacecraft has been using its ion propulsion system to maneuver to its second mapping orbit at Ceres, which it will reach on June 6. The spacecraft will remain at a distance of 2,700 miles (4,400 kilometers) from the dwarf planet until June 30. Afterward, it will make its way to lower orbits.

Ceres White Spots — This image of Ceres is part of a sequence taken by NASA’s Dawn spacecraft on May 16, 2015, from a distance of 4,500 miles (7,200 kilometers). Image Credit: NASA/JPL-Caltech/UCLA/MPS/DLR/IDA

A Night on the Summit

A photographer needs a guide around Keck for the night? Setup time-lapse cameras throughout the facility? Sounds like fun… Sign me up.

Thus I meet local photographer Jason Chu at Keck in the afternoon and help him drag a mountain of camera gear into the summit facility. We loaded quite a pile onto the cart, eight full DSLR cameras and a stack of tripods. The plan is to set them up in the domes for the night then re-collect the cameras in the morning. Six cameras in the domes and a couple more to carry through the night.

Two lasers, both aimed at the galactic center were on the schedule for the second half of the night. Andrea Ghez and her team having time on both telescopes. The weather looked a bit problematic, thick cirrus covered the sky, but the forecast called for clearing after midnight.

Jason came with a carefully drafted plan, where to set and aim each camera, timer settings, lens choice, all carefully considered. A pretty good plan too, only a few details needed changing as we placed each camera. Four cameras in Keck 1, another two in Keck 2. One camera placement was my idea… Clamped to the Keck 1 dome where it would track with the telescope. I had spent a few minutes in the machine shop putting together a solid camera clamp.

Unfortunately the clouds did not clear as predicted, thin cirrus hanging on through the night. It was clear just to the west, but stubbornly would not give us the clear skies we needed overhead. Several times it looked to clear, but the clouds would thicken again. We did have both lasers on sky for a few minutes, just enough for a few photos and not long enough to do any science.

With high hopes for some dual laser time-lapse I was ready to set up my own camera, but ended up with only a few still photos. Jason got a few nice shots during that short time, having eight cameras helped make the most of those few minutes. I did get a nice video clip of the telescope shot by rotating the dome with a camera.

Jason is working on a personal project and will be out shooting more images in the dark. I will certainly feature the results of his effort here on DarkerView when he finishes. For myself? I will have to schedule another opportunity to go up and shoot some laser time-lapse. There is an intriguing night at the beginning of July on the schedule with both Keck lasers. I also need to mail Jason a camera remote, an accomplishment that only one bit of camera gear got left behind.

Scientists at Keck Discover the Fluffiest Galaxies

W. M. Keck Observatory press release…

Ultra-Diffuse Galaxy — A collection of unidentified blobs was discovered toward the Coma cluster of galaxies, using the Dragonfly Telephoto Array. Credit: P. Van Dokkum, R. Abraham, J. Brodie

An international team of researchers led by Pieter van Dokkum at Yale University have used the W. M. Keck Observatory to confirm the existence of the most diffuse class of galaxies known in the universe. These “fluffiest galaxies” are nearly as wide as our own Milky Way galaxy – about 60,000 light years – yet harbor only one percent as many stars. The findings were recently published in the Astrophysical Journal Letters.

“If the Milky Way is a sea of stars, then these newly discovered galaxies are like wisps of clouds”, said van Dokkum. “We are beginning to form some ideas about how they were born and it’s remarkable they have survived at all. They are found in a dense, violent region of space filled with dark matter and galaxies whizzing around, so we think they must be cloaked in their own invisible dark matter ‘shields’ that are protecting them from this intergalactic assault.”

The team made the latest discovery by combining results from one of the world’s smallest telescopes as well as the largest telescope on Earth. The Dragonfly Telephoto Array used 14-centimeter state of the art telephoto lens cameras to produce digital images of the very faint, diffuse objects. Keck Observatory’s 10-meter Keck I telescope, with its Low Resolution Imaging Spectrograph, then separated the light of one of the objects into colors that diagnose its composition and distance.

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Astronomers Baffled by Discovery of Rare Quasar Quartet

W. M. Keck Observatory press release…

Using the W. M. Keck Observatory in Hawaii, a group of astronomers led by Joseph Hennawi of the Max Planck Institute for Astronomy have discovered the first quadruple quasar: four rare active black holes situated in close proximity to one another. The quartet resides in one of the most massive structures ever discovered in the distant universe, and is surrounded by a giant nebula of cool dense gas. Because the discovery comes with one-in-ten-million odds, perhaps cosmologists need to rethink their models of quasar evolution and the formation of the most massive cosmic structures. The results are being published in the May 15, 2015 edition of the journal Science.

Quasar Quartet — Image of the region of the space occupied by the rare quasar quartet. The four quasars are indicated by arrows. Credit: Hennawi & Arrigoni-Battaia, MPIA

Hitting the jackpot is one thing, but if you hit the jackpot four times in a row you might wonder if the odds were somehow stacked in your favor.

Quasars constitute a brief phase of galaxy evolution, powered by the in-fall of matter onto a supermassive black hole at the center of a galaxy. During this phase, they are the most luminous objects in the Universe, shining hundreds of times brighter than their host galaxies, which themselves contain hundreds of billions of stars. But these hyper-luminous episodes last only a tiny fraction of a galaxy’s lifetime, which is why astronomers need to be very lucky to catch any given galaxy in the act. As a result, quasars are exceedingly rare on the sky, and are typically separated by hundreds of millions of light years from one another. The researchers estimate that the odds of discovering a quadruple quasar by chance is one in ten million. How on Earth did they get so lucky?

Clues come from peculiar properties of the quartet’s environment. The four quasars are surrounded by a giant nebula of cool dense hydrogen gas, which emits light because it is irradiated by the intense glare of the quasars. In addition, both the quartet and the surrounding nebula reside in a rare corner of the universe with a surprisingly large amount of matter. “There are several hundred times more galaxies in this region than you would expect to see at these distances,” said J. Xavier Prochaska, professor at the University of California Santa Cruz and the principal investigator of the Keck Observatory observations.

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A Conversation on Mauna Kea

A night on the summit and a stay at Hale Pōhaku offers an opportunity to explore the mountain. The plan had been to take a short hike in the Hale Pōhaku area to visit some interesting geologic features before heading down the mountain. A cold misting rain made that idea much less attractive. Instead I paid a visit to my friends at the Visitor Information Station and along the way visited the protest camp across the street. The experience of the day was a conversation I had with the occupants of the camp, a conversation both interesting and odd, I spent the entire drive back down the mountain and much of the day mulling over what I had seen and heard in that conversation.

Protest Encampment — The protest encampment across the street from Hale Pōhaku

I will avoid the use of names here, I am not sure is the owners would appreciate my using them and they really add nothing to this description. Thus I will follow Galileo and use names that reflect the individual views. It is these views that were intriguing, for this day I met several people with entirely different motivations that make a very interesting contrast. It was fascinating to me that in the span of one conversation I would meet people who so typified the various groups that have become involved in the controversy.

The first to greet me as I came across the street was a gentleman I will call Mr. Sovereignty for his position on the matter. The argument atop Mauna Kea has become embroiled in a range of issues that have simmered in the islands for a long time. Among those who are against the construction of TMT are some who are simply against any further telescopes on Mauna Kea and also those who see the issue as wrapped up in questions on the legal status of the State of Hawaii. The main thrust of a common argument is that the Kingdom of Hawaii was illegally overthrown. Their goal is nothing less than the restoration of the kingdom as a sovereign entity.

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Scientists at Keck Measure Farthest Galaxy Ever

Keck again holds the record, for the moment at least, of the farthest galaxy ever observed. It is a record that we have been passing back and forth with the neighboring Subaru Telescope for some years now. We currently have the advantage of MOSFIRE, a fantastic spectrograph to discover these objects. I expect our hold on this title will be transitory, there are candidate objects that may even be somewhat further away and back in time.

EGS-zs8-1, the farthest confirmed galaxy observed to date. Credit: NASA, ESA, P. Oesch and I. Momcheva (Yale), and the 3D-HST and HUDF09/XDF teams

Why try to observe these galaxies? They tell us a great deal about the formation of the first stars and galaxies after what astronomers call the “Dark Ages”, a period of time after the Big Bang when light could not travel through the galaxy, absorbed by a fog of neutral hydrogen. These first stars and galaxies ionized this hydrogen, creating the transparent universe we see today. By studying these galaxies we learn a great deal about how the universe we see today came to be.

W. M. Keck Observatory press release…

An international team of astronomers, led by Yale and the University of California, Santa Cruz, pushed back the cosmic frontier of galaxy exploration to a time when the Universe was only five percent of its present age. The team discovered an exceptionally luminous galaxy more than 13 billion years in the past and determined its exact distance from Earth using the powerful MOSFIRE instrument on the 10-meter Keck I telescope at the W. M. Keck Observatory in Hawaii. These observations confirmed it to be the most distant galaxy ever measured, setting a new record. The findings are being published in Astrophysical Journal Letters today.

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Another Peek into CFHT

Upgrades. With 20 year old systems upgrading and replacing old gear is a constant job. It is even worse over at CFHT, their facility is quite a bit older than ours at Keck. Does this mean the telescope is obsolete? No way. most systems have been constantly updated with new technology. But it does take quite a bit of work…

Canada France Hawaii Telescope Upgraded TCS testing from CFHT on Vimeo.

A Matter of Time

Time… It is simply a matter of time. At 00:00UT May 3rd, many of the observatory computers suddenly started reporting that the date was September 17th, 1995. To say that this created some problems is a dramatic understatement.

Datum TS2100 Time Servers — Two Datum TS2100 time servers installed above the telescope drive control computer (TDC)

The problem came from the primary observatory clock. This clock, properly called a time server, uses GPS signals to create a time reference that is accurate to microseconds. This is made possible by referencing to the atomic clocks carried by each GPS satellite. A time server is intricately connected to the network to distribute this time. Any computer in the building can ask it for time via the NTP protocol, but that has some inaccuracy due to network delays. For equipment requiring more precise time the server distributes a hard wired time reference using the IRIG-B protocol or a 1PPS timing pulse.

Without accurate time a telescope will simply not point in the correct direction. The calculation that the computers perform must take into account our rotating planet. Feed incorrect time to that calculation and you will point to the wrong piece of sky. A few milliseconds off can result in a pointing error of arcseconds, a large error for a large telescope.

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The Work of Protecting Mauna Kea

Walking into the building I saw the first sign. A prominent message placed in the windshield of a car parked by the entrance… “TMT, Too Many Telescopes” The protesters were here. I had hoped they would not be, we had things to get done in this meeting. A disruption of the meeting by protesters would mean another delay.

Too Many Telescopes — A protest sign in the window of a car outside the OMKM board meeting

The event was the regularly scheduled meeting of the Mauna Kea Management Board. The board is a group of community members who volunteer their time to the work of protecting Mauna Kea. I was here because Keck Observatory wants to install a set of new weather instruments atop our building and domes. Any change to the external appearance of the structure, however minor, requires approval of the Kahu Kū Mauna council, the Mauna Kea Management Board and the Department of Land and Natural Resources.

To that end I had written a proposal for the new instruments with a description of exactly what we wished to do. Attached is an appendix of photos and drawings to answer any possible questions. I was present to answer the inevitable questions I had not thought of and feared would get asked.

The room was filling rapidly when we arrived, far beyond the usual audience of one of these meetings. As I greeted the many people I know, I noted many new faces. They seemed out of place, a little on edge, a sense of having entered enemy territory. Many of those present were young, in their teens and early twenties, one a young mother, child carried in her arms. The t-shirts betrayed their allegiance, they came with cameras and poorly concealed protest signs.

I have no problem with those who oppose the telescopes atop Mauna Kea attending a meeting like the OMKM board meeting. Public participation is a good thing. Indeed, these meetings are open to the public for a reason, to allow anyone interested to attend and to see for themselves how those charged with managing the mountain do their jobs.

I worried about a protest that would disrupt the meeting, making it impossible to accomplish anything. This did not happen. I will give those who attended credit for showing respect for the proceedings and to those discussing the effort of caring for the mountain.

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Category: Astronomy