Category: Astronomy
Exploring the cosmos
A Fogbow, A Glory and the Spectre of the Brocken
When doing a dawn hike on Mauna Kea it is important to choose your altitude with care. You really want to be right at the top of the cloud layer. There, where the fog drifts over in alternating shifts with the sunlight, there is where the magic happens. Mamane in the fog, puʻu appearing and disappearing, and fogbows. Add fog and you have all the ingredients for some good photography.
The plan had been to spend the morning on the summit doing some testing. When that got cancelled I quickly dropped into plan B… Go hiking. I got the altitude right.
The spectre of the brocken was a nice treat. At the center of the fogbow you can see a glory, and in the center of the glory is my shadow looming large in the mist. That is the spectre.
Unusual Asteroid Suspected of Spinning to Explosion
W. M Keck Observatory press release…
A team led by astronomers from the Jagiellonian University in Krakow, Poland, recently used the W. M. Keck Observatory in Hawaii to observe and measure a rare class of “active asteroids” that spontaneously emit dust and have been confounding scientists for years. The team was able to measure the rotational speed of one of these objects, suggesting the asteroid spun so fast it burst, ejecting dust and newly discovered fragments in a trail behind it. The findings are being published in Astrophysical Journal Letters on March 20, 2015.
Then in 2010 a new type of active asteroid was discovered, which ejected dust like a shot without an obvious reason. Scientist gravitated around two possible hypotheses. One states the explosion is a result of a hypervelocity collision with another minor object. The second popular explanation describes it as a consequence of “rotational disruption”, a process of launching dust and fragments by spinning so fast, the large centrifugal forces produced exceed the object’s own gravity, causing it to break apart. Rotational disruption is the expected final state of what is called the YORP effect – a slow evolution of the rotation rate due to asymmetric emission of heat.
Continue reading “Unusual Asteroid Suspected of Spinning to Explosion”
Vernal Equinox
The vernal or spring equinox occurs today at 12:45HST. Today there will be little difference between the length of the night when counted against the number of daylight hours. This is the first day of spring as marked by many cultures in the northern hemisphere.
| 2015 Solstices and Equinoxes | ||||
|---|---|---|---|---|
| UT | HST | |||
| Perihelion | Jan 4 | 08:59UT | Jan 3 | 22:59HST |
| Vernal Equinox | Mar 20 | 22:45UT | Mar 20 | 12:45HST |
| Summer Solstice | Jun 21 | 16:38UT | Jun 21 | 06:38HST |
| Apehelion | Jul 6 | 12:59UT | Jul 6 | 02:59HST |
| Autumnal Equinox | Sep 23 | 08:20UT | Sep 22 | 22:20HST |
| Winter Solstice | Dec 22 | 04:48UT | Dec 21 | 18:48HST |
| Source: NASA Sky Calendar | ||||
A Matter of Control
As the new year is well underway I find myself in the midst of my major project for this year. For the next few months I will be replacing the control system for the Keck 2 dome. The project is well underway, but the real work remains ahead of me.
Parts for the PLC/2 are still available, but the programming software is a real issue. The software runs on a DOS (as in pre-windows) operating system, and does not run under the emulation modes of later Microsoft systems. You need a real DOS computer, something that is a bit rare these days. If the controller running the Keck 2 dome were to fail, I am not certain we could repair it.
I have the computer that is used to do the programming in my office, an ancient Compaq Portable III. Portable is an odd word to use with this computer, it weighs over 20lbs and is huge by modern laptop standards. This museum piece still works! Last month I booted it up and wandered through the file system. At power up I was greeted by a monochrome amber screen and a DOS prompt. I still remember a few basic DOS commands, enough to check things out. It appears that all of the software and files are still present on the hard drive. Sometime I need to see if I can indeed program the old PLC/2. If something goes wrong in the update I need to be able to revert to the original control system.
Switches
Public Lecture Reminder
A reminder that the Keck public lecture is tomorrow night…
Astronomy Talk: America’s Space Program – NASA’s Roadmap to Tomorrow’s Missions
The agency currently has spacecraft speeding toward Jupiter and Pluto and roving on Mars, and is searching for planets that could potentially harbor life beyond our solar system. An unprecedented mission to capture and redirect an asteroid to an orbit near to Earth is in the planning stages, and the Space Launch System and Orion Crew vehicle are reaching new milestones in development to take astronauts to an asteroid and on to Mars.
NASA has been a 1/6 partner in the W. M. Keck Observatory since 1996 and it is an honor to offer this program to the community.
Friday March 13, 2015
07:00 pm – 08:00 pm
Kahilu Theatre
Waimea
Free Admission
The Aftermath of the Storm
The storm appears to be waning now, the satellite shows that much of it has passed the island. Not long ago the snowplow crews let it be known that they would not reach the summit today, try again tomorrow as the storm abates.
I did a bit of a photo survey of the summit using MastCam to check on the summit conditions. Poliʻahu rules Mauna Kea!
The Blizzard Continues
The storm continues unabated atop Mauna Kea. Word from the snowplow crews is bad, deep drifts cover the road above the switchbacks. They are stating that it is unlikely our summit crew will be able to access the telescopes today. That will make the second day in a row with no access.
MastCam is still functioning, only half the dome is covered with ice. I have turned the heater on in an attempt to clear what I can. The view it reveals is deeper snow and a lot more ice. The railings on the dome ladders have coatings many inches thick.
Why is the Summit Road Closed?
Folks sometimes get a little perturbed when MKSS closes the Mauna Kea summit road. Everyone wants to go up and see the snow. Yes, the road is closed right now, for good reason, there really is no accessible road on the summit at the moment. Not taking my word for it? See for yourself…
