A Hole-Punch Cloud

We were just setting up the telescopes when I looked up and spotted it.

Waikoloa School was hosting a community picnic, a couple bands, food, performances by a karate club and a halau, plus a few telescopes provided by Keck and the West Hawaii Astronomy Club. It promised to be a fun evening.

What I spotted was a hole-punch cloud above the school. OK, that was unexpected. A high thin layer of altocumulus perforated by a neat circular hole.

The hole had a thickened edge as if something had pushed the cloud layer aside. Otherwise it was completely clear in the center and nearly perfectly circular.

Hole punch clouds are often formed when something passes through a cloud layer, such as an aircraft, disturbing and destabilizing it. This does not appear to be the case here, rather I would guess that an updraft from below pushed its way into this particular cloud from below.

The hole was short lived, fading in about 15-20 minutes as the cloud layer reformed.

A Hole-Punch Cloud over Waikoloa
A Hole-Punch Cloud over Waikoloa School

A Tale of Two Earthquakes

Two earthquakes of the same magnitude strike our island a month apart. Two events that are quite interesting to us at the observatory. Both about the same magnitude, both occurring deep in the island, one was far more forceful at the telescopes causing some minor damage, the second caused no damage that we have found despite a thorough inspection.

Mauna Kea seen at dawn from Mauna Loa
Mauna Kea seen at dawn from Mauna Loa

Any strong earthquake is a concern for the telescopes. We need to know immediately just how strong the quake was, how much potential for damage occurred.

The telescopes are precision instruments with many delicate parts. On the other hand earthquakes are common on this volcanic island and we have learned how to deal with the shaking.

When attempting to measure the possible damage to the telescope it is not earthquake magnitude that is interesting. Rather we want to know the peak ground accelerations that occur at the summit facility. The actual forces that could potentially cause damage. These are measured by means of a logging accelerometer mounted in the basement of the observatory.

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A Threshold of Knowledge

How can someone possibly believe that the world is flat? Evidence our world is a sphere can be found everywhere you look, yet many insist that photos of a globe are lies. How can anyone believe the world is only a few thousand years old? There are literally mountains of evidence for an ancient planet 4.5 billion years old.

Chang'e 5 Earth and Moon
The Chang’e 5 test vehicle service module took this photo of Earth and the Moon together. Credit CSNA

There are so many such beliefs floating about, and a surprising number of die-hard adherents to such fallacies. Yet they persist, and in this internet connected world some of these ideas flourish.

There are many reasons for such beliefs. Some occur as they seem right and are accepted without critical examination. Other beliefs are strongly held as a result of indoctrination from a young age. Once embedded deeply into a worldview such beliefs are very difficult to dislodge.

There is one factor that can be seen in most, if not all adherents to alternate worldviews… A lack of fundamental knowledge about how the world works, a lack of breadth to that knowledge. They have never reached a critical threshold of understanding, they never develop a good personal method of evaluating ideas, of testing against the evidence.

Once you reach a certain point in understanding our world, when you have learned enough to start making sense of that body of knowledge, you start seeing the connections, you gain an understanding of the whole. Proper understanding allows new ideas to be tested, to see how any new idea fits into the whole, to see the supporting connections.

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A Point Without Shadows

I have run into a significant problem I did not expect.

Flying in the Humuʻula Saddle
Flying the drone in the Humuʻula Saddle region on the way to work
I love to fly the drone in the Humuʻula Saddle in the morning and afternoon. It is an area that I find endlessly fascinating, with spectacular scenery in a dramatic landscape.

Even better, I need only stop off on the way to or from work at the summit to find time to fly here. Leave for work early, discharge a few flight batteries, join the rest of the crew for breakfast at Hale Pōhaku.

Just after dawn or just before sunset the light accentuates this dramatic landscape, intensifying the colors, the low sunlight angle creating shadows that reveals the stark terrain.

The low sunlight angle causes some problems as well. One I expected… The drone camera does not deal well with glare. Take an image pointing near the Sun and the image is often ruined by the glare. This is discussed in some of the review videos I watched before I bought the drone. Easy to avoid, just point away from the Sun before you start that panorama sequence.

The second major issue I did not expect… Many of the images feature a very bright spot directly opposite the Sun in the sky. This spot is intense, creating a peculiar feature in the photograph that I find distracting.

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The Impact of Totality

Having recently viewed a total solar eclipse I have been thinking about the experience. What it was like to observe first hand a truly incredible spectacle of nature? A total solar eclipse is about as dramatic an event our world can produce.

Total Solar Eclipse 2017
The 2017 total solar eclipse as photographed from central Oregon
This is not my first total solar eclipse, but that first eclipse was back in 1979, occurring 38 years ago, my memories dimmed by the passage of time. This event is still bright in my mind, the memories bolstered by numerous photographs and a couple video records.

The experience was astonishing. For the first thirty seconds or so I simply sat in amazement, observing the eclipse and the world around me. Despite old memories and numerous photos I was still amazed by the sight. I knew what was coming, but I was to some extent unprepared for the sight before me. Eventually I gathered my thoughts and took some photos before the fleeting moments of totality expired.

In these modern times we rarely encounter a natural phenomena we are completely unprepared for. Prior to the event we have seen photographs or video, read descriptions from others. We generally know what we are about to encounter beforehand, or at least have a name and a cause we can understand when caught by surprise.

Imagine if that was not the case, consider seeing a total solar eclipse when you have never seen one, never even heard of such a thing, and do not know something is about to happen.

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The Eclipse Petroglyph

Among the petroglyphs at Horsethief Lake is one that has always caused me to wonder. Of course the site is home to the famous Tsagaglalal or She-Who-Watches image. This is not the one I refer to, rather a somewhat smaller and usually overlooked image.

Eclipse Petroglyph at Horsethief Lake
Eclipse Petroglyph at Horsethief Lake
To me this petroglyph is obviously a total solar eclipse.

To my eye the image is clearly that of the solar corona surrounding the black shadow of the Moon against the Sun. The image is all the more striking to me personally… In 1979 I witnessed a total solar eclipse, my first, just a short distance from here, from the bluffs above Maryhill.

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A Blue Jet

Having an array of cameras on the summit of Mauna kea that capture images all night long has advantages. While the cameras are intended to allow the telescope operators to monitor the weather, they do catch other atmospheric phenomena.

In this case is it a powerful blue jet, a form of upper atmospheric lightning. While these sort of events had been reported for decades, mostly by aircraft pilots, they were only acknowledged by meteorologists after they were first photographed in 1989.

My friend Steve Cullen first noticed the jet in an image from one of the Gemini North CloudCams. It jets upwards from a strong thunderstorm cell passing north of the island, part of the remains of Hurricane Fernanda.

Unfortunately our Keck CloudCam is pointed just a little too west to have captured this event. The next night our camera captures several red sprites, but they are rather distant.

The various cameras capture sprites and jets with a fair regularity anytime there are strong thunderstorms around the islands. If a hurricane is anywhere in the vicinity it pays to check the archives. This jet is bar far the most impressive yet.

Enjoy the image…

A blue jet as seen from Mauna Kea on the night of 23July, 2017
A blue jet from a thunderstorm passing north of the island. Original image is a CloudCam image courtesy Gemini Observatory/AURA

Update: On Facebook we were having a discussion about how tall the jet was. I calculated the image scale of the camera, a Canon XTi with a 20mm lens, arriving at about 59 arcseconds per pixel. I also measured the jet as 840 pixels high (there is some extension of the upper part in a hard stretch of the image). Thus the jet is 13.74 degrees high, now all you need is distance to the cell.

Tom Polakis found a good satellite image from the night in question showing the storm about 210 miles away from the summit of Mauna Kea. This and a little trigonometry shows the jet rose about 51 miles above the top of the storm clouds!

4WD and Washboard on Mauna Kea

It has long been policy on the Mauna Kea summit road to use four wheel drive while ascending the mountain. One of the reasons given is to slow the formation of washboard, the annoying ripples that inevitably form on gravel roads.

Convoy
A convoy of observatory vehicles heads up the summit access road

On Mauna Kea an oft cited mantra is that the use of four wheel drive when ascending the mountain reduces the formation of washboard. I have always suspected this is a mountain myth with no substance. Where does this belief come from? Is there any real information on this?

The Manuals

There are a great many references that detail the practical details of maintaining gravel roads. Generations of highway engineers have spent a lot of time studying and writing about how to best maintain gravel roads at the least cost.

Washboard
Typical washboard on the Mauna Kea access road

The US Department of Transportation highway Administration has published a lengthy guide to the problems and solutions of gravel roads. This guide dedicates a dozen pages to the issue of corrugation or washboarding. While multiple factors in the formation and prevention of washboarding are discussed there is no mention of 4WD vehicles being a factor.

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Kelvin-Helmholtz Waves

When two bodies of fluid are moving in different directions interesting things happen at the boundary. The result is usually some sort of wave… Waves on the surface of the ocean or waves in the sky.

Waves on the sea surface are easy to see. Waves in the sky? Not so much. These waves are only betrayed if clouds form in the waves, revealing these structures.

Kelvin-Helmholtz Waves in the Saddle
Kelvin-Helmholtz Waves in the Saddle with Mauna Loa in the background. Photo by Joe Gargiulo, used with permission
This sort of wave is called a Kelvin-Helmholtz wave after Lord Kelvin and Hermann von Helmholtz who first investigated how these waves form. Yes this is the same Kelvin for whom the units of temperature are named. KH waves are visible all around us for those who know to look, from the surface of our ocean to the clouds of Jupiter, these characteristic swirling patterns are seen.

In the Saddle region over Mauna Kea and Mauna Loa, there are usually two air masses moving in different directions. Below the inversion level the tradewinds push westward. While above the inversion level, usually about 6-7,000ft, the upper air moves to the east. Where these two meet there are often KH waves, and occasionally some clouds to outline these fascinating structures.

The Opposition Effect

It was pretty obvious, an odd bright spot in the trees below that followed the helicopter. Having educated myself on quite a few optical phenomena I knew exactly what it was I was seeing, and made a point of taking a few photographs.

Opposition Effect
A bright spot in the Puna rainforest caused by the opposition effect
The mechanism for this bright spot is remarkably simple… No shadows.

Called the opposition surge, Seeliger effect or shadow hiding this simple optical phenomena occurs when looking at rough or irregular surfaces that are directly away from the light source, usually the Sun. On an irregular surface some parts will shadow other parts, resulting in an apparent darkening of the overall surface. When looking at that part of the surface directly away from the light source no shadows are seen, making that region appear brighter.

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