Today’s Astronomy Picture of the Day features a view of Mauna Kea’s shadow on the sky, just at the tail end of last week’s lunar eclipse:

Mauna Kea Shadow from APOD (photo by Alex Mukensnable)

I couldn’t help but be reminded of our visit to the summit in April 2005, just at sunset, when I took this similar (but decidedly less cool) photo:

Atmospheric Optics explains why most mountains’ shadows look triangular when viewed from their summits.

Here’s our first view of the island of Hawai‘i, as our plane approached on Sunday morning, April 3. Snow-capped Mauna Kea is rising out of the clouds, with Mauna Loa behind it.

View of Mauna Kea from the plane

A week later, we spent Sunday evening waiting for our flight out of Kona Airport. (After a disastrous experience at LAX in which we arrived 2 hours ahead and got to the gate with maybe 15 minutes to spare, we showed up early for the flight home. But Kona’s much smaller and better organized, so it took us maybe 15 minutes to check in. There wasn’t even a line to go through security!)

Kona airport at night

I hope you’ve enjoyed this series on our Hawaiian vacation. I’m sorry it took so long to finish it, but hey, I managed (just barely) to beat the 6-month marker!

Years ago, I put the Niven/Pournelle novel Footfall in my to-read box. I finally started reading it today. After a prologue that takes place mostly at the press conference for the 1980 Voyager 1 encounter with Saturn, the first chapter opens (years later) with a drive up Hawaii’s Kona coast and inland to the observatories at Mauna Kea.

Now there’s timing. If I’d read it when I first picked it up, I could only imagine that sequence. Now I know exactly what it looks like. Well, aside from the fact that there are twice as many observatories now as there were when the book was written.

Up at the visitor’s center for the Mauna Kea observatories, there’s a sign that says, “Beware of Invisible Cows.” It was dark when we were there, and I tried to get this picture without using the flash since there were people with portable telescopes ten feet away, so it’s really blurry:

The actual invisible cows sign (blurry)

Fortunately someone in charge recognized the humor value, and the visitor’s center sells bumper stickers:

Beware of Invisible Cows
Why invisible cows?  It's dark and foggy.

Of course, it turns out other people, visiting during the day, have snapped better pictures of the sign.

Note: Our visit to Mauna Kea was on Saturday, April 9, 2005.

And now for something completely different: Hawaiian snow. On our second-to-last day in Hawaii, we took a tour up to the summit of Mauna Kea, the highest mountain in the state at 13,796 feet. And even in early April, they still had snow at the summit.

Hawaiian Snow

We caught a somewhat hazy view of it from the west, in the Kohala area, but our best view of the mountain actually came the day after the tour, on our drive out to Akaka Falls. We’re probably due east of the mountain here:

Mauna Kea seen from the road to Akaka Falls

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