Transit of Mercury May 9, 2016

On May 9th, 2016 Mercury will transit the Sun. While transits of Mercury are not rare, they are not all that common either. The last transit was almost a decade ago in November of 2006. On average there are fourteen transits of Mercury each century or one every seven years. If you wish to observe one the situation is much better than transits of Venus which occur in pairs over a century apart.

This particular transit will favor observers in Europe and North America where the entire transit will be visible. Unfortunately for observers in the islands only the final three hours of the transit will be visible having begun well before local dawn. Sunrise will occur around 05:48 for the island of Hawaiʻi, with the transit ending at 08:42 in the morning.

Mercury Transit
Mercury transiting the face of the Sun, 6 Nov 2006
Mercury Transit May 9th, 2016
  UT (geo) HST HST (offset)
First Contact 11:12 01:12 –:–:–
Second Contact 11:15 01:15 –:–:–
Greatest 14:57 04:57 –:–:–
Third Contact 18:39 08:39 08:39:58
Fourth Contact 18:42 08:42 08:43:10
 

Source: NASA Eclipse website

 
The table at the right gives the transit geocentric UT and offset HST times. As our line of sight is shifted slightly from Hawaii there is a slight offset in the timing from our vantage point.

First contact is simply the first moment that the disk of Mercury begins to impinge on the disk of the Sun. Second contact will be the moment when Mercury is entirely in front of the Sun. Third and fourth contacts are a reverse of first and second with fourth contact as the end of the event.

Observing a planetary transit of the Sun requires proper eye protection. If you can not look safely, do not look! The Sun can cause permanent eye damage if viewed without proper protection. As Mercury is quite small some magnification will be useful in observing this event, a telescope of binoculars with a solar filter. A pinhole camera can be made out of things lying around in your kitchen that provides a very good image. Read my Guide to Safe Solar Viewing for a lot more information on viewing the Sun safely.

The next transit of Mercury will occur November 11, 2019 at 15:20UT (mid-transit). This next transit also favors Europe and eastern North America where the entire transit will be visible.

Mercury Appears in the Evening Sky

The planet Mercury is starting an evening apparition. The planet should become visible this week just above the fading glow of the setting Sun as a magnitude -1 object. The planet is moving about 1° further from the Sun and higher in the sunset each day, reaching a maximum elongation of 21° on May 6th.

Continue reading “Mercury Appears in the Evening Sky”

A Pop, a Puff of Smoke, and an Ominous Red Glow… Not Good

When powering up a nearly three decade old computer for the first time I should really have a video camera running…

The loud pop, and the stream of smoke issuing from the side vents was bad enough. It was the ominous orange glow seen for just a couple seconds from the same vent that really sent me the message…

Not good.

Compaq Portable III
A Compaq Portable III personal computer, circa 1987, photo courtesy Wikimedia Commons
I yanked the power cord as quickly as I could, then just sat there for a moment considering the implications of disaster. A Compaq Portable III, a design first marketed in 1987. A computer that runs DOS, predating the first versions of windows. This is the computer that holds the software that operates the Keck II dome.

Without this machine it will be very difficult to program the old PLC the dome runs on. I do have a replacement for that PLC controller running in my office, but I face the challenge of verifying the design, I would like to run the old software in the test setup to compare it to the new. I would also like to have a backup in case something goes wrong during the transition, a way of putting the old PLC back into the system and programming it.

Continue reading “A Pop, a Puff of Smoke, and an Ominous Red Glow… Not Good”

Reasons to Carry a Camera

I work at the summit of a nearly 14,000ft mountain that sits atop a pretty tropical island. That alone is good enough reason to carry a camera at all times. You never know when you will need that camera, beauty appears when you least expect it.

Dome Motor Controller
The control wiring for a Keck 1 dome VFD motor controller
There are other reasons to carry a camera in my life. I often use the camera to document my work. There is a camera, the little EOS-M, in my backpack alongside the rest of my tools. Wire cutters, screwdrivers, allen wrenches, a multimeter, all the useful tools I need every day, along with a camera, memory cards and spare batteries.

The advent of digital cameras where the cost of each photo is negligible has made this possible. This would not have been practical in the days of film. Yes, I remember those days, counting out every frame of a 36 exposure roll, deciding if the shot was worth it. In this digital age I usually have a dedicated camera along and never worry about shooting. If that camera is out of reach there is always the iPhone in my pocket.

The equipment I work on is often unique, there may be only one copy in the world. Two if we have one installed on both Keck 1 and Keck 2. The documentation can be of varying quality, some is good, some is abysmal, some is just plain wrong. Some of this gear was professionally built by engineers, some of it was built by graduate students who would never need to fix it years later.

Continue reading “Reasons to Carry a Camera”

Pukiawe

Pukiawe
Pukiawe (Styphelia tameiameiae) on the slopes of Mauna Kea
An attractive bush seen commonly on Mauna Kea, this shrub is common across the dry cinder slopes and recent lava flows. Styphelia tameiameiae is a member of the family Epacridaceae the plant is found throughout the Hawaiian islands and is endemic to Hawaii and the Marquesas.

Pukiawe
Pukiawe (Styphelia tameiameiae) on the slopes of Mauna Kea
As you ascend the mountain pukiawe is one of the last plants you will see, growing at elevations up to 10,000ft. Along the Mauna Kea access road it is one of the most common plants dotting the mountainside. Large isolated bushes scattered widely among the gravel switchbacks above Hale Pōhaku.

Small, upright leaved are densely spaced on the branches. The small (5mm or 1/4in) red fruits are not edible. The leaves of the plant were used for medicinal purposes by the ancient Hawaiians.