Category: Astronomy

Exploring the cosmos

Winter Solstice

Winter solstice occurs today at 01:12HST. Today the Sun will occupy the most southerly position in the sky of the year. The term solstice comes from the latin terms Sol (the Sun) and sistere (to stand still). On this day the Sun seems to stand still as it stops moving southwards each day and begins move to the north. This is the first day of winter as marked by many cultures in the northern hemisphere.

2012 Solstices and Equinoxes
  UT HST
Perihelion Jan 5 03:59UT Jan 4 17:59HST
Spring Equinox Mar 20 05:14UT Mar 19 19:14HST
Summer Solstice Jun 20 23:09UT Jun 20 13:09HST
Apehelion Jul 4 23:59UT Jul 4 13:59HST
Fall Equinox Sep 22 14:49UT Sep 22 04:49HST
Winter Solstice Dec 21 11:12UT Dec 21 01:12HST
 
Source: USNO Data Services Website and the NASA Sky Calendar

 

Working the Weather

One of the little side jobs I have gotten assigned at Keck is updating the weather station. This involves replacing all of the weather monitoring equipment that allows the operators to keep an eye on conditions around the telescopes. This gear is absolutely critical, giving the operators the data they need to protect our equipment, including the irreplaceable mirrors.

Keck Weather Mast
The weather mast atop the Keck observatory building
As a side job it has been fun. A simple job that can be completed with a minimum of complications and the usual folderol that surrounds larger engineering projects. Just come up with a plan, put some numbers on the plan, buy the gear and install it. As budget has allowed I have worked my way through the plan, replacing bits of gear one item at a time.

It has been fun to learn about measuring temperature, humidity, dew point and more. It seems so simple at first, but the complications of getting a good reading are subtle. Passive instrument shelters, active ventilation, instrument positioning, calibration and more. Issues that can make a good instrument give bad data.

Barometric Sensor
A barometric sensor installed in the Keck weather mast
Likewise the severity of the weather at the 13,600ft elevation of the observatory is a real challenge. How do you get a good reading in 70mph blowing snow? What do you do about 8 inches of ice that has formed over every vertical surface. That one was a challenge, the first shelter I put up for the temperature and humidity partially collapsed under the weight of the ice on the sensor cables.

Last week I installed a new barometric sensor. This was the last part of the existing weather instrument suite that needed to be replaced. I got lucky, it was a great day on the summit, sunny with just a modest breeze. Just the day to spend a couple hours hanging off the weather mast in a climbing harness rewiring a junction box for the new cables. A few holes to drill, a few bolts, a couple cables… done!

My next item is to install an anemometer. We have not had an operational anemometer in many years and our observing staff has made it abundantly clear that they want an anemometer. Not that this one will be easy, it is a bit of a challenge to get a decent wind reading anywhere near a 100ft diameter dome. This challenge will be a bit more involved, and involve some good engineering fun. Time to learn about measuring wind-speed and how to do it right. Looking forward to the next part of the plan!

Found: One Planet Orbiting Sun-like Star. Only Twelve Light Years Away

W. M. Keck Observatory press release…

An international team of astronomers using the W. M. Keck Observatory and other telescopes, has discovered that Tau Ceti, one of the closest and most Sun-like stars, may host five planets – with one in the elusive ‘Goldilocks Zone’.

Tau Ceti
Artists impression of the Tau Ceti System. Credit: J. Pinfield for the RoPACS network
At a distance of twelve light years and visible with the naked eye in the December evening sky, Tau Ceti is the closest single star that has the same spectral classification as our Sun. Its five planets are estimated to have masses between two and six times the mass of the Earth – making it the lowest-mass planetary system yet detected. One of the planets lies in the star’s habitable zone – the so-called Goldilocks Zone with it’s ‘just right’ temperatures for supporting liquid water – and has a mass around five times that of Earth, making it the smallest planet found to be orbiting in the habitable zone of any Sun-like star.

The international team of astronomers, from the UK, Chile, the USA, and Australia, combined more than 6,000 observations from three different instruments, including HIRES on the Keck I telescope. Using new techniques, the team has found a method to detect signals half the size previously thought possible. This greatly improves the sensitivity of searches for small planets and suggests that Tau Ceti is not a lone star but has a planetary system.

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Science Fair Season

School science fair season is here! As an engineer, it is wonderful to see school kids doing science and engineering tasks. I enjoy going to see what the students have come up with and giving a little of my time to support science and engineering education.

Science Fair
Students from Parker School participate in science fair
In the past two weeks I have served as a judge for two science fairs, Parker School and Kanu o ka ‘Āina. Parker is a private school in Waimea with a well deserved reputation for excellence. Kanu is a charter school with a heavy emphasis on Hawaiian culture. Both schools make a special effort with science fairs, expecting their students to participate and go on to the county and state wide competitions.

As usual, the projects are quite the mix. Some projects are simply the usual stuff, variations on the standard projects one can find posted to the internet, standard fodder for science fairs nationwide. Not that I totally disapprove of these common projects, students can gain valuable experience when performing any good experiment, even one done many times before. It is all in the execution.

One difference you really find here in Hawai’i, is a heavy emphasis on Hawaiian culture and special problems unique to the islands. This leads to unique experiments that address local issues. Propagation of native plants, alternative energy, permaculture, issues that have a direct connection with island life. Some student explore aspects of native Hawaiian technology. I was particularly impressed by experiments in traditional dye mordants examining the effectiveness and permanency of various mordants with tumeric dye and cotton cloth.

The results are likewise quite the mixture. Experiments that result in good success, to others that do not fair so well. Looking at a growth chart with all zeros in the data table I was forced to ask… “did the plants just not grow?” …”They all died.” Still, failures can be just as good learning experiences as success, sometimes better. I am always impressed by a student who admits failure and can explain what went wrong.

Some of the students I graded will go on to the regional competitions, I expect some will do quite well. Good luck!

Visiting the Summit of Mauna Kea

Visiting the summit of Mauna Kea is high on many visitor’s to-do list when coming to the island. The summit region is spectacularly beautiful, even after six years of visiting several times a week I still find it so. My habit is to drive, or to ride shotgun in order to enjoy the view. I keep a camera at hand, ready for the inevitable situations where beautiful is transformed to spectacular with a well placed cloud or shaft of sunlight.

Summit Visitors await Sunset
The usual crowd of summit visitors await sunset along the ridge between the Gemini and CFHT telescopes
Any visit to the summit starts by stopping in at the Mauna Kea Visitor Information Center. Located at 9,200ft the center is found at the end of the paved road. The folks here are responsible for providing visitor information and helping you out if you get into trouble, a service provided by the observatories through Mauna Kea Support Services. This includes the Mauna Kea Rangers who patrol the mountain, providing information, advice and assistance to visitors. Also found at “The VIS” are bathrooms, a gift shop, and the evening star gazing program.
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