Author: Andrew

An electrical engineer, amateur astronomer, and diver, living and working on the island of Hawaiʻi.

Lahaina Noon

Living south of the Tropic of Cancer we get to experience an interesting phenomena that folks outside the tropics will not see. There are two days each year when the Sun passes directly overhead. In the islands this event is called Lahaina Noon.

Spring Lahaina Noon for 2013
Location  Date Time
Hilo May 18th 12:17pm
Waimea May 19th 12:20pm
Kahului May 24th 12:23pm
Honolulu May 26th 12:30pm
Lihue May 30th 12:36pm

 
Lahaina noon occurs twice each year as the Sun appears to move northwards with the spring and again as it moves southwards in the fall. For the islands of the Hawaiian archipelago the first day is between May 16th and May 31st. The second Lahaina Noon will be between July 10th and July 25th.

The date on which this event occurs each year depends on your exact latitude, the further north the later in the spring it will occur. Thus the day for Lahaina noon will vary by eight days from Hilo to Honolulu, and another five to Lihue. As you approach the Tropic of Cancer at 23°26’N Lahaina Noon will occur closer to the summer solstice. The date will also slip a little due to the out of sync nature of our seasons and our calendar. This is the reason we insert a leap year into the calendar every four years.

This year Lahaina Noon will occur on May 18th for residents living in Hilo, or May 26th for Honolulu. It is also important to remember that the Sun is not directly overhead at 12:00 exactly. As the islands lie west of the center of the time zone, true local noon occurs up to half an hour after 12:00.

Asteroid 1998 QE2 to Sail Past Earth

JPL press release…

On May 31, 2013, asteroid 1998 QE2 will sail serenely past Earth, getting no closer than about 3.6 million miles (5.8 million kilometers), or about 15 times the distance between Earth and the moon. And while QE2 is not of much interest to those astronomers and scientists on the lookout for hazardous asteroids, it is of interest to those who dabble in radar astronomy and have a 230-foot (70-meter) — or larger — radar telescope at their disposal.

Asteroid 1998 QE2 Orbit
The orbit for asteroid 1998 QE2 earth approach on 31 May 2013. Image credit: NASA/JPL-Caltech
“Asteroid 1998 QE2 will be an outstanding radar imaging target at Goldstone and Arecibo and we expect to obtain a series of high-resolution images that could reveal a wealth of surface features,” said radar astronomer Lance Benner, the principal investigator for the Goldstone radar observations from NASA’s Jet Propulsion Laboratory in Pasadena, Calif. “Whenever an asteroid approaches this closely, it provides an important scientific opportunity to study it in detail to understand its size, shape, rotation, surface features, and what they can tell us about its origin. We will also use new radar measurements of the asteroid’s distance and velocity to improve our calculation of its orbit and compute its motion farther into the future than we could otherwise.”

The closest approach of the asteroid occurs on May 31 at 1:59 p.m. Pacific (4:59 p.m. Eastern / 20:59 UTC). This is the closest approach the asteroid will make to Earth for at least the next two centuries. Asteroid 1998 QE2 was discovered on Aug. 19, 1998, by the Massachusetts Institute of Technology Lincoln Near Earth Asteroid Research (LINEAR) program near Socorro, New Mexico.

The asteroid, which is believed to be about 1.7 miles (2.7 kilometers) or nine Queen Elizabeth 2 ship-lengths in size, is not named after that 12-decked, transatlantic-crossing flagship for the Cunard Line. Instead, the name is assigned by the NASA-supported Minor Planet Center in Cambridge, Mass., which gives each newly discovered asteroid a provisional designation starting with the year of first detection, along with an alphanumeric code indicating the half-month it was discovered, and the sequence within that half-month.

Continue reading “Asteroid 1998 QE2 to Sail Past Earth”

Kepler Mission in Jeopardy Due to Mechanical Failure

Bad news today, the Kepler Spacecraft has suffered a mechanical failure. As feared, one more of the reaction wheels that keep the spacecraft stabilized has failed. Of the set of four reaction wheels two have now failed, at least three are required to continue the mission.

Kepler
Artist’s rendition of the Kepler Spacecraft in orbit around the Sun peering at a distant solar system, press release image from the NASA Kepler website
Keck and Kepler have been a potent team in finding and confirming hundreds of exoplanets. Kepler detects alien world through the transit technique, the very slight dimming of a star as a planet passes in front. Data from an instrument such as Keck’s HIRES spectrograph is required to confirm the find through the use of radial velocity data. Using the technique Kepler has discovered 130 extrasolar planets that are now confirmed. An amazing 2,700 possible planets are awaiting confirmation. Besides the discovery of exoplanets the Kepler data set has been a bonanza to astronomers looking for other phenomena. Magnitude data on more than 100,000 stars with unprecedented precision has allowed the discovery and study of a wide range of stellar phenomena.

Engineers will continue to see if the reaction wheel can be nursed back to some level of function in an effort to salvage the mission. The prognosis is not good, it is likely the Kepler mission has ended. In any case it will take astronomers years to learn what the massive haul of Kepler data can teach us and to work through the backlog of candidate planets. In a few years the spectacular success of Kepler will be followed up by TESS, the Transiting Exoplanet Survey Satellite, due for launch in 2017.

Space and Astronomy at the Kona Library

Planets, Stars, and How to Live on a Space Station

May 23rd Astronomy Program
Kailua Kona Library
3:30 PM to 4:30 PM

Allan Honey, a program engineer at Keck Observatory, will talk about the different distances in space between stars and planets. Allan’s son, Ben Honey, a flight controller for the International Space Station at the Johnson Space Center in Houston, will explain what happens when astronauts live and work in space. Allan Honey has worked at the Keck Observatory for more than 26 years, and Ben Honey grew up on the Big Island before leaving to study at Embry-Riddle Aeronautical University

Keck Lecture

Antennae Galaxies
The Antennae Galaxies, NGC4038 & 4039 as imaged by MOSFIRE, image credit Keck Observatory
Join the W. M. Keck Observatory for an evening of astronomy presented at the Kahilu Theater.

MOSFIRE is the newest and the most advanced astronomical instrument available today. Dr. Ian McLean from UCLA will describe some of the technical challenges developing and commissioning this multi-year, multi-million dollar instrument. He will also share early science results ranging from the discovery of ultra-cool, nearby substellar mass objects, to the detection of oxygen in young galaxies only 2 billion years after the Big Bang.

Wednesday, May 22, 2013
Show starts at 7 p.m.
Free and Open to the Public

Postcard from the Reef – Trumpetfish

Another very common species on Hawaiian reefs, one commonly seen by snorkelers and divers alike. The trumpetfish can be either bright yellow or silver with dark markings around the tail. Either way an interesting and handsome fish…

Trumpetfish
A bright yellow trumpetfish (Aulostomus chinensis) at Eel Cove

The Moon, Venus and Jupiter

The sunset is getting crowded. This evening will see a trio of the sky’s brightest objects low in the shades of sunset. Venus is still quite low, ony 10.3° from the Sun, shining brightly at -4 magnitude and rising higher each day. Well above Venus can be seen Jupiter, somewhat dimmer at -2 magnitude and 23° from the Sun.

In between the two a pretty crescent Moon is positioned, 4.4% illuminated and about 5° below Jupiter. Tomorrow night will see the Moon above and south of Jupiter with about 7° separation.

This is just the start of a sunset dance that will play out over the coming month. Stay tuned for Mercury to join Venus and Jupiter.