A Darker View

I know, I am late to this party. Not unusual, I do not often jump on the latest tech. I still use an iPhone 3GS, only three models back. It was, as usual, my wife who bequested this latest toy upon me. Without her I would be hopelessly out of date.

The camera is interesting to us as it comes with a standard waterproof housing good to scuba depths. The price was right, Deb picked it up as a Costco special.

Thus I attached it to the top of my usual rig to give it a try on a dive or two. As it turns out, it is a good thing I had my regular camera along, there are some issues with a stock GoPro underwater.

The first obvious issue is focus, as I had heard the camera will not focus properly underwater with the standard dome port. The solution to this is to get a flat port.

The more concerning issue is the burned out highlights visible in the video below. This is not unusual in a camera using a typical exposure algorithm designed for daylight above water. Underwater the red light is gone, absorbed by the water. This lack of red creates a tendency for the camera to overexpose the green or blue.

The usual solution is to set a slight under exposure in the scene using exposure compensation. However, the Hero 2 has no exposure compensation control. There are a couple possible solutions… Commonly available is a red filter for the flat port camera. Will this solve the burnouts? Another possibility lies in using a less saturated color profile as available in the new firmware.

While there were issues with the image, the sound seems pretty good for being in a case, much the same as what I hear when diving. The real test would be to dive with a few whales around to see how well it records whalesong. Alas, the humpbacks headed north a couple months ago. I miss the whalesong soundtrack on our dives. A pod of dolphins perhaps?

I plan to set up the GoPro as a stand alone camera and video rig for diving. Just the camera, an Ultralight handle and arm I have on-hand, plus a video light, which I also have on-hand. I just need to manufacture a tray for the setup, another hour in the machine shop. This should make a compact, lightweight dive or snorkeling camera rig.

I can think of a few other interesting uses for the camera, it has some nice timelapse facilities I need to test. Just the camera to use on the top of a boat. The camera does not do low light, just too small a sensor and lens. Still, there are quite a few things it should do well, a fun addition to the kit.

e Moon, Venus and Aldebaran

The Moon, Venus and Aldebaran join up for an evening conjunction

The three brightest planets are about to join up for an evening dance set. Currently Mercury is rising clear of the Sun’s glare into the evening sky. There it will join Venus and Jupiter for a conjunction that will continue, with various partners, for over a month. The three dancers will be well matched for brightness, with Mercury shining around -1 magnitude, Jupiter at -2, and Venus around -4 magnitude.

On the evening of May 24th Venus and Mercury will be about 2° apart with Jupiter 4° above. Closest approach of the three will occur the evening of May 26th with the trio forming a neat triangle about 2° on a side. On the 28th Venus and Jupiter will be just over 1° apart. During the first few days of June, the planet Jupiter will bow out of the dance, exiting the stage into the Sun’s glare. Venus and Mercury will join up one more time for a few days after June 17th, with a close approach on the 19th and 20th with about 2° separation between the two. When Mercury also heads into the sunset this dance will end during the last days of June.

On the 9th and 10th of June the Moon will run across the stage, a very thin crescent around 2% illuminated and 6° south of the planets.

Much of the dance will take place about 15° above the sunset, high enough to be nicely visible, low enough that the glow of sunset will provide a colorful backdrop to light the stage.

A very common fish, endemic to Hawaiian reefs, the pretty cleaner wrasse easily catches your attention with a brilliant neon color scheme. You see these fish nearly every time you get in the water. They are usually found in some cleft in the reef or above a prominent coral head working over another reef fish. They feed on parasites, mucous and dead skin of the other fish. The cleaning services offered by these small wrasse are so popular that there will often be several fish waiting their turn.

While cleaner wrasse are quite pretty they are also infuriatingly difficult to photograph. You can usually get close, they are not overly shy. The problem is that they never stop moving, swimming with an odd, jerky motion in the water. I have long since lost count of the number of blurred photos I have of this fish.

Cleaner Wrasse

A cleaner wrasse (Labroides phthirophagus) in an overhang filled with red sponges and coralline algae

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. Currently about 10° from the Sun it will rise higher each evening, reaching a maximum elongation of 24° on June 12th.

Mercury will join Venus and Jupiter in the sunset making for a series of planetary conjunctions over the coming month.

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.

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…

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.

Tako

A Hawaiian Day Octopus or He’e Mauli (Octopus cyanea) in reef shallows at Puakō

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

Our May meeting will take place tonight, Tuesday, May 14th, 7:00pm at Keck Observatory HQ in Waimea. This month we have local photographer Ethan Tweedie in to talk.