Three Dives on a Holiday Weekend

We managed three dives last weekend. It was a holiday weekend, Kamehameha Day, that helped. But still, we average a couple dives a month, three dives in a weekend was a bit unusual. We dove with some friends at Pukao on Saturday. Then two more on the following Monday. This was conservative, a few of the guys dove on Sunday too!

Diver Down
Diver Mark Devenot cruising the reef at Hoover’s Towers north of Honokohau
Monday’s diving was with Dennis. Again he invited us out on his boat. The Aqua Safari is quite comfortable, a 42′ cabin cruiser outfitted for diving. There are plenty of tank racks, a big swim deck and a very nice ladder. Dennis is quick to point out one of the best features… A warm fresh water shower on the swim deck! Which, I have to admit, is rather nice.

Thus, Monday morning saw us packing up the dive gear, a cooler with drinks and sandwich makings for everyone, and heading for Honokohau. There Deb and I joined Dennis and Mark for a very nice day diving.

We have been diving a lot in the NELHA area lately, I expect we will be diving some more there. It is some spectacular diving in the area. A rich reef sloping out to a steep drop-off that descends far beyond scuba depths. You look into the deep blue and know that somewhere down there is the abyssal plain, 8,000 feet below.

As usual I had my face in the coral, in and out of every crevice or small cave I came across. This is a great way to find the little stuff I love to photograph, but you can miss the big stuff… A series a sharp clangs gets my attention, the sound of Mark’s tank banger. I pull myself out of an alcove and swim over the large coral outcropping just in time to see a ten foot manta sweep by! The manta was just beyond the reef drop-off, against the deep blue of open water.

The find of the day was a Spanish Dancer, the largest nudibranch found in the islands. I do mean large, while most nudi’s I locate are an inch or two long, this fellow was the size of a dinner plate. Dancers have another feature… They Dance! Actually a form of swimming through undulating the body. I flushed him out of a crevice in the cave and the nudi proceeded to dance for us, everyone got a good look. After a few photos, actually quite a few photos, I carefully shepherded the pretty fellow back into the crevice I found him in.

No dives this weekend, I was on call. But we are already planning another outing next weekend. Summer diving season is here, bringing calm and clear water to the Kona side. The crew is ready to go, discussing where we will dive next.

Venus and the Hyades

As Venus approaches maximum elongation it will pass through the Hyades star cluster. Because Venus reaches it maximum western excursion on July 1st the planet will sweep out an arc that runs just inside the V-shape of the cluster. Thus the planet will remain within the main body of the cluster for the next 20 days.

Today the planet is only 26′ from εTau at one corner of the V-shaped cluster. On July 8th the planet will pass about 1° from Aldebaran as it exits the cluster at the other corner of the V.

Postcard from the Universe – Galactic Center

The last time out I fitted a camera ball mount to the counterweight shaft of the Losmandy mount. This allowed me to shoot an additional camera at the same time, along with the camera attached to the telescope. The second camera can be aimed at a different target completely. With a relatively wide angle lens, tracking errors become insignificant.

With the center of the Milky Way high overhead it made an obvious first target to test this wide-field setup. The results are quite nice, a series of one minute exposures reveal the star clouds in fine detail. The camera for this run was the Canon 60D, as the 20Da was shooting the Lagoon at the time. I need to swap places and try the shot again with the 20Da to see what the Hα sensitivity reveals, capturing more of the nebulae that is mingled with the stars.

The lens was an older Nikon 50mm f/1.8 stopped down to f/2.8, nice round star images right into the corners of the frame. Yes, a Nikon lens mounted to a Canon camera, you can do that. A very nice lens, I will be using it again for this work.

Galactic Center
The galactic center region on the Sagittarius-Scorpius border

Postcard from the Reef – Hydroid Stings

This is not a case of “I wish you were here”, but rather another lesson in the many hazards of diving.

Hydroid Stings
The welts left behind by hydroid stings across a forearm one day after the injury

I know when I got hit, a series of pricks down my left forearm. I didn’t even react, I was concentrating on the photo. I continued to brace myself against the surge by using the rocks of the cave floor. Those rocks were home to some little critters that had an issue with the disturbance I was creating… Hydroids.

Through the rest of the dive my arm continued to sting, discomfort that persisted but was not really all that bad. I took no action other than noting that I had gotten hit. It wasn’t until the next day that I realized that the stings were not going to go away quickly. I had a series of red welts across my forearm, and they itched. Time to break out the hydrocortisone cream. A week later the welts have faded and shrunk to pinpoints, no longer itch, but are still there.

Hydroids
An unidentified hydroid hanging off a lobe coral (Porites lobata) Kohala Coast at about 70ft
The angry red welts did attract comment all week, they were rather noticable. I have had to explain what hydroids are a number of times. These small relatives of jellyfish posses the same defensive armament, stinging cells called nematocysts. As soon as you mention jelly stings the stories come out, most everyone on this tropical island has gotten stung at some point.

Friday evening we stopped into the shop of Kohala Divers for a bit. There were a few folks we know in the shop as they were having an open house. As I chatted with Lina Preskitt, a local marine biologist, I mentioned the stings, showing her my forearm. She raised her forearm to display a very similar set of red welts on her left arm! We laughed as we looked at a mirror of almost identical stings.

This is the second time I have been seriously stung by hydroids. Will it stop me from diving? Not at all. Perhaps be a bit more careful when mucking about on a cave floor.

The Moon, Venus and Jupiter

A nice trio will grace the dawn tomorrow, the morning of June 17th. Three bright objects will be visible just before sunrise. A brilliant Venus will be 14° above the horizon at sunrise. Above Venus will be a very thin crescent Moon, only 4% illuminated, will be 4° above Venus. About 8° above Venus will be Jupiter, shining brightly at -2.0 magnitude. Thus Jupiter will be the first to rise, at 04:02HST. Sunrise will occur about 05:43, leaving plenty of time to enjoy this bright conjunction.

Employment Opportunity at Keck – Machinist

W. M. Keck Observatory position announcement…

Senior Machinist-Infrastructure Technician

The W.M. Keck Observatory operates two of the world’s largest and most scientifically productive optical/infrared telescopes located on the summit of Mauna Kea on the Big Island of Hawaii. A highly capable and motivated staff operates, maintains and develops the complex telescope systems and infrastructure on the summit. We seek a Senior Machinist-Infrastructure Technician to join this high-caliber team.

This position is responsible for conventional and CNC machining of mechanical parts; interpreting complex mechanical fabrication drawings; and performing mechanical fabrication, assembly, adjustment and troubleshooting of precision mechanisms. In addition, this position will participate in maintenance of the summit infrastructure, including repairs of mechanical systems and preventative maintenance.

Minimum requirements are: Knowledge of materials, their properties, and suitability in different mechanical applications; five years of experience in an industrial environment with proven capability for installation, maintenance, and troubleshooting of mechanical systems; and eight years of experience as an industrial machinist building high precision parts.

Commitment to WMKO’s core values, working well with others, and the ability to handle multiple tasks and priorities within a fast paced environment are all essential. Additional information about WMKO and this position may be found on our website at www.keckobservatory.org/about/employment

This position requires you to submit your resume on-line at: http://keckobservatory.iapplicants.com/ViewJob-319065.html with your cover letter that states why you are uniquely qualified for the position.

EEO Employer

Postcard from the Universe – Lagoon

Another product of this last new Moon star party at the MKVIS. An easy target, suited to checking the performance of the new setup. As usual, click on the image to view the larger size…

The Lagoon
The Lagoon Nebula, NGC6523, in Sagittarius, 11 x 8min exposures, Canon 20Da and AT6RC

Postcard from the Reef – Keferstien’s Sea Cucumber

As I have discussed before, there are some weird critters on the reef. Some of the more alien appearing creatures are the sea cucumbers of the family Synaptidae, the thin-walled sea cucumbers. These look like large worms, moving across the reef by expanding and contracting their bodies. At the front end are a set of feeding tentacles, sweeping out in slow motion to move food to the mouth at the center. The body is flaccid, supported and given shape through an internal hydraulic system.

The small brown Keferstein’s sea cucumber is surprising sticky, with small hook-like spicules on its outer skin. It sticks readily to dive gear, twice now I have seen these critters stuck to a diver without the diver knowing. Carefully peeling them off they make a nice photographic subject before allowing these normally nocturnal critters to escape back into a crevice in the coral.

Keferstein's Sea Cucumber
Keferstein's Sea Cucumber (Polyplectana kefersteini) at 30ft, Puako

Venus Appears in the Dawn

This week Venus will appear in the dawn sky. Today the planet will be over 10° from the Sun at dawn. This will increase over a degree each day as Venus climbs higher into the dawn sky. Maximum elongation will occur on August 14th.

A few nice conjunctions will occur with both Jupiter and the Moon over the coming weeks. Stay tuned to Darker View for postings that will keep you up to date.