
Author: Andrew
Star Trail Photography
Taking star trails is one of the easiest forms of nighttime photography. it requires less equipment than full out astrophotography, only a camera that can take a long exposure and a tripod. In a pinch you can do without the tripod.

For a number of reasons taking one very long exposure is a problem with digital cameras. Without getting into a technical discussion of noise, dark current and hot pixels we will simply advise taking short exposures. You can always try a twenty minute or half hour exposure and see for yourself. Thus the technique is to take a series of short exposures, usually one to five minutes long, and add these together in processing. By taking a series of short exposures, the final exposure length is limited only by the camera battery or the arrival of dawn.
If the camera is sensitive enough, and you have a fast lens, you might try starscape photography, where the stars are not trailed by the motion of the Earth. In contrast, star trail photography can be done by almost any camera that can take a long exposure. The difference is in the length of the exposures, long versus short, star trail or starscape.
New Moon

An annular solar eclipse will be visible from Australia, Antarctica and across the southern Indian Ocean today. This is a somewhat odd eclipse as the center of the Moon’s shadow misses the Earth entirely. The eclipse will be quite short and visible over a limited geographic area.
Hāpuʻu
Postcard from the Summit – Relays
Postcard from Hawai’i – Kailua Bay
Mercury at Superior Conjunction
Today Mercury passes through superior conjunction, passing behind the Sun as seen from the Earth. The planet will appear in the sunset in ten days or so, reaching maximum elongation on May 24th.
Diving the Naked Lady
A different sort of dive. There are few wrecks to dive on the Big Island, the Naked Lady is one of the few. An Easter Sunday morning spent out on the water, enjoying a beautiful day. As we came back across Kailua Bay from diving at Casa Cave we decided to dive the wreck as our second dive of the day.

It is 110 feet to the sand where the Naked Lady lies on the bottom. This is a short dive, at this depth our bottom time is limited to less than 20 minutes due to nitrogen absorption. Even with the safety stops on ascent the entire dive was about half an hour, I surfaced with over 1200psi of air left in the tank. Considering I often last over an hour with a 80cft tank this was a short dive indeed.
Deb and I did not bother with the mooring line as we dropped to the bottom. The water was clear enough we could see the wreck on the sand 100ft below. With no current we simply dropped, in the clear water this was a surreal, slow motion free-fall. Seeing the sand approaching I did not bother to trim buoyancy, but allowed myself to hit the sand a few feet from the hull. The gauge read 109ft as I knelt on the bottom. I took a couple photos, trimmed for neutral buoyancy and started exploring.

Aside from a few colonies of cauliflower coral on the wreck itself there is no coral visible, simply a flat plain of sand that stretches in all directions. A swarm of fish surround the wreck, snappers and dasyllus the most numerous. Oddly there are numerous rough spined urchins on and around the hull.
There is little sign of life away from the wreck, the sand seems sterile from a distance. Upon closer examination even this sand desert teems with life. Burrows and tracks betray numerous residents. I take a few photos of a colorful goby I have yet to identify, it does not appear in the usual guidebooks.
The Atlantis Submarine that gives tourists a ride in Kailua Bay often tour the Naked Lady. The submarine was present when we arrived at the mooring, but had moved off by the time we dropped to the wreck. It would have been fun to wave at the tourists.

The location results in a different dive profile as well. On this island we usually dive deep and then spend the rest of the dive slowly working our way back up the reef, ending in shallow water. A slow ascent eliminates the required safety stops used in recreational diving. Here there is no sloping reef, simply a drop to the bottom. Time to remember those safety stops and monitor the dive computer closely. This ascent required two stops, one at 50′ and another at 15′ to allow the nitrogen to transpire out of our tissues.
With two dives done it had been a great day and we were ready for more. Alas we had a pile of empty tanks and a distinct lack of full. Nothing left but a return to harbor, clean up the boat and an early dinner at the fish market. A great Easter Sunday, far more fun than sitting in church.
The Moon and Venus
Tomorrow morning, April 25th, will see a brilliant Venus paired with a crescent Moon. Look for the pair to rise about 03:41HST to be 30° above the horizon at sunrise. A 15% illuminated Moon will be a nice match for Venus shining brilliantly at -4.1 magnitude. Separation will be about 4°.
The following morning, April 26th, will see the Moon much closer to the horizon, over 11° west of the planet.
Vintage Film of Kilauea
A glimpse of the activity at Kilauea almost a century ago…
Thanks to local blogger Damon Tucker for the link!


