Cup Coral
Author: Andrew
An electrical engineer, amateur astronomer, and diver, living and working on the island of Hawaiʻi.
Postcard from the Reef – Fuchsia Flatworm
Jupiter Exits the Evening Sky
Jupiter is quickly sliding into the sunset heading for superior conjunction on June 19th. This evening the planet will be 10° above the setting Sun, in the next few days it will disappear into the glare. Look for Jupiter to reappear in the dawn during the first week of July.
Exploding Glass: Prince Rupert’s Drop
As anyone who has worked with glass knows, the material is fascinating. Glass is fragile, yet it can be extraordinarily strong. This is a seeming contradiction, but one that makes sense if you start to understand what makes glass crack.
Via Phil at Bad Astronomy, a truly awesome video on Prince Rupert’s Drop, a simple construct of glass that exhibits the strength and weakness of glass in a very visual way.
Science is cool!
Comet C/2011 L4 PanSTARRS
Well past perihelion comet C/2011 L4 continues to put on an impressive show. Amateur sky-watchers have been enjoying the impressive anti-tail reaching out a few degrees from the coma. True, you may need a telescope or at least good binoculars to see the comet. It may be dimming, but still worth the effort to observe.
The iOptron ZEQ25
I had been looking to acquire another astrophoto toy. The desire is for a small, portable astrophoto setup. Yes, I am aware that the words “portable” and “astrophoto” do not really belong in the same sentence, all things are relative.
Thus I have decided on the new iOptron ZEQ25. It is a new design, with some radical differences from the more traditional German equatorial mounts.
The mount is pretty small, a mere 10 pounds of steel and aluminum. Compact enough to be packed into a suitcase for air travel. Performance sufficient to do wide field astrophotography with focal lengths up to 1000mm and a DLSR camera. Perfect for use with either my TV-76 or AT6RC. Unlike my old Losmady G-11 it features a modern GOTO system and can be run from the computer.
I ordered the mount from the good folks at OPT. It was not yet listed in the website catalog, but a phone call confirmed they were expecting delivery of three mounts shortly. I put down my deposit. A week later I had confirmation that the mount had been received and was ready for shipment to Hawaiʻi as promised.
Mercury, Venus and Jupiter
This evening will see a line of bright planets in the sunset. Easiest to spot will be the brilliant Venus, shining at -4 magnitude and 15° above the setting Sun. 4°30′ below Venus will be Jupiter, quite low in the sunset, but bright enough to spot at -2 magnitude. 4°16′ above Venus will be Mercury, notably dimmer at -0.2 magnitude. The three will form an almost perfect line of bright objects in the glow of sunset, it should be a nice sight.
Postcard from the Reef – Brown Booby
Three Hours on Two Tanks
I have had a few dives over 90 minutes, an hour and a half, on a standard 80 cubic foot aluminum tank. This time I managed two back to back dives totaling nearly three hours on two tanks. Not bad for air consumption! Admittedly I was moving slow, doing photography, on the other hand neither dive was all that shallow, averaging 30ft with deeper excursions.
Kua Bay is the last public day use mooring north of Kona for a long distance, the next buoys are at Anemoʻohalu Bay, almost 10 miles further north. The mooring is adjacent to the popular Maniniʻowali Beach, a beautiful crescent of sand that is well loved and heavily used. A prominent finger of coral juts out from the shore north of the beach, creating a nice 20ft wall to explore.
I spent the entire dive poking along this wall, looking for small invertebrates. I was rewarded by an assortment of nudis and flatworms. Most were species I had seen before. One flatworm was something different, a species I am still trying to identify.
I signal to him, making a shark symbol, a flat hand held sideways to the forehead, that gets his attention. I lead him under a ledge a few feet away, where there is indeed a white tip shark hanging out. When we surface a few minutes later he sums up the encounter… “That is the biggest white tip I have ever seen!” Yeah, it was pretty big. Living up to the scientific name as well, Triaenodon obesus, a well fed shark, a little fat even.
After washing up the boat we head into Bite Me for dinner and to talk story. We thumb though the photos of the day reviewing all we had seen. It was an excellent day diving. The water conditions were notably better than a month ago. Summer is arriving, the swell settling down, bringing clearer water conditions. Looking forward to a summer of more diving!
Goldring Surgeonfish
