Postcard from the Reef – Blacklip Butterflyfish
Author: Andrew
An electrical engineer, amateur astronomer, and diver, living and working on the island of Hawaiʻi.
The Moon and Saturn
Tomorrow morning will find a nice crescent Moon near Saturn. The Moon will be 33% illuminated and about 5° away from the ringed planet shining at 0.6 magnitude. The pair will rise about 1:40HST and be high in the sky by dawn.
Looking Ahead to a Starry 2013
I am a bit behind in entry of all the significant astronomical events for 2013. Never fear! Everything important has been entered for January, so I am still ahead of the posting schedule! A few more evenings of blogging and I will have the whole year done.
While C/2011 L4 PanSTARRS is a good comet, comet C/2012 S1 ISON is likely to be a great comet. This comet will pass incredibly close to the Sun and reasonably close to the Earth. If we get lucky, and luck is a significant factor with comets, this could be the comet of a lifetime. Predictions for this comet indicate a possible magnitude well into the negative numbers during November and December. These sort of numbers indicate the comet may be visible in the daytime, and spectacular after sunset. Unlike comet C2006 P1 McNaught in early 2007, this comet will favor viewers in the northern hemisphere!
No great eclipses this year. There are no total lunar eclipses to be seen anywhere, just a partial and two minor penumbrals. An annular solar eclipse visible in the South Pacific that will be visible as a modest partial solar eclipse here in Hawai’i. A hybrid solar eclipse will be visible across the Atlantic and central Africa.
Meteor showers are a mixed situation for the year, some good news, some bad. We will be able to observe the Persieds in a dark sky after the setting of a waxing crescent Moon. The Leonids will occur during full Moon, but are not predicted to be great this year. The Geminids also occur during a full Moon, damping this reliable shower.
2013 will be a great year for watching the sky. Stay tuned to Darker View for alerts on any significant event occurring overhead.
A Vast Rotating Disk of Dwarf Galaxies Surrounding the Andromeda Galaxy
W. M. Keck Observatory press release…
Astronomers using the Canada-France-Hawaii and W. M. Keck Observatory telescopes on the summit of Mauna Kea, Hawaii have been amazed to find a group of dwarf galaxies moving in unison in the vicinity of the Andromeda Galaxy. The structure of these small galaxies lies in a plane, analogous to the planets of the Solar System. Unexpectedly, they orbit the much larger Andromeda galaxy en masse, presenting a serious challenge to our ideas for the formation and evolution of all galaxies.
The findings are being reported on the cover the upcoming issue of the journal, Nature.
While Persian astronomers were the first to catalogue the Andromeda galaxy, only in the last five years that we have studied in exquisite detail the most distant suburbs of the Andromeda galaxy via the Pan-Andromeda Archaeological Survey (PAndAS), undertaken with the Canada-France-Hawaii Telescope and measured with the Keck Observatory, providing our first panoramic view of our closest large companion in the cosmos.
The study culminates many years of effort by an international team of scientists who have discovered a large number of the satellite galaxies, developed new techniques to measure their distances, and have used the Keck Observatory with colleagues to measure their radial velocities, or Doppler shifts (the speed of the galaxy relative to the Sun). While earlier work had hinted at the existence of this structure, the new study has demonstrated its existence to a high level of statistical confidence (99.998%).
Continue reading “A Vast Rotating Disk of Dwarf Galaxies Surrounding the Andromeda Galaxy”
Postcard from Hawai’i – Dried Bananas
We are attempting to deal with our banana surplus issue.
A bunch of bananas is too much fruit for us to use in the few days before they spoil. A single bunch can yield 50 to 60 bananas. We snack on bananas, we make smoothies, we slice bananas onto our morning cereal, it is still too many bananas. Our standard answer to avoid waste is to give away much of the fruit. Apple bananas are quite popular and quickly accepted when given away to neighbors an co-workers.
This time we are trying dried bananas using a recently purchased food dehydrator. A bit of an experiment, I have never done this before. I dimly remember my mother drying bananas when I was a kid, I do remember the results being pretty good.
He’e
Perihelion
Today the Earth is closest to the Sun, a point called perihelion. We will be about 147,099,000km (91,403,000miles) from the Sun. Compare this to the 152,096,000km (94,508,000miles) we will be at aphelion on July 4th, a difference of about 4,996,000km (3,104,000miles) occurs throughout one orbit.
It may seem odd that we are actually at the closest for the middle of northern winter, you just have to remember that proximity to the Sun is not the cause of the seasons. The seasons are caused by the axial tilt of the Earth, creating short and long days throughout the year, with a resulting change in the angle and intensity of the sunlight.
| 2013 Solstices and Equinoxes | ||||
|---|---|---|---|---|
| UT | HST | |||
| Perihelion | Jan 2 | 00:59UT | Jan 1 | 14:59HST |
| Spring Equinox | Mar 20 | 11:02UT | Mar 20 | 01:02HST |
| Summer Solstice | Jun 21 | 05:04UT | Jun 20 | 19:04HST |
| Apehelion | Jul 5 | 18:59UT | Jul 5 | 08:59HST |
| Fall Equinox | Sep 22 | 20:44UT | Sep 22 | 10:44HST |
| Winter Solstice | Dec 21 | 17:11UT | Dec 21 | 07:11HST |
| Source: NASA Sky Calendar | ||||
Darker View’s Top Posts of 2012
Looking through the site statistics is an interesting exercise. I get a chance to see what people are reading. The vast majority of readers do not write comments, the stats are the best tool for feedback I have. Perusing the stats is also an realization of one’s own vanity, a necessary motivation for all writers, not just bloggers.
Site traffic has taken a large hit with the transfer to the WordPress platform. I expected this, there would inevitably be loss of links and search engine traffic with the changeover. This has begun to recover, but very slowly. There have been 55 thousand views of the Darker View blog in 2012. Overall there were 66 thousand views of the entire site for the year, not just the WordPress material. This compares to 91 thousand visitors in 2011, about two-thirds of pre-changeover traffic. Total traffic to Darker View since inception in 2007 is now over 288 thousand visitors.
2012 in Photos
For your viewing pleasure, here are some of the best photos from Darker View assembled into a gallery. New Year is a time for reviewing the year past. I have enjoyed the last year, with the photos to prove it. I hope that 2013 brings you the chance to collect your own gallery of photos and memories.
Christmas Eve Diving
What else would I do on a Christmas Eve? Go shopping? Not really my ideal plan for the day. What about going diving? Not a bad idea at all…
Pete and I had already planned to go diving, but the plan had been to go shore diving somewhere. Then Dennis extended an invitation to join him on the boat, a gracious invitation we quickly accepted. As a result, the morning of the 24th saw us leaving Honokohau Harbor looking for a dive site to try.
We did not go far from the harbor. First choice was a dive site called Sharkfin Rock just off Old Airport Park about two miles south of Honokohau. It is always a good sign when you can see the bottom 60 feet below through the blue water. Just inshore from the mooring a few surfers enjoyed the breaks along the park. Except for the one bodyboarder who was yelling at us to stop blocking his waves, as if a mere boat can have any significant effect on waves of any real size!
We found nothing truly unusual.. There were a number of nice encounters with reef regulars, some uncommon species of butterflyfish, a large day octopus, a young whitemouth moray. The second site at Eel cove was definitely one of the fishiest sites I have seen in quite a while. A lot of young fish to be seen. I expect the the more exposed site offers good feeding opportunities and less abuse from the aquarium collectors. I got a few good photos, particularly of the octopus. I have not seen what results Pete got from his efforts.
The day was simply a nice day to be out on the water, with good dive conditions that provided two nice dives. In the end I did do a little shopping. A stop at Costco was convenient as it is right above the harbor. There I grabbed a quick lunch and a couple things to keep our refrigerator stocked over the holiday.