Category: Astronomy

Exploring the cosmos

Apehelion

Today the Earth is furthest from the Sun, a point called apehelion. We will be about 152,096,000km (94,508,000miles) from the Sun. Compare this to the 147,099,000km (91,403,000miles) we were be at perihelion on January 1st, a difference of about 4,996,000km (3,104,000miles) occurring throughout one orbit.

It may seem odd that we are actually at the furthest for the middle of northern summer, 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

 

The Moon, Mars and Jupiter

Tomorow morning, July 6th, will see a nice 5-7° triangle made up of a slim crescent Moon, Mars and Jupiter. Look for the trio to start rising about 04:30 HST with Mars rising first, followed by a 2.5% illuminated Moon. Last up will be Jupiter, rising about 04:55 HST. The Sun will not rise until 05:48 giving plenty of time to enjoy this conjunction.

Jupiter Appears in the Dawn

This week will see the reappearance of Jupiter in the dawn sky. This morning the planet will be 10° above the rising Sun, climbing quickly higher each morning. Look for a bright, -2 magnitude object directly above the bright glow of dawn.

Over the next couple weeks there will be a nice series of conjunctions between Jupiter, Mars, Mercury and the Moon.

The Lights Went Out in Kapaʻau

An interesting bit of news passed along, HELCO was planning a power outage at 8pm. I expect my reaction to this information was a little different than most… This is great! With a school star party scheduled at Kohala Elementary, the news that the entire town would be dark for the star party was a pleasant surprise.

Mr. O's Stars
Mr. O shows a family the stars at Kohala Elementary
It would be a long day… Up early to pack the telescope, up to the summit for a day of working on the AO system, troubleshooting a couple issues plaguing observations. Then an early departure from the summit to head for Waimea and over the Kohala Mountain Road to Kapaʻau on the very north end of the island.

I stopped to get dinner in Hawi on the way. Surprisingly the Bamboo Restaurant was open early, they normally do not open until 6pm. I find out that the whole town was bracing for the power cut at 8pm, with events and opening times moved up. Not everyone had gotten the notice, I was the only diner in the restaurant. A pleasant meal chatting with the staff and a good burger were just what I needed, food and a brief rest to prepare for the evening.

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Scientists Discover System with Three Planets in Habitable Zone

W. M. Keck Observatory press release…

A team of scientists recently confirmed six, and possibly seven, planets orbiting a star system a mere 22 light-years from Earth. More importantly, three of those planets are super-Earths, lying in the Goldilocks Zone where liquid water could exist, making them possible candidates for the presence of life. This is the first system found with a fully-packed habitable zone. The findings will be published in the journal Astronomy & Astrophysics on June 26.

Previous studies of the triple star system called Gliese 667C showed the star hosts three planets with one of them in the habitable zone. Now, a team of astronomers has reexamined the system by re-mining existing European Southern Observatory’s HARPS data and combining it with data collected from the W. M. Keck Observatory and the Magellan Telescope to find evidence for up to seven planets around the star. These planets orbit the third faintest star of a triple star system. The two other suns would look like a pair of very bright stars visible in the daytime and at night they would provide as much illumination as the full Moon.
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