Two of the brightest stars in the sky can be found in the constellation Centaurus. Visible in the southern sky after sunset throughout June, Centaurus is a half-man, half-horse appearing to leap over the Southern Cross. Alpha Centauri and Beta Centauri make up the front hoofs of the centaur. To locate these stars, find the Southern Cross low on the southern horizon, then look eastward for two nearby bright stars.

Although we see them as individual stars, Alpha Centauri and Beta Centauri are actually multiple star systems. Alpha Centauri, also called Rigil Kentaurus, consists of three stars bound together by gravity. The Beta Centauri system includes two stars, the brighter of which is known as Hadar.

Alpha Centauri is the closest star to our solar system. The light we see from Alpha Centauri was generated 4.39 light-years ago. When we look at any star, we are actually looking into the past.

Beta Centauri is much farther away at a distance of about 526.07 light-years. Although the stars appear to be at a fixed distance, in reality Beta Centauri is more than 100 times more distant that Alpha Centauri.

Astronomers measure the brightness of stars using a magnitude system. A star with a lower magnitude is brighter than a star with a higher magnitude. Alpha Centauri's apparent magnitude is -0.04. Beta Centauri is slightly dimmer with an apparent magnitude of 0.59. When you consider the stars' magnitudes in comparison with their relative distances, it becomes clear that Beta Centauri is putting out much more energy than Alpha Centauri.

Partial Lunar Eclipse

Very early on June 26, Hawaii observers will be treated to a partial eclipse of the moon. Partial lunar eclipses are not as dramatic as total lunar eclipses where the moon turns red, but they are still worth staying up late to observe. The partial eclipse starts on June 26 at 12:16 a.m. Through the next hour and a half, observers will see the full moon darken until only half of it is visible. Then Earth's shadow will slide off the moon gradually until the full moon is visible again by 3 a.m.

Unlike solar eclipses, you do not need any special filters to view the lunar eclipse. Anyone in Hawaii with clear skies should be able to see it.

Summer Solstice

On June 21 at 1:28 a.m., Earth reaches a point in its orbit around the sun known as a solstice. Since Hawaii is in the Northern Hemisphere, this is our summer solstice. People south of the equator celebrate this day as their winter solstice. As the longest day of the year, the summer solstice is celebrated by many cultures.