Category: Sky Events

Sky events

Perseid Meteor Shower

Over the next few days the Perseid meteor shower will peak. As the most reliable shower each year this is also the most viewed meteor shower. Plentiful shooting stars combined with warm summer evenings makes this shower the easiest and most comfortable to view across much of the northern hemisphere. Quite a difference from the other reliable showers such as the Leonids and Quadrantids, that occur in November and January. Consider a warm summer night under a dark sky full of stars, a picnic blanket, relaxing while shooting stars streak across the sky. What could be better?

Leonids in Orion
A pair of Leonid meteors streak through Orion
The Perseid meteor shower occurs when the Earth passes through a stream of debris along the orbit of Comet Swift-Tuttle. This shower has been consistent throughout recorded history, mentioned in Chinese, Japanese and Korean records as early as the 1st century. Active from July 17th to August 24th, the shower will build slowly for weeks before the peak. A week before or after peak the shower can still be seen with around 20 meteors each hour. The shower is a northern hemisphere event, for southern observers the radiant never rises above the horizon.

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Mercury Appears in the Evening Sky

The planet Mercury is starting an evening apparition. The planet should become visible this week just above the fading glow of the setting Sun as a magnitude -1 object. The planet is moving about 1° further from the Sun and higher in the sunset each day, reaching a maximum elongation of 27° on September 4th. This will be the best evening apparition for Mercury in 2015.

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Venus Disappears into the Sunset

The 2015 evening apparition of Venus is drawing to a close. Already quite low in the sky at sunset the planet will disappear into the bright glow over the next couple weeks. Venus will pass through inferior conjunction on August 15th and reappear in the dawn during the first weeks of September.

Accompanying Venus into solar conjuntion is the bright planet Jupiter, continuing their dance in the sunset.

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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 at perihelion on January 3rd, 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.

2014 Solstices and Equinoxes
  UT HST
Perihelion Jan 4 05:59UT Jan 3 19:59HST
Vernal Equinox Mar 20 16:57UT Mar 20 06:57HST
Summer Solstice Jun 21 10:52UT Jun 21 00:52HST
Apehelion Jul 6 02:59UT Jul 5 16:59HST
Autumnal Equinox Sep 23 02:30UT Sep 22 16:30HST
Winter Solstice Dec 21 23:03UT Dec 21 13:03HST
 
Source: NASA Sky Calendar

 

Conjunction

I missed the closest approach of Venus and Jupiter. Not for lack of trying. I had set up the telescope and camera in the driveway. A clear afternoon clouded over at sunset, leaving me only glimpses of the planets through a fleeting gap in the clouds. I had time to focus enough to see the crescent of Venus, which promptly faded from sight.

The next evening I am on the summit. No small telescope available, but I did have the camera to record a stunningly beautiful evening atop the mountain.

Conjunction
Venus and Jupiter over the Keck 1 dome

Venus and Jupiter Reminder

A reminder that this evening will see the close approach of Venus and Jupiter. Watching over the last week we have seen these two bright planets growing ever closer in the evening sky.

The closest approach will be about 0.3° tonight, June 30th at 16:14HST. They will be slightly further apart several hours later at sunset.

This is the best opportunity to see the pair at their closest for observer in Hawaiʻi. If you want to see the closest approach you can also try to observe the conjunction in the late afternoon sky. Both planets are bright enough to see in the daytime.

After this the pair will separate slowly and disappear into the sunset glow together.

At their closest the two will be easily close enough to bee seen together in the low power view of amateur telescopes. It makes a fascinating sight to see the two planets together in the eyepiece.