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  • Rapt in Awe

    My Journey through the Astronomical Year

    Think of this as a "companion text" to this, the main web site. Not required reading, butI hope you'll find it interesting and helpful.

June 2012 Events – Venus at the start, Venus at the end – and lots of cool stuff in between

Here’s a quick summary of June 2012 highlights:

All month – Mars and Saturn

Mars and Saturn put on a continuing display in the southwest – they are near equal in brightness and very close – in brightness – to the first magnitude guide stars, Regulus and Spica.

Mars, Saturn, Regulus, and Spica are the bright “stars” we see in the southwestern sky on a June evening. Can you put them in order of brightness? (Answer at the end of this post.) Click image for larger view. Prepared from Starry Nights Pro screen shot.

June 4 – Partial eclipse of the Moon

This event favors the western United States and Australia – but some parts of the eastern US can see some of it. First contact for the penumbra- the faint part of Earth’s shadow – is at  08:48:09 UT; the umbra makes contact at 09:59:53 UT, and the umbral phase is over at 09:59:53 UT. The penumbral phase ends at 13:18:17 UT.

For a map showing visibility of this event throughout the world, as well as other details, please go here.  To convert Universal Time (GMT) to your local time, please go here. GMT is selected as the default and eclipse times are in 24-hour format.

June 5-6 – Transit of  Venus

Historic  Transit of Venus – you don’t want to miss this one. Of course, you need the weather to be on your side, plus proper safety precautions for viewing the Sun. Go here for all the details.

June 20 – The Summer Solstice

The sun rises and sets as far north as it can; twilight seems to last forever; and the really dark night is darned short. Here in Westport, MA, the Sun sets at 8:22 pm EDT, but astronomical twilight doesn’t end until 10:34 pm EDT. That’s when it’s truly dark. And the morning phase of astronomical twilight begins at 02:59 am EDT. That gives us just four hours, 25 minutes of full darkness that night.

June 15 to early July – Catch the elusive planet Mercury in the evening sky – special treat June 21!

For many years I thought Mercury was really difficult to see. It isn’t, but it has that reputation for a reason. The problem with seeing Mercury is you have to know exactly when and where to look, but every year there are two or three good opportunities. This year one of them comes in the last couple of weeks of June.  During that period Mercury will be roughly 10 degrees above the horizon (one fist held at arm’s length –  to the north of west. The planet will be playing tag with the familiar Castor and Pollux – the Heavenly Twins – and will make a fine group with them and the crescent Moon on June 21.

Here are three  charts that should help you find it – but pay attention to the time. That is critical. You have to catch Mercury after sunset when the sky is dark enough for it to be seen, yet not too long after sunset or the planet will be too close to the western horizon and difficult to see through all the atmosphere. I suggest you start searching with binoculars about 15 minutes after sunset. Mercury should be visible to the naked eye around 30 minutes to an hour after sunset depending on local conditions. It’s easier to see with the naked eye once you spot it in binoculars, and it will be a bit brighter than the Twins.

All the named stars will be roughly the same brightness as Mercury, but it is hard to make comparisons in a twilight sky because the nearer to the horizon a star (or planet), the lighter the background against which you’ll see it. Click image to see a larger version. Prepared from Starry Nights Pro screen shot.

Click image to see a larger version. Prepared from Starry Nights Pro screen shot.

Click image to see a larger version. Prepared from Starry Nights Pro screen shot.

Last week of June – Jupiter and Venus vie for the title “Morning Star”

The giant planet Jupiter is back with its four bright moons and will be with us for many months to come.  It starts out the month rising just before the Sun, but by the end of the month will rise a full two hours before dawn. What’s more, it will be joined by a crescent Venus, fresh from its historic transit of the Sun at the start of the month.  And if that’s not enough, this all takes place in one of the most beautiful sections of the night sky with the charming cluster of the Pleiades hanging above the scene and the  Hyades just coming into view below it.

To see this you need an unobstructed eastern horizon; binoculars will make it much more enjoyable, and I plan to start looking about two hours before sunrise when the Pleiades are visible in a dark sky. Jupiter and Venus may not pop into view for another hour, and by then morning twilight will be getting strong – but they are so brilliant it shouldn’t matter.  However,  if you don’t see them on June 29, by all means give it a try any of several days before or after that date. From morning to morning Venus will appear to be trying to overtake Jupiter – and will get a bit closer in early July.

Capella, one of the brightest stars is near magnitude 0 – Jupiter about -2 and Venus a dazzling -4.4. Use binoculars to see the Pleiades. Click image for larger version. Prepared from Starry Nights Pro screen shot.

Answers to the brightness question

On June 15 Saturn shines at magnitude .61 and thus is the brightest, but Mars is extremely close at magnitude .7. (Extra pat on the back if you got these two correct! ) Spica is next at .98 and then Regulus at at 1.34. As the month goes on both Mars and Saturn will get a tad dimmer, but the order of brightness will remain the same – Saturn, Mars, Spica, and Regulus.

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