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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.

Start your year with Mercury!

Start looking for Mercury in your southwestern sky  half an hour after nightfall. Use the crescent Moon as your guide. Move from it to brilliant Venus. Mercury and Hupiter will be much dimmer - about as bright as the two "signpost" stars, Fomalhaut and Altair. An arrow drawn from the Moon to Jupiter points roughly to the Sun and illustrates the approximate location of the plane of our solar system - the area of the sky where you'll always find the planets, (Adapted from a Starry Nights screen.)

Start looking for Mercury in your southwestern sky half an hour after nightfall. Use the crescent Moon as your guide. Move from it to brilliant Venus. Mercury and Jupiter will be much dimmer - about as bright as the two "signpost" stars, Fomalhaut and Altair. An arrow drawn from the Moon to Jupiter points roughly to the Sun and illustrates the approximate location of the plane of our solar system - the area of the sky where you'll always find the planets, (Adapted from a Starry Night screen.)

Update: What I actually saw January 1, 2009 – First, I was surprised how much Mercury had moved in just two days – it is fast! Having Jupiter nearby made it easy to see the changes from night-to-night. Second, it’s still a difficult object for my old eyes without binoculars.  However, it was very easy in binoculars – much easier than my attempt t at pictures may indicate – though the pictures do give you a sense of what to expect as Mercury climbs higher each night for the next several nights.  Here’s a wide view, typical of what you see with th naked ye. The moon and Venus are obvious – Mercury and Jupiter certainly aren’t.

That's the crescent moon up to the left, then Venus. The arrow points to the area near the tree where Mercury and Jupiter could be seen easily with ordinary binoculars.

That's the crescent moon up to the left, then Venus. The arrow points to the area near the tree where Mercury and Jupiter could be seen easily with ordinary binoculars.

And here’s a view where I used a 300mm lens to zoom in on that area near the tree line.

Mercury is the higher, fainter of the two planets. This picture was taken just seconds after the one above, but zoomed in on the tree line.

Mercury is the higher, fainter of the two planets just visible in the notch in the trees to the left. This picture was taken just seconds after the one above, but zoomed in on the tree line.

Update: December 30, 2008 – Just checked and with 12X36 IS binoculars I found Mercury about 20 minutes after nightfall. It was seen easily against a yellow sky with Jupiter – much brighter and easier to spot – above it, but both fitting easily in the same binocular field. I could not see it with the naked eye,however, although sharper eyes than mind might have. At this time it was only about 7 degrees above the horizon – less than a fist. Ten minutes later I could see it with the naked eye, but it was already inthe tree branches!

Original post:

Of the five bright planets known since antiquity, Mercury is the most elusive.  I had been an amateur astronomer for at least 10 years before I tracked it down one morning. It’s funny. When you do see it, you say “what’s the problem. That was easy.” But without knowing exactly when and where to look it can be difficult – and it is always near the Sun and thus near our horizon.

Everything appears dimmer near the horizon because you’re looking through more of our atmosphere than when looking straight up. In addition, there are frequently low clouds and haze on the horizon that may not be apparent – except that you can’t see what you expected to see!

The final issue is a little game of hide and seek. With each passing minute the horizon creep up threatening to swallow Mercury. But with each passing minute the sky gets darker making it a little easier to see a bright planet. Objects higher in the sky, such as Altair and Fomalhaut, may be visible when Mercury isn’t simply because the sky behind them is darker.

Jupiter, significantly brighter than Mercury but not nearly as bright as Venus, should be a handy guide on January 1. As the month wears on Mercury put more distance between itself and the Sun and thus will appear to climb a bit higher in our sky, being near its peak on January 7, 8, and 9th. By that time, however, Jupiter will have sunk lower and may be quite difficult to see. The two planets are  closest to one another this month on January 1.

Such a pack of variables are typical of observing and make it always interesting. You can see Mercury with your naked eye, but it will be easier to find it first in binoculars. Both it and Jupiter should appear in the same binocular field of view on January 1.  By the 7th, 8th and 9th the two may just barely fit in the same field of view, but don’t count on it. Depends on your binoculars. By the middle of the month Mercury will be too low to see easily.

So when should you look? I want to go out on the first. But if it’s not clear, I’ll try any night in these first couple of weeks. Mercury pops into the morning sky by the end of the month – it sure does get around! But not every appearance of Mercury is equal – sometimes it appears much higher above our horizon in a dark sky than at other times. On this appearance it will peak at nearly 10 degrees above the horizon, 30 minutes after nightfall. That’s good. Remember – 10 degrees is about the area covered by your fist when held at arm’s length.

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2 Responses

  1. Happy and Healthy New Year to you and Bren and family.
    Thanks for the tips on finding Mercury.

  2. Happy New year to you and Brennda and your fam
    I Went out Dec 30th with my 22×100 binos and saw Mercury above Jupiter. I was in doubt but you comfimrd what i saw.

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