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    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.

Events – June 2013 – Venus chases Mercury, Saturn is due south, and the Summer Solstice arrives

This is a delightful time to find the ever elusive Mercury because through the first two weeks of June it puts on its best show of the year for those in the Northern Hemisphere and it’s relatively easy to find because brilliant Venus points the way.

Look west about 30 minutes after Sunset on June 1, 2013 and you can find three planets ina row. Venus should be obvious to the naked eye. Find it and put it int he bottom of your low-power binocular field and you should see Mercury near the top of the field of view. Move Venus to the top and you should pick up Jupiter near the bottom of the field of view. Jupiter is brighter than Mercury, but may not appear to be because it will belower and more impacted by looking through the atmosphere and the twilight which will be brightest near the horizon.

Look west about 30 minutes after sunset on June 1, 2013 and you can find three planets in a row. Venus should be obvious to the naked eye. Find it and put it in the bottom of your low-power binocular field and you should see Mercury near the top of the field of view. Move Venus to the top and you should pick up Jupiter near the bottom of the field of view. Jupiter is brighter than Mercury, but may not appear to be because it will be lower and more impacted by looking through the atmosphere and the twilight which will be brightest near the horizon. Jupiter will soon drop out of sight but for the next two weeks Venus and Mercury will make easy targets.

Special June 2013 dates for viewing Mercury, Venus, Jupiter and the Moon:

  • 1 – Mercury at its brightest and Jupiter still in view.
  • 9 – A very thin crescent Moon little more than one day old will be roughly 10 degrees – one fist – beneath the pair of planets – Venus and Mercury.
  • 10 – A much easier to see – and quite pleasing – will be a 2-day lunar crescent  beside the pair (just south)  and almost fitting in the same binocular field of view.
  • 11 – The 3-day crescent Moon will have climbed well past the pair, but still make a nice show.
  • 18 – Mercury has reached its peak and started back down and on this date drawing within a couple degrees of Venus – just south. The two will be quite high – about 11 degrees half an hour after sunset, but Mercury will have faded to magnitude 1.1 making it a challenge to pick out in the twilight.

Also this month:

But let’s start with Mercury because the speedy little planet is always a challenge to see. Why? First, because it is very fast. Earth chugs along at a “mere”  66,000 miles an hour in its annual journey around our star, the  Sun. (Doesn’t feel like we’re going that fast, does it?) But Mercury, being closer to the Sun, moves much faster –  it covers a much smaller orbit at a blazing 107,000 miles an hour. So that means when it is well placed for observing it doesn’t stay that way long and it’s easy for the weather and the rest of life to get in the way of seeing it.

What’s more, because it is so near the Sun we only see it as it pulls out to one side or the other  of the Sun and it does that for relatively brief intervals.

And even these quick glimpses vary considerably because it’s orbit is much more lopsided than most. At one point it can be as much as 43.6 million miles from the Sun – and at another it may be as little as 28.6 million miles. (In comparison, Earth can vary from roughly 94.5 million miles from the Sun to 91.4 million miles.)

How far it is from the Sun impacts how easy it is for us to see. If close to the Sun it either rises or sets in strong twilight – and since it seldom gets much brighter than magnitude -1, it can be  quite difficult to pick out in the twilight. And even when it gets pretty far away from the Sun, it’s so small that it never becomes as bright as Venus – in fact, in June it will be easily outshone by Jupiter and Venus.  This June, Mercury will reach a maximum brightness of -0.4 and that on the first day – it grows a bit dimmer each night thereafter, though this will be hard to judge because it also puts more distance between it and the Sun, so that means we see it against a darker background each night.

Cool, huh? I mean it moves a little bit more into darker sky each night – but at the same time it dims a little each night – doesn’t want to make things too easy for us!  😉

But sometimes several factors combine to give us an especially good look at Mercury and this June is such a case – with the added bonus that the much brighter Venus will be near it and thus point the way to finding Mercury.  The basic routine is simple. You want to start looking about 30 minutes after sunset and when you spot Venus, turn your binoculars on it – about any binoculars will do – and for much of the month Mercury will fit  in the same field of view looking like a significantly dimmer star.  As it gets darker you should be able to pick it out with your naked eye – though if you wait too long it will be too close to  the Western horizon – so timing really counts.

As the month progresses Mercury will be a bit higher each night 30 minutes after sunset and Venus will appear to chase it – but Jupiter will drop out of view in just a few days.

Your first challenge, of course,is to merely find the planets in your evening sky and that require an unobstructed western horizon, good clear skies, and appropriate timing – and binoculars sure help, but aren’t absolutely necessary.

But what are you really seeing?

Or maybe the better question is: Why do you see the planets this way?

For the answer we turn to an Orrery – and there’s one online that can be found here. I used it – and modified the view with labels and arrows – to produce the two images that follow.  Essentially this is a view from overhead showing the counter-clockwise motion of the planets around the Sun.  It is only very roughly proportional and your challenge is to look at the Orrery view, then mentally place yourself on the Earth and imagine what your view at sunset would look like. Remember – now you’re getting down in the plane of the solar system and looking outward and what you see is a two-dimensional view that  cancels out the huge distances between the planets.

This June 1 view holds true for Mercury and Venus formost of the month. Jupiter quickly gets too close to the Sun. What we see at sunset are theplanets to the left of the arrow pointing west. As the Earth rotates, the arrow sweeps to the left and theplanets vanish from our view - although Saturn, seen int he southeast at the start of the evening, appears to climn higher in our sky as we turn towards it.  But, of course, nothing stands still. The Planets also revolve around the Sun, so from night to night Venus and Mercury will close the distance between themselves and Earth. The result in 30 days is shown in the next image.

This June 1 view holds true for Mercury and Venus for much of the month. Jupiter quickly gets too close to the Sun. What we see at sunset are the planets to the left of the arrow pointing west from the Earth. As the Earth rotates, the arrow sweeps to the left and the planets set – although Saturn, seen in the southeast at the start of the evening, appears to climb higher in our sky as we turn towards it. But, of course, nothing stands still. The planets also revolve around the Sun, so from night to night Venus and Mercury will close the distance between themselves and Earth. The result in 30 days is shown in the next image.

By the end of the month our view tot he west at Sunset shows us only Venus. Jupiter has long vanished fromt he scene and infact, may just becoming visible inthe pre-dawn sky with Mars.  Venus remain in view,  and Staurn is the dominant planet for much of the Summer night in 2013.

By the end of the month our view to the west at Sunset shows us only Venus. Jupiter has long vanished from the scene and in fact, may just be coming visible in the pre-dawn sky with Mars. Venus remains in view, and Saturn is the dominant planet for much of the Summer night in 2013.

As I watch this wonderful dance of the planets from night to night – and the changes are especially obvious with the swiftly moving inner planets of Mercury and Venus –  I try to get a picture in my minds eye of what’s really happening. Do this enough and when you look at a planet or the Moon in the sky, you can easily sense exactly where they are  in their orbits around the Sun – and where you are in respect to them. I find this a very satisfying piece of mental gymnastics – that we little creatures on our tiny little spaceship Earth, whirling and hurtling about the Sun at incredible speeds, have been able to figure this out. Don’t get me wrong – I take no c edit for that – just one of those special moments when I feel proud to be one of the billions of homo sapiens  here and feel maybe we have earned that name – sapiens indeed! 😉

One last piece of dynamics at work. As mentioned, Mercury is at its brightest at the start of the month.  By the 14 it has dropped about one whole magnitude to 0.76, by the 21st it’s magnitude 1.5, and by the 28th magnitude 2.6. So it will be getting harder and harder to see as it drops more and more into the twilight zone and as it loses brightness. Why does it get dimmer? Look at the Orrery charts – it is moving to a position between us and the Sun and just like the Moon, as it gets between us and the Sun it goes through phases. By the 28th it is a thin crescent and so is reflecting very little light our direction. (These phases can be seen with a small telescope, but you will not detect them with binoculars.)

Mercury and Venus week by week

The following chart shows you the changing positions of Venus and Mercury during June 2013. All are for 30 minutes after sunset for mid-northern latitudes, and all are prepared from Starry Nights Pro screen shots with labels added. Venus never gets much higher than 10 degrees above the horizon – not only throughout June, but essentially for the rest of the year it will be a pretty constant western star – slipping southward somewhat and eventually, in late fall, rising some , before going off stage in January 2014. Mercury’s appearance int he West is strictly for June and as you can see, by the end of the month it’s heading quickly for the horizon and is quite faint.





Saturn – a southern star!

Wait until about an hour after sunset during June 2013, then look due south.  Almost four fists above the horizon (from mid-northern latitudes)  and about one fist apart are two bright “stars.” The slightly brighter one on the left (east) is Saturn. The other – which should appear bluer – is the first magnitude guidepost star  Spica. Down to the  lower left is another star of about the same brightness, Antares. Compare these three – they are roughly the same brightness, but Antares is tinted red, Saturn yellow, and Spica blue.  They  make a good introduction to noting star colors – which to my eye are more tints, but certainly detectable.


Who can resist the Solstice magic?

We’re fascinated with extremes and since the Sun is responsible for maintaining all life on Earth it’s rather natural to want to track its movements in our sky and mark its extremes. There’s no better time to do so than when it reaches it’s most northern point – the Summer solstice. And if you want to be really accurate that happens at 1:04 am EDT on the morning of June 21. So the time to greet the astronomical start of Summer is to mark the sunrise on June 21.

That said, this is more for those who are fond of records. Truth is you will be hard pressed to tell the difference of where exactly where the sun rises or sets a couple days before that date, or a couple days afterwards. The changes are just too small for us.  So you have to take the word of those who track such things with sophisticated math and instruments – 1:04 am June 21 is the time and date when the Sun reaches its most northerly point.  And the shortest night of the year is June 20-21.

All of this, of course, is for northern hemisphere observers. Our friends Down Under are marking the start of winter.

And speaking of special events . . .

On the night of June 22-23 we have a full Moon – the largest full Moon of the year.

Why is this larger than other full Moons? Because it is closer to us at this particular full Moon. How much larger is it? Significantly – but not so much that you really can tell the difference. To do that you need to see a larger full moon next to a small full Moon – and you can do that by going to this web site which gives a wonderfully detailed explanation.

Meanwhile, just sit back and enjoy it – and don’t confuse this with the Moon illusion phenomena – that is simply our eyes and brain playing tricks on us to make the Moon (or the Sun) look much larger when it is near the horizon, than when it is high in the sky.


June 2010 events: A month of surprises involving Jupiter, a comet, and maybe even some meteors!

Note: While many of the following events are visible throughout the world, the exact time and location in the sky can be dependent upon your latitude and longitude. Since I’m in the mid-northern latitudes (41.5N, 71.1W), specifics, where place-and-time-dependent, are calculated for this location.

Observing Jupiter and Uranus

June promises to be full of surprises, most revolving around getting up early to enjoy a summer dawn! I’m circling the weekend of June 12-13 on my calendar as special in terms of getting up early, and I’m hoping for a triple header: viewing Jupiter, finding Uranus, and seeing Comet McNaught. For the meteors, it will be June 23 and in the evening – though there’s a real big question mark around this event. Let’s start with a sure thing – Jupiter and Uranus.

You can’t miss Jupiter. It’s the brightest “star” in the southeast in our morning sky. You can easily miss Uranus. It’s barely naked eye visibility in the best – least light-polluted – locations and hard to pick out from true stars in the area. But on a morning in June finding Uranus should be an easy task with any decent pair of binoculars because Jupiter will guide you right to it.

It’s Jupiter that offers our first surprise for those who can turn a small telescope on it. Usually even the most modest telescope will show you two dark belts on Jupiter – but this June there’s no telling Jupiter missing bandexactly what you’ll see. Jupiter’s been hiding behind the Sun recently, but when it emerged in May it surprised planetary observers by displaying just one of its major trademark dark bands. The other had vanished!

If you have a small telescope and point it towards Jupiter on a June morning will you see it this way? Can’t say. That’s why it will be a surprise. Veteran observers think the second band could come back quite quickly – in just a week’s time, for example. They say this sort of thing is rare but has happened before. One theory is that high, thin, light-colored clouds are covering the band, and these clouds may vanish without warning – just as they appeared without warning.

Jupiter is second only to Saturn in its appeal to small telescope users, not only because of its bands, but because of the constant dance of its four Galilean Moons, which you can detect if you can manage to hold even modest binoculars, such as 10X50s, steady. And Jupiter this year will be doing an even grander dance with its outer cousin, Uranus. The two gas giants come quite close to one another – as viewed from Earth – three times in the next seven months, the first being in June. That means Uranus, usually a difficult object to find because it is so faint, will be an easy target for binocular and small telescope users – though its disc is so small it will hardly show except in a telescope at high power.

Here are a couple of images giving you the position of the two planets early in the month and near the end of the month.


Click image for a larger view. Image developed from "Starry Nights Pro" screen shot.

For a printer-friendly version of the appropriate chart for on or near June 6, 2010, click here.

For a printer-friendly version of the appropriate chart for on or near June 30, 2010, click here.

A good project would be to take the print out of the first chart (June 6) and mark the position of each planet when observed about once a week. You’ll notice that both drift to the east (left) against the background of stars, but Jupiter’s progress appears much faster because it is so much closer to us. That would help you appreciate the fact that when Uranus was discovered March 13, 1781, by the English astronomer William Herschel, it effectively doubled the size of our solar system! (And if you don’t want to get up early several mornings to actually see this, just study the charts above, but be sure to click on them to see the larger version. 😉 For more on Uranus see the May events entry.

The two planets come closest on June 8 when they are less than half a degree apart. However, any time during the month they will easily fit in the same binocular field of view. I’m aiming for observing on or near the 12th simply because it’s a weekend, and since there’s no Moon in the sky to drown things out with its glare, that will also be a good time to spot the comet.

Seeing Comet McNaught at its best

Comets are notoriously unpredictable and catching them at their best is a game you play, trying to balance the time when the comet is close to the Sun – and thus usually brightest – against the approach of dawn, which lightens the sky behind the comet as it gets closer to the Sun and thus makes it more difficult to see.

Northern hemisphere observers are overdue for a nice comet and McNaught (C/2009 R1) could be it. Astronomy magazine thinks it may reach naked-eye brightness with a distinct tail. Sky and Telescope seems a bit more cautious in its prediction, but still thinks it will be very nice in mid-June. In 2007 another Comet McNaught (C/2006 P1) put on an absolutely spectacular display for southern hemisphere observers, becoming the brightest comet in 40 years seen from anywhere on Earth. Sadly, for those in mid-northern latitudes the show was nowhere near as good and was so brief many missed it. I was lucky to catch it, but against strong twilight, so it didn’t show at its best. I took this shot of Comet McNaught over Horseneck Beach in Westport on January 11, 2007.


Bren and I saw an earlier Comet McNaught in strong twilight and amidst clouds in 2007 shortly after sunset.

A recent study, however, has found that Comet McNaught was not only a spectacular sight from the southern hemisphere, but also probably the largest comet on record.

It’s fairly safe to say this Comet McNaught will not be nearly as spectacular – but it could be quite nice, especially in binoculars, and it should be easy to find as it will be going past some well-known stars. In fact on the morning of the 12th it will be right between Algol (the Demon Star) and Mirfak, brightest star in the constellation Perseus. Here’s a chart – but take the show of the comet’s tail as simply a rough indicator of the tail’s direction. I doubt it will be this large. (Starry Nights software, from which this chart was derived, shows all comet tails about the same length.)

Comet McNaught 2010

Click image for larger version. Chart derived from "Starry Nights Pro" software.

For a printer-friendly version of this chart, click here

As with the Jupiter/Uranus event, Comet McNaught should be visible much of the month. But early in the month it will be dimmer, and later in the month it will be so close to the Sun that the dawn twilight will drown it out. The middle of the month seems like the best bet for catching the comet when it’s quite bright and will be high enough in the sky to see well during a time period when the sky behind it is fully dark.

The beginning of astronomical twilight is when the sky starts to brighten and continues to do so right up through sunrise. For my area – and other mid-northern latitudes – astronomical twilight starts about 3 am in mid-June, more than two hours before sunrise. (Tables for astronomical twilight times for your area can be easily created at the U.S. Naval Observatory site here.) My plan, weather permitting, is to go out on Saturday morning, June 12, to a local observing sight that has a beautifully clear and dark eastern horizon, and to be there by 2:30 am EDT. That will give me an opportunity to see Comet McNaught when it is about 15 degrees above the northeastern horizon. I expect to have a good view right up through 3:30 am – after that I expect the interference from the approaching dawn to become serious. (That’s the date of new Moon, so it will offer no interference for several days either side of this date.)

But again, comets just aren’t that predictable. Back in 1973 I published a cover story in Popular Science quoting experts who predicted that Comet Kohoutek would be the “comet of the century.” It was no such thing and I was embarrassed! And the most exciting comet of recent years for me was Comet Holmes in 2007, which suddenly – and inexplicably – broke into naked eye glory when no one was expecting it to do any such thing.

What can be done with accuracy is to predict when and where you can expect to see Comet McNaught. Those predictions you can trust. And you should begin your search with the naked eye, but I suspect binoculars will give you your first view, and it may take a small telescope to give you a really decent look at it.


  • For an orbit diagram of the current Comet McNaught see this page.
  • This Comet McNaught is the 56th comet discovered by this man. Why so many? Well, for the past five years or so it’s been his job to find comets  that may pose a threat to Earth and he has the tools to do it. Go here to learn more.

Catching the elusive Bootid meteors

If anything in amateur astronomy seems riskier than making predictions about comets, it’s making predictions about meteor showers – especially unusual ones that flare up on rare occasions. But Astronomy magazine is carrying a prediction that on the night of June 26 – and we’re talking the more comfortable evening hours now – we could get quite a display.

It reports that the International Meteor Association predicts that the peak of this shower could occur on June 23/24 between 7 pm and midnight EDT. Well, of course that means this favors the East Coast and even then, it may peak while it is still light, since you won’t have complete darkness until after 10 pm.

Frankly, I’m very skeptical about this one, but if it’s clear that night I’ll do some observing of double stars and keep an eye out for meteors at the same time. The problem is simple: at 10 pm the Moon, just a couple of days short of full, will be low in the southern sky, but still high enough so I think it will drown out many of the meteors. So what we have here is a prediction that a normally quiet “shower” may suddenly have a real outburst worth seeing – but that outburst could come during daylight or twilight, and if it comes during full darkness it will be competing with bright moonlight. That just doesn’t seem all that promising. But then, what can you lose being out on a warm June evening with clear skies, bright moon, and and fireflies? And now you know you may get lucky and see some bright meteors as well – maybe a whole lot of meteors 😉

June’s Calendar – a chronology and review

You have the highlights above – here’s a summary of them, along with some additional June events, in chronological order.

  • June 4 – Last quarter Moon
  • June 5,6,7,8 – Watch Mars pass close to Regulus – note color difference! (Mars is just a tad brighter.)
  • June 6 – Good time to start your search for Uranus and Comet McNaught
  • June 12 – New Moon – prime weekend for an early morning expedition to see Jupiter, Uranus, and Comet McNaught
  • June 14 – Brilliant Venus just above a thin crescent Moon – nice!
  • June 19, 20 – Venus is just 1 degree from the Beehive – use binoculars to see the stars near this most brilliant planet.
  • June 21 – The Summer Solstice – and shortest night of the year. Comet McNaught should be getting quite difficult to see by now.
  • June 23 – Cross your fingers and hope for some spectacular meteors appearing to radiate from Bootes still high in the evening sky.
  • June 26 – Full Moon – and a partial lunar eclipse in the morning sky for folks in western North America and points west.
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