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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.

Look East: March 2013 Roars in like a sickle and triangle! (Huh?)

Sure, I’d like to tell you March roars in like a lion – but honestly it’s easier to point to the sickle and the triangle and the “Little King” we call Regulus, this last being the new guidepost star for March. But there is a lion there, too. Let’s look at the sickle and triangle first, though, because they’re two very easy asterisms you’ll see in the east about an hour or so after sunset. The Big Dipper off to the northeast gives you an idea of size for comparison.

This is the eastern sky as it will appear about an hour after sunset from mid-northern latitudes. The circle represents a typical field of view for low power binoculars. While you should see the brightest stars easily, in twilight - or in typical light pollution - you'll find that binoculars will show some of the fainter stars nearby and help you be sure you have identified the correct bright star.  The Mars position is for the 15th, but it will change a little each night.  Click image for larger view. Prepared from Starry Nights Pro screen shot.

This is the eastern sky as it will appear about an hour after sunset from mid-northern latitudes. Click image for larger view. Prepared from Starry Nights Pro screen shot.

Click for printer friendly version of the above chart.

OK – so can you make this into a lion? I find it fairly easy if I consider the sickle his head and mane – and I consider the triangle his rear haunches. I leave the rest to my imagination and don’t really attempt to connect the dots.

Leo does look much like the Lion depicted inthe 1603 Bayer catalog.  Click image for larger version.

The stars of Leo do indeed trace out some key parts of the Lion depicted in this plate from the 1603 Bayer atlas. (Click image for larger view.) Note that the bright star that marks the tail is named “Denobola,” which in Arabic really does mean “tail.” We encounter this also in the tail of Cygnus the Swan where the bright star is named “Deneb.” The Arabic star names are frequently descriptive. (Image courtesy of Linda Hall library of Science, Engineering and Technology.)

Regulus, our new bright guidepost star for this month, means “little king,” or “prince,” in Latin. That fits right in with the lion‘s reputation as King of the Beasts. And what a lovely image to have a prince leading a lion onto the night-time stage this month!

Is Regulus memorable in its own right? Well yes. It’s a star that is spinning so fast that if we could see its disc, it would look like a beach ball that someone sat on. It takes Regulus about 16 hours to make one rotation – in comparison, our Sun, a smaller star, takes about a month to rotate. In fact, if Regulus were spinning just a bit faster, it would spin itself apart!

The rapid spinning gives Regulus an equatorial diameter that is about one-third bigger than its polar diameter. This also results in the polar regions of Regulus being much hotter than its equator.

Regulus is also a multiple star system, but as such rather dull visually. The second star in the system is much fainter, so it can barely be detected by a skilled observer using binoculars – and in a telescope it’s so far away from the primary star that the two stars don’t seem like a pair at all. Both these stars are spectroscopic doubles – meaning the companions are so close we can’t see them with a telescope.

Though a relatively young star – about 250 million years as compared to the five-billion-year age of our Sun – Regulus is apparently nearing the end of its normal life as a “main sequence” star. That is, it’s about to finish burning hydrogen, which means it will soon go into the last stages of its life. But according to Jim Kaler, Regulus is also a curious case. It appears to have a very close white dwarf companion which scientists believe once was much larger and brighter than Regulus. But the gases were drawn from the white dwarf into Regulus, making Regulus both huge and bright and causing it to spin the way it does.

In total, Regulus is another example of how what looks like a common star to us, is quite fascinating when seen in the light of modern science.

Vital stats for Regulus:

• Brilliance: Magnitude 1.35, 22nd among the brightest stars in our sky; shines with the luminosity of about 150 Suns.
• Distance: 77 light years
• Spectral Type: B7V
• Position: 10h:08m:22s, +11°:58′:02

The buzz about the Beehive (M44) and Leo’s whiskers – a binocular treat!

In ancient times the constellation Leo extended much farther east and west, and M44 was considered to be its whiskers.

from “The Next Step – Finding and Viewing Messier Object” by Ken Graun

Whiskers indeed! I like that. It’s a great way to remember where to look for M44, for if you can find the Sickle – the huge head and mane of Leo – then all you have to think is “now where would his whiskers be?” Scan 2-3 binocular fields in that direction – westward – and you should soon stumble upon M44, the Beehive. Here is a chart you can use to find it. Do wait  until about two hours after sunset when it is really dark and M44 is well up in the sky.

Click image for larger view. Prepared from Starry Nights Pro screen shot.

Click here to download a black-on-white (printer-friendly) version of this chart.

M44 also is known as “the Beehive,” and Praesepe, which is Latin for manger. And if you have dark skies, away from light pollution, you will see this as a small, wispy cloud, perhaps suggestive of Leo’s whiskers. It is, in fact, a beautiful star cluster as binoculars or a small telescope will reveal. Galileo first discovered its true nature, and in this hazy patch counted more than 40 stars. You should see about that many with your binoculars. This is one of the nearest star clusters to us, and although there is still debate over its exact distance, it is around 580 light years. That compares with about 400 light years for the Pleiades. The two clusters are pretty close to the same size, but M44 is considered much older. M45 – the Pleiades – is estimated to be 78 million years old, while M44 is thought to be about 660 million years old. As star ages go, they’re both quite young. But open clusters, such as these, do not last too long – the members stars tend to get drawn off by close encounters with other stars as the whole clusters moves about our Milky Way galaxy.

The Latin name, Praesepe, is worth examining because it explains the names of two relatively bright stars which flank it – Asellus Borealis and Asellus Australis. Borealis means “northern” and Australis means “southern.” Asellus means “ass” – as in donkey – and Praesepe means “crib” or “manger.” In other words, the Beehive apparently looked to some like a pile of hay in a manger, and these two flanking stars were donkeys eating that hay, one to the north and one to the south. In binoculars the scene should look something like this.

M44 and surroundings as it would appear in binoculars with a 5-degree field of view. Click image for larger view. (Chart derived from Starry Nights software screen shot.)

Click here to download a printer-friendly version of this chart.

The two donkeys are about as bright as the stars in the handle of the Little Dipper, so under dark skies should be faintly visible to the naked eye with the northern one the dimmest. The third star, Eta Cancri, is dimmer still. Its name, however, indicates that it, the Beehive, and other stars shown here are all part of the rather obscure constellation known as Cancer, the crab.

Look North in March 2013 – Oops, there’s a big hole in the sky!

Well, not really – but unless you live in an area with very dark skies, free of light pollution, you’re going to have a hard time seeing the faint stars above Polaris, the North Star, at this time of year. Here’s what our March north sky star chart looks like.

Our northern sky is quite dark above Polaris, but the Big Dipper is prominent in the northeast and serves as our primary guide to finding the North Star. Click image for larger view. (Prepared from a screen shot of Starry Nights software.)

Click here to download a printer-friendly version of this chart.

Notice the emptiness? The area labeled “Dark Hole?” Mind you, this is not a black hole – just an area of our sky that looks quite empty – unless your viewing location is free of light pollution and your eyes are thoroughly dark adapted. If you can see all seven stars of the Little Dipper, then you should see several stars in this area. But even then I doubt if you will be able to trace out the constellation which goes there. It’s known as Camelopardalis. My copy of Urania’s Mirror, published in 1832, says Camelopardalis consists:

. . . of 58 stars, but none larger than the fourth magnitude. . . .The Camelopard is an Abysinian animal, taller than the elephant, but not so thick. He is so named because he has a head and neck like a camel, and is spotted like a leopard; but his spots are white upon a reddish brown ground. The Italians call him giraffa. To Hevelius, who formed the constellation, he owes his celestial honors.

Ah, giraffe! Thank you, Italians. Here’s how he is pictured in full color on one of the constellation cards that came with Urania’s Mirror (The scan is © Ian Ridpath.)

Camelopardalis as depicted on the card from Urania’s Mirror, 1832. Notice the Pointer Stars of the Big Dipper are near the upper left and Polaris is just to the right of the giraffe’s head, so at this time of year the giraffe would appear upside down in our northern skies.

If you put him in the sky at this time of year his head would be down near Polaris. . . . Hmmm… the illustrator seems to have forgotten the spots mentioned in the text, and the animal’s neck got a bit longer than a camel’s. Ah well – while the 1830s had some advantages in terms of simplicity, I don’t think I would like to be trying to learn the night sky with Urania’s Mirror as my only guide.

Oh – but speaking of long necks, one of the things that has always fascinated me is some of the early attempts at astronomical telescopes and particularly the one in the following woodcut. This was an instrument built by Johann Hevelius in the mid-17th century at his observatory in Poland. The tube was about 150 feet long – befitting, in a strange way, for the man who put a giraffe in the northern sky!

Click image for larger view.
There was a logic to this giraffe-like telescope.
At the time a telescope’s lens could not bring the different colors of light to a single focus, so bright objects were always fringed with color and nothing was in really sharp focus. This negative effect, however, could be lessened by making the telescope’s focal length longer – so to get a really good telescope you had to go to these ridiculous extremes – which, of course, made it a nearly impossible telescope to use in any practical way.
Impressive to look at – difficult to aim and look through.
Fortunately the achromatic lens – combining two different types of glass – was invented and this reduced the problem considerably even in a relatively short telescope. We still use such achromatic lenses today ins mall refractor, though if you want to get a really sharp, color-free image you pay considerably more money for an apochromatic lens. Or, you listen to Newton who figured way back int he 1600s that the way around this was to design a telescope that used a mirror to collect the light rather than a lens. Trouble was, it took a long time to learn how to make mirrors that didn’t tarnish quickly when exposed to the night air. Nothings easy!
Now – about or “hole” in the northern sky. Get to a place where light pollution is at a minimum and it will fill with stars – relatively faint, but they are there. Just scan around with binoculars and you’ll find some even through the typical light pollution most people today are forced to endure. 

Update- March 5 – Outlook brightens for PanSTARRS!Events – March 2013: Get set for a real nice – BINOCULAR – Comet and more

NASA guide to PanSTARRS position and tail direction on different dates this month. This is NOT a prediction of tail length or comet brightness. It is likely tobe much shrter and fainter - but comets are full of surprises and so this still has the potential to be really nice.

NASA guide to PanSTARRS position and tail direction on different dates this month. This is NOT a prediction of tail length or comet brightness. It is likely to be much shorter and fainter – but comets are full of surprises and so this still has the potential to be really nice. (Click image for larger version.)

The latest indicators are that Comet PanSTARRS will put on a better show than anticipated just a week ago – as noted, comets are just not that predictable! – here’s a recent news item:

Observers in the Southern Hemisphere have been watching Comet PanSTARRS for weeks, but the Northern Hemisphere is due to get its first looks at one of the year’s most eagerly anticipated sky extravaganzas this week. And there’s good news for northerners: The up-and-down expectations for the cometary show are trending upward again.

March Observing Highlights  –

Comet PANSTARRS and its distant kin, the Zodiacal Light

First, let me stress Comet PanSTARRS is not likely to be nearly as bright as originally predicted – but it still should be a nice comet, especially when viewed with binoculars.  And remember – we have another due in November/December that should be much better. However, with comets we can only make educated guesses – they can – and have – surprised the experts over the years, sometimes under performing, sometimes over performing.

I’m linking this comet with the Zodiacal Light because both might be seen at their best on March 12 after sunset in the west. What’s more,  they are  both essentially dust reflecting sunlight,  presenting a related observing challenge, though they are radically different in size. March 12 may be the earliest time for a good look at Comet PanSTARRS in the early twilight – and it will be the last night in early March for the  Zodiacal Light which can be seen about 80 minutes after sunset for the first 12 days of March – after that the Moon will tend to wash out the Zodiacal Light until the last couple days of the month.

Quick Observing Guide:

  • to observe both comet and Zodiacal Light  at their best, hope for clear skies on March 12 – and some special comet luck 
  • to observe the Zodiacal Light  alone go out any evening during the first 12 days of March 2013 and look for it about 80 minutes after sunset.
  • to observe Comet PanSTARRS it may be visible – especially from low northern latitudes such as the southern US, as early as March 7 or 8th, but the week beginning March 12 will probably give the best opportunity for observers in mid-northern latitudes.

A comet is a “dirty snowball” that “melts” when it gets near the sun, giving off what can be a spectacular trail (tail) of tiny dust particles that reflect sunlight. When we think of a comet we are usually thinking of seeing one with such a tail.  And the Zodiacal Light? It’s tons of inter-planetary dust, much of it having accumulated over the years from many comets that eventually disintegrated as they made several trips around the Sun. And while your best views of Comet PanSTARRS will be when it’s near the Sun – but getting dark – your best view of the Zodiacal Light will be just as full darkness is arriving – about 80 minutes after local sunset.

The Zodiacal Light will be in a fixed position night after night – a huge, but very faint, light cone reaching from the western horizon and slanting up in the general direction of the Pleiades star cluster in Taurus  – Comet PanSTARRS will change position slightly each night, drawing away from the Sun. The Zodiacal Light is most certainly a naked eye phenomenon requiring a good view to the west and  skies that are largely free of light pollution in that direction.

The same basic requirements fit Comet PanSTARRS – you need a good view to the west with an unobstructed horizon, at least for the early – and probably best – views. While it may be visible to the naked eye, the best guess is this will be bets seen in binoculars. So by all means, break out the binoculars! You don’t need any thing special – ordinary, low-power ones will do, though if you have large astronomical binoculars, all the better.  And while you will be searching for the comet in the early twilight, do be careful. Wait until about 15 minutes after sunset before scanning the western horizon for it. At all cost, avoid looking with your binoculars at the sun, as that will seriously damage your eyes.

Yes, you are likely to hear that PANSTARRS is visible to the naked eye. Don’t get too excited, though, it’s visibility is a lot like that regular March visitor, the  Zodiacal Light – the numbers in reality don’t really add up. Thus the binoculars are highly recommended – even if its brighter than expected.

Great video guide to the comet from NASA

I read in Sky and Telescope this month that the Zodiacal Light is actually the second brightest “thing” in the Solar system.  Wow! Never prove that from my experience. I  have always found it elusive. I count myself lucky if I can see it at all!  But, of course, Sky and Telescope is right.  Here again there’s an important lesson relating to both the Zodiacal Light and a comet – the brightness they’re talking about is for a point object, but in our view of it, this light is spread out.

So when you hear the Zodiacal Light is beaten only by the Sun in brightness, you have to understand that this is determined by pretending all the light reflected from it was concentrated in a single spot – and it isn’t. It is spread out over a huge area of sky – widest near the horizon and getting narrower as it rises towards the Pleiades. For me it looks much like the Milky Way, only a bit fainter.

The same thing is true of a comet – but to a much lesser degree. That is, Comet PanSTARRS is fairly likely to reach magnitude 2 and if it does, well that’s as bright as the North Star, or most of the stars in the Big Dipper. But – and here’s the catch – that light will be spread out with much of it concentrated in the fuzzy head, but  some also appearing in the tail.

What’s more, as the comet draws away from the Sun it will almost certainly get fainter – and therein lies the crucial problem of seeing a comet at its best. What we are dealing with is a constantly changing set of variables. Generally speaking, the closer a comet is to the Sun, the brighter it is.  However, the closer it is to the Sun, the more it is competing with the lingering sun light. As the twilight deepens, the comet should stand out more – BUT, as the twilight deepens the comet is also getting lower in the sky and that means you’re looking at it through more atmosphere and that makes it appear dimmer.

So the joy – and frustration – of comet hunting is that how the comet looks to you will depend on your local weather, of course, but also exactly when you see it – how bright it is, how high it is, and how dark the sky is around it. That’s what makes viewing – and photographing – comets both fun and challenging.

So what’s the best bet for Comet PanSTARRS – for those in mid-northern latitude somewhere between March 7 and 20 probably about halfway in between. I plan to watch the weather closely from March 10th to 17th and take advantage of any clear evening to look for it. The farther south you are, the sooner it should appear at its best for you – the farther north,  the later in the month it will be at its best.

But remember – on a  clear night early in the month that you go comet hunting – hang around even if the comet is too low to see well – the Zodiacal Light should be best about 80 minutes after sunset when there is no – or little – interference from the Moon. (That means from March 1 to about March 12, 3013.)  If you see the Zodiacal Light – how well you see it depends largely on timing, local weather conditions, and the lack of light pollution.  In other words, it is not quite to finicky as the comet, but still a challenge.

Jupiter – King of the Winter Hexagon!

Wow! What a view to the south!

As the sky darkens on these March evening, don't hesitate to look due south for a wonderful view of Jupiter dominating the Winter Hexagon - thata rea of sky with more birght stars in it than any other! Click the image for a larger version. (Prepared from Starry Nights Pro screen shot.)

As the sky darkens on these March evening, don’t hesitate to look due south for a wonderful view of Jupiter dominating the Winter Hexagon – that area of sky with more bright stars in it than any other! Click the image for a larger version suitable for printing. (Prepared from Starry Nights Pro screen shot.)

The Winter Hexagon is one of my favorite asterisms encompassing a very rich area of sky contains eight very bright stars and that most recognizable of constellations, Orion.  But bright as these stars are, Jupiter will dominate them, outshining even Sirius, the brightest star for norther hemisphere observers. Take a look in that direction about an hour after sunset – in fact, you can’t hope but notice this brilliant area as you scan in the darkening even sky for the Zodiacal Light which shine faintly in a widening cone reaching from near the Pleiades to the western horizon.

And what a fabulous binocular sight!

Use your binoculars to:

  • Look for the fuzzy area in Orion’s sword  which hangs below his belt – the Great Orion Nebulae.
  • Look for the Hyades – the fabulous star cluster that makes up the “V” of Taurus and is just 150 light years away.
  • Look for the Pleiades – my favorite binocular target, a cluster of brilliant gem stone roughly 400 light years away.
  • And, of course, if you can hold them steady enough – brace against a pole, or the corner of a house – try to pick up one or more of the four bright moons of Jupiter.
The "V" of Taurus marks the Hyades cluster and the Pleiades are bit to the right as seen when looking south about 90 minutes after sunset this month.  Watch carefully over the course of the month and you will see Jupiter slowly change position moving towards Aldebaran, the bright star that marks the bull's eye. (Click for larger version. Prepared from Starry Nights Pro screen shot.)

The “V” of Taurus marks the Hyades cluster and the Pleiades are a bit to the right as seen when looking south about 90 minutes after sunset this month. Watch carefully over the course of the month and you will see Jupiter slowly change position moving towards Aldebaran, the bright star that marks the bull’s eye. (Click for larger version. Prepared from Starry Nights Pro screen shot.)

Oh – and I should add that Jupiter will have a real close call with a “young” crescent Moon on March 17, 2013. Exactly how close will depend on where you are, but for me on the East Coast of the US, the Moon will pass within two degrees of the bright planet and add to the fun of binocular observing on that night. They both will fit easily into the same binocular field of view!

Saturn now dominates the morning sky

Think of it as “coming attractions” if you’re not a morning person. Saturn crosses over into our late evening sky and by next month it will be quite easy t see at a reasonable hour.  For March 2013, however, it is primarily the dominant planet in the morning sky.

In fact, this is a rare month for planets – well, I should say planets are rare this month. Jupiter and Saturn are, for all practical purposes, the whole show – the other major planets being too near the Sun for easy viewing.

Our chart shows Saturn at  mid-month and midnight due southeast and about 23 degrees above the horizon. Spica – which is about half a magnitude dimmer than Saturn, will be about 18 degrees away. Be sure to look for the color difference. Saturn should appear creamy – maybe a tad yellow, while Spica is an icy blue.

Saturn and Spica at midnight in March 2013. (Prepared from Starry Nights Pro screen shot. Click image for larger version.)

Saturn and Spica at midnight in March 2013. (Prepared from Starry Nights Pro screen shot. Click image for larger version.)

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