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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.

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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One Response

  1. Reblogged this on Fondazione M.

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