Coastal Breeze News » Southern Skies http://www.coastalbreezenews.com Thu, 28 Aug 2014 15:35:22 +0000 en-US hourly 1 http://wordpress.org/?v=3.9.2 Just Horsing Around http://www.coastalbreezenews.com/2014/08/26/just-horsing-around/ http://www.coastalbreezenews.com/2014/08/26/just-horsing-around/#comments Tue, 26 Aug 2014 13:49:18 +0000 http://www.coastalbreezenews.com/?p=41010 SOUTHERN SKIES
By Mike P. Usher
usher34105@earthlink.net

Tonight, the eastern sky is dominated by the Great Square of Pegasus (the winged horse). The square forms the body of the horse while fainter stars form the neck and forelegs. The fairly bright, slightly orange star of Enif marks the muzzle. The asterism of the square is really quite easy to spot. If you don’t see it at first, think large; each side of the square is about 15 degrees on a side, so the entire asterism covers a big chunk of sky.

An interesting test of the quality of your sky can be done by counting the number of stars you can see inside of the square. If you can count a dozen or so, congratulations, you have a fine dark sky! On the other hand, observing from suburban skies, count yourself lucky to see any stars at all inside of the square. Only try this on a clear moonless night.

There are few deep sky objects visible with binoculars in Pegasus, the brightest being the globular star cluster of M15 near Enif mentioned in the previous column. Also located here is a cluster of five galaxies called Stephan’s Quintet that almost everyone has seen a photograph of but few can name. The photo appears in the famous move “It’s a Wonderful Life” in the scene where the angels are having a conversation; the galaxies serve as a stand in for heaven. Alas, Stephan’s Quintet is far beyond the range of binoculars and all but the largest amateur telescopes.

Tacked onto the rear of Pegasus is the fairly bright constellation of Andromeda. Technically speaking, the lower left star of the Great Square belongs to Andromeda and not Pegasus, although few people indulge in such hairsplitting. Most people just consider the star, named Alpheratz, shared equally between the two constellations. A galaxy that is within range of binoculars and even the naked eye resides in Andromeda. To spot it with your eyes, wait for a moonless night when Andromeda is higher in the sky; check out the accompanying chart for location.

As long as you have your binoculars out, see if you can find Uranus. The planet is rather farther than usual from us at the moment and is not quite visible to the naked eye, especially as it is close to the horizon. It’s dead easy to see with binoculars, though. The main problem is to identify which of the numerous stars in your field of view is really the planet. Currently, Uranus is in a region of the sky that is star poor, so it’s probably the brightest object in your field of view.

See you next time!

 

Mr. Usher is a Director of the Everglades Astronomical Society which meets the second Tuesday of the month Sep. thru May at 7:00PM in the Norris Center, Cambier Park, Naples. E-mail: usher34105@earthlink.net


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Getting Your Goat http://www.coastalbreezenews.com/2014/08/11/getting-your-goat/ http://www.coastalbreezenews.com/2014/08/11/getting-your-goat/#comments Mon, 11 Aug 2014 19:11:57 +0000 http://www.coastalbreezenews.com/?p=40821 SOUTHERN SKIES
By Mike P. Usher
usher34105@earthlink.net

Capricornus, the goat, is the second faintest constellation in the zodiac after Cancer, but it is rather easier to pick out than its near neighbor Aquarius. Capricornus is framed by several modestly close pairs of stars which are quite noticeable once initially located. This constellation is usually referred to as a goat, but classic drawings of Capricornus show a sort of hybrid creature with goat forequarters and a fishlike tail. This makes Capricornus a member of “the sea” — a term covering a large patch of sky which contains constellations with a water theme. Aquarius (the water carrier) and Piscis Austrinus (southern fish) are two other members of the sea shown on tonight’s chart, but there are several others.

As mentioned previously, nearby Aquarius is a bit harder to pick out of the sky than Capricornus even though the stars are a tiny bit brighter; the problem is they are more spread out. Aquarius has a number of deep sky objects to fascinate the advanced stargazer, but only a few are visible with binoculars. Of these, the globular cluster M2 is one of the best and brightest in the sky. The cluster spans a bit less than half the apparent width of the full Moon and is rated at magnitude 6.5. Very similar to M2 is the nearby M15 (actually in Pegasus), which may be easier to find as it is fairly close to the bright star Enif.

A temporary visitor to Aquarius is Neptune, although it’s been there four years already and it will be another eight before it finally moves into Pisces. Neptune is the slowest and furthest planet from the Sun, taking something like 164.8 years to complete its orbit. About magnitude 8, Neptune is easy to see with a pair of binoculars — the problem is identifying it. A dedicated observer with a computerized star chart should be able to locate it among numerous similarly dim stars. This accounts for its late discovery date of 1846. In fact, Neptune’s existence was predicted before it was seen based on Uranus’ orbital peculiarities. A dedicated telescope search then revealed the planet.

See you next time!

Mr. Usher is a Director of the Everglades Astronomical Society which meets the second Tuesday of the month Sep. thru May at 7:00PM in the Norris Center, Cambier Park, Naples. E-mail: usher34105@earthlink.net

 

 

 


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The Summer Triangle http://www.coastalbreezenews.com/2014/07/22/the-summer-triangle/ http://www.coastalbreezenews.com/2014/07/22/the-summer-triangle/#comments Tue, 22 Jul 2014 19:22:38 +0000 http://www.coastalbreezenews.com/?p=40158 SOUTHERN SKIES 
By Mike P. Usher 
usher34105@earthlink.net

We talk about the Summer Triangle consisting of Vega, Altair and Deneb from time to time and once again it is high in the east. This asterism is a relatively recent invention popularized by Sir Patrick Moore about 60 years ago.

The three stars of the Summer Triangle are buried deep in the Milky Way, and their constellations are rich in Deep Sky objects. But before looking for any of them, examine the shape of the Milky Way itself. If you are at a dark sky site, you can’t help but notice the Milky Way is not a continuous stream, but is in fact rather irregular in shape. In particular, between Cygnus and Aquila there is a dark streak largely devoid of stars. This is the Great Rift — not really a starless region but a vast dust cloud that blocks the starlight behind it.

Rather than hunt for a particular Deep Sky object with your binoculars, lay down on a lawn chair with them and sweep the sky along the length of the Milky Way. There is nothing like the thrill of discovery! Most of the Deep Sky objects seen in this area of the sky are known as open or galactic clusters. These are groups of stars of perhaps a dozen to several hundred that were born at nearly the same time and are still associated with each other. Our Sun was born in such a cluster long ago, now dispersed. Open clusters are short-lived objects perhaps lasting no more than 100 million years before gravitational forces from the rest of the galaxy pry them apart. Somewhere in the sky tonight are the long lost siblings of the Sun.

Such a sibling has just been found! It’s marked in the chart tonight by a large circle just above Vega. It’s only a 6.5 magnitude star, just below naked eye visibility, but easy to spot with binoculars. The star (called HIP 87382 by one popular catalog) is slightly larger than our Sun and has no known planets — but their possible existence has not been ruled out. The things that identify the star as related to us are that it has exactly the same chemical composition as our parent star and is the same age. At 110 light years the star is amazingly close. Members of our birth cluster have had time to be scattered across half the galaxy.

See you next time!

 

Mr. Usher is a Director of the Everglades Astronomical Society, which meets the second Tuesday each month at 7 PM in the Norris Center, Cambier Park, Naples


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The Glories of Sagittarius http://www.coastalbreezenews.com/2014/06/27/the-glories-of-sagittarius/ http://www.coastalbreezenews.com/2014/06/27/the-glories-of-sagittarius/#comments Fri, 27 Jun 2014 13:07:07 +0000 http://www.coastalbreezenews.com/?p=39901 SOUTHERN SKIES 
By Mike P. Usher 
usher34105@earthlink.net

Last column, we gave only a scant glance at this most interesting spot in the sky, so with your indulgence we shall return to it.

First notice the nearly full Moon in the sky — how could you miss it? Tonight, it sits quite low in the sky and will not rise much higher. This is because the Moon moves along the ecliptic, and the ecliptic itself is rather tilted, low in the summer sky and high in the winter.

Why does the Moon follow the ecliptic at all? The major planets must as Solar System dynamics constrain them to a narrow band on either side of the ecliptic, but no such constraint should apply to the Moon. Orbits of other planets’ satellites lie on their primaries equator with a few minor exceptions, but not the Moon. It is a mystery, although presumably it has to do with how the Moon was formed.

The Moon sits in Sagittarius this evening, but you may wish to wait a couple of nights until the Moon is out of the way so you can view the constellation more easily. Can you make out the teapot shape embedded in the constellation? It is an unmistakable asterism once you see it for the first time.

When I was a boy I looked at Sagittarius for hours and never saw it as the map I was using omitted it, but it was instantly obvious once someone pointed it out to me. On a really dark night, the star clouds in Sagittarius seem to hover above the teapot spout like steam. The ancient Greeks, having no known experience with teapots, saw instead a centaur shooting a bow with the arrow aimed at the nearby Scorpius.

Sagittarius is almost literally stuffed with fascinating binocular objects. Rather than find a specific one, take a few minutes and scan the Milky Way in a systematic manner. In 10 minutes, you will find 10 amazing objects.

When you have a moment, have a look in Scorpius and locate the star Dschubba. In 2000, after being well behaved for all of recorded history, it suddenly became a variable star only slightly less bright than Antares. Dschubba has dimmed since then, but it remains brighter than it was before 2000. Another outburst may happen at any time.

See you next time!

 

Mr. Usher is a Director of the Everglades Astronomical Society, which meets the second Tuesday each month at 7 PM in the Norris Center, Cambier Park, Naples.


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Reward Yourself for Patience http://www.coastalbreezenews.com/2014/06/13/reward-yourself-for-patience/ http://www.coastalbreezenews.com/2014/06/13/reward-yourself-for-patience/#comments Fri, 13 Jun 2014 09:50:57 +0000 http://www.coastalbreezenews.com/?p=39582 SOUTHERN SKIES
By Mike P. Usher
usher34105@earthlink.net

Proud owner Jackie Richards hugs her new 10 inch dobsonian at the 2013 Winter Star Party in the Florida Keys

Proud owner Jackie Richards hugs her new 10 inch dobsonian at the 2013 Winter Star Party in the
Florida Keys

Careful readers may notice this is the 100th column of Southern Skies. If you have been reading the columns and studying the sky for the past two years, now is the time to reward yourself – because you know the sky better than almost everyone. It’s time to buy your first telescope; but do careful research first. If you do not you will buy the wrong telescope. It is difficult to buy the right telescope, but it is easy to point out what the wrong one will be; it’s the one you will not use. Too heavy, too small, too cheap, too hard to use; anything that will prevent you from being motivated to drag it outside on a regular basis.

It is also important to keep your expectations modest – no telescope made will show you the spectacular details and colors posted on the internet. Those photos are all time exposures and many are artificially colored; usually there are good scientific reasons for this but the fact remains – you can’t see those details with your eyes – telescope or not. Still, with the right telescope, the surface of the Moon will be as familiar as your backyard. The rings of Saturn, surface of Mars, clusters containing a million stars, birthplaces of suns, dying stars and hundreds of galaxies are within your reach.

Although it’s no substitute for doing your own research, I think most beginners will find that an 8 (200mm) to 10-inch (250mm) dobsonian telescope will fit their needs. Smaller ones aren’t worth the time or money while larger ones are horrendously expensive and pose logistical problems. Two kinds of people won’t be happy with this choice: budding astrophotographers and people with small condos/small cars or both. Astrophotographers are in a class by themselves and we can ignore them for now. The other group is faced with a choice, find room somehow for a big dobsonian or purchase an 8 or 10-inch Schmitt-Cassegrain telescope (SCT). The big advantage of an SCT is that it takes up less than half the storage space a big dobsonian does; the disadvantage is it costs three times as much because SCT’s are usually computerized.

An 8-inch dobsonian costs about $500 on the Internet. Throw in another eyepiece, a magnifying finder and collimation tools (an absolute necessity) and you are looking at around $800. A 10-inch outfitted the same way will total less than $1,000. An 8-inch SCT will cost you about $1600 – without accessories. The dobsonian prices do not include any optional electronics, but you don’t need any – trust me! Email me and I can send you a list of reputable vendors and maybe some additional information. If this is out of your price range binoculars are the preferred option (see previous column). Whatever you do, don’t purchase a telescope from a department store – you will regret it.

 

Mr. Usher is a Director of the Everglades Astronomical Society, which meets the second Tuesday each month at 7 PM in the Norris Center, Cambier Park, Naples.

 


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Use Those Binoculars! http://www.coastalbreezenews.com/2014/06/03/use-those-binoculars/ http://www.coastalbreezenews.com/2014/06/03/use-those-binoculars/#comments Tue, 03 Jun 2014 12:46:58 +0000 http://www.coastalbreezenews.com/?p=39369 SOUTHERN SKIES
By Mike P. Usher
usher34105@earthlink.net

Even the slightest optical aid reveals new wonders unseen by the naked eye. The most affordable aid are binoculars; almost any size and model number will work well for you. Binoculars will show you the moons of Jupiter, the crescent phase of Venus, the larger lunar craters, every other planet in the Solar System, all 110 Messier objects (albeit with some difficulty), a number of binary stars and a handful of asteroids. Binoculars are generally the best instrument to use when scanning the vistas of the Milky Way and observing the larger star clusters like the Pleiades and Hyades. Even after you have upgraded to a telescope your binoculars will be a constant companion. Starting around $70, you just can’t beat them!

When buying optical equipment it’s easy to get all wrapped up in various number games, for binoculars you only need to pay attention to two – or three if you wear glasses. Binoculars are described using terms such as 7×35 or 10×50. The first number refers to the available magnification and the second is the size of the objective lens in millimeters. Larger objectives mean brighter images but greater weight and higher cost. Conversely smaller objectives mean slightly dimmer images but lesser weight. Weight is a big deal with binoculars, heavy binoculars just can’t be held steady enough to observe the heavens comfortably; more on this later.

The third number that eyeglass wearers need to know is something called eye relief. This is the distance your pupils can be from the eyepiece and still see the whole field of view. Although the focuser can accommodate near and farsighted users it’s just a hassle to keep removing your glasses all night long. Also if the user has astigmatism the glasses must remain on when using binoculars. Fifteen millimeters of eye relief is ok – twenty is better.

A great many people can’t hold even 7×35′s steady enough to observe stars; there are two solutions, purchase binoculars with stabilizers or the better and probably cheaper option, a tripod. Binoculars meant for stargazing have a threaded insert meant for attaching them to an accessory bracket which then is fitted to a tripod.

In general for a beginner, a 10×50 size will be the first choice especially when combined with a tripod. Such binoculars are often advertised as coming with roof, porro, or BAK-4 prisms. Don’t worry too much about the differences in prisms – each have their own advantages – but all will give fine views of the heavens. Once again don’t get all caught up in the numbers, I have a 60 year old pair of 7×35′s my grandfather owned that still gives good service to this day.

See you next time!

 

Mr. Usher is a Director of the Everglades Astronomical Society, which meets the second Tuesday each month at 7 PM in the Norris Center, Cambier Park, Naples.


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Arc to Arcturus http://www.coastalbreezenews.com/2014/05/19/arc-to-arcturus-2/ http://www.coastalbreezenews.com/2014/05/19/arc-to-arcturus-2/#comments Mon, 19 May 2014 12:47:15 +0000 http://www.coastalbreezenews.com/?p=39050 SOUTHERN SKIES
By Mike P. Usher
usher34105@earthlink.net

Very high in the east lies Arcturus, an orange giant star that is the brightest star in the sky this evening. Arcturus is also the brightest star in the Sun’s general neighborhood; it is about 170 times more luminous than our home star. If you are having a bit of trouble finding it remember the phrase “arc to Arcturus,” which means follow the arc of the Big Dipper’s handle until you reach the bright orange Arcturus.

Arcturus is the brightest star in the constellation of Boötes, the herdsman. In ancient times, the star was a couple of degrees closer to the center of the constellation. This is because Arcturus has what is called a large proper motion; it’s slowly moving southwards and a little east – but not fast enough to be noticed in a single lifetime.

Tonight there are a number of interesting globular clusters within range of your binoculars and one, the Great Cluster in Hercules, is just within the possibility of naked eye viewing. If you see it with the naked eye or binoculars you might compare it with the even larger Omega Centauri mentioned in a previous column. Although smaller than Omega Centauri the Great Cluster has the advantage of rising much higher in our sky thus giving the better view. There are about 300,000 stars in the Great Cluster, but it takes a large telescope to see individual ones. Through binoculars it looks like a perfectly spherical ball of fog, fading towards the edges.

The fairly nearby M3 is probably too dim to make out with the naked eye, but is easy to see with binoculars if you take care to locate the object carefully. It’s actually larger and brighter than the Great Cluster – but being farther away from us it winds up dimmer. While you have your binoculars in hand check out M5 in the nearby constellation of Serpens. Also a large globular cluster, it may have as many as 500,000 stars in it, but most estimates are smaller, perhaps “only” 100,000 stars. Like the other two clusters mentioned, only fairly large amateur telescopes can make out individual stars.

It’s important to draw a distinction between globular clusters and open clusters (also called galactic clusters). A typical globular cluster is roughly spherical, contains many tens or hundreds of thousands of stars and is maybe eight billion years old. They also are well scattered across the sky. Open clusters, on the other hand, contain tens to hundreds of stars, are irregularly shaped and usually only a few million years old. Open clusters tend to be found predominately within the band of the Milky Way.

See you next time!

 

Mr. Usher is a Director of the Everglades Astronomical Society, which meets the second Tuesday each month at 7 PM in the Norris Center, Cambier Park, Naples.


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Southern Cross Over Marco http://www.coastalbreezenews.com/2014/05/01/southern-cross-over-marco/ http://www.coastalbreezenews.com/2014/05/01/southern-cross-over-marco/#comments Thu, 01 May 2014 13:26:50 +0000 http://www.coastalbreezenews.com/?p=38700 SOUTHERN SKIES
By Mike P. Usher
usher34105@earthlink.net

Did you see the Lunar eclipse last month? We scored a reasonably cloud free night and everyone got at least a decent view. If you missed it, don’t worry. You will have another chance this coming October and twice more in 2015. A group of four consecutive lunar eclipses viewable from North America is modestly rare – the last time was in the 1990s.

This time of year is the annual spot the Southern Cross challenge. What is needed is a good clear night and an unobstructed view of the southern horizon – preferably a view of the ocean. Altitude helps too, even something as short as a ladder. The top three stars of the Southern Cross are fairly easy given a clear night; the real tough one is the bottom star, Acrux. It is one of the brightest stars in the sky but the proximity of the horizon and the thick air near it dim it to near invisibility.

A much easier target is the giant globular cluster of Omega Centauri; in the chart tonight is located just above the “a” in Centaurus. Dimly visible to the naked eye as a fuzzy spot, it is actually the largest globular cluster in our galaxy and one of the largest in this corner of the universe. It contains perhaps one million stars spread over the sky in an area considerably larger than the apparent size of the Moon. (It’s actual size is about 180 light years across.) It’s fairly easy to see the ball of stars in binoculars and in a large telescope it’s breathtaking.

For naked eye observers, tonight notice that the constellation Centaurus is low in the south. Not a particularly bright constellation, Centaurus has no competition from nearby bright stars so it is relatively easy to find – just look due south and there it is! Given that Centaurus is an ancient Greek invention, an astute observer might wonder how the Greeks could have possibly seen it; from Athens today perhaps only two or three most northerly stars in it are visible. The answer is that in ancient times Centaurus was higher in the sky. In fact, it was nearly the same height as we see it today in much more southerly Marco Island. The answer is that precession of the equinoxes has rotated the heavens slightly since that far distant time.

 

See you next time!

 

Mr. Usher is a Director of the Everglades Astronomical Society, which meets the second Tuesday each month at 7 PM in the Norris Center, Cambier Park, Naples.


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Return of the Ringed World http://www.coastalbreezenews.com/2014/04/23/return-of-the-ringed-world/ http://www.coastalbreezenews.com/2014/04/23/return-of-the-ringed-world/#comments Wed, 23 Apr 2014 17:43:51 +0000 http://www.coastalbreezenews.com/?p=38426 SOUTHERN SKIES
By Mike P. Usher
usher34105@earthlink.net

Now that we stand on the doorstep of May, the days are longer and the nights become cloudier. Usually the clouds are gone after midnight, but that is too late for most casual stargazers; a good compromise is 11 p.m. when the clouds start breaking up. Perhaps you can sneak some stargazing in when you take the dog out for a late evening trip.

Saturn returns to the evening sky this month and is well up by 11p.m. Saturn is a magnificent sight in a small telescope; at about 30x to 50x magnification the rings appear. This year, the rings are strongly tilted towards Earth making Saturn somewhat brighter than last season. The rings are well beyond the reach of standard binoculars, but Saturn’s giant satellite, Titan, is visible in 9x50s Look for a 9th magnitude point just to the left of Saturn. These instructions are only valid for the 2nd of May – Titan moves!

Saturn will be residing in the constellation Libra (the scales) for the rest of the year; Libra is the only zodiacal constellation that does not represent a living creature. Libra has a somewhat mixed history as a separate constellation. The Greeks tended to think of the stars of Libra as the scorpion’s claws while the Romans preferred to split it off as a pair of scales. It is represented in the sky as a quadrilateral of medium-bright to dim stars that requires a fairly dark sky to easily see it.

The star in the upper left of the quadrilateral, Zubeneschamali (I love that name), is the center of two minor mysteries. Ancient observers remarked it was the only star in the sky that was greenish in color and also stated it was brighter than the nearby Antares! Three hundred and fifty years later it was stated that Antares and Zubeneschamali were of the same magnitude. It is unclear if Antares has grown brighter or Zubeneschamali has become dimmer; today Antares is over 1.5 magnitudes brighter. As far as color is concerned, modern observers mark Zubeneschamali definitely as blue. (It should be noted that at magnitude 2.6 it shows little, if any, color to the naked eye).

See you there!

 

Mr. Usher is a Director of the Everglades Astronomical Society, which meets the second Tuesday each month at 7 PM in the Norris Center, Cambier Park, Naples


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The Moon Puts on a Good Show http://www.coastalbreezenews.com/2014/04/09/the-moon-puts-on-a-good-show/ http://www.coastalbreezenews.com/2014/04/09/the-moon-puts-on-a-good-show/#comments Wed, 09 Apr 2014 14:37:45 +0000 http://www.coastalbreezenews.com/?p=37728 SOUTHERN SKIES
By Mike P. Usher
usher34105@earthlink.net

During the early morning hours of Apr. 15, the moon will undergo a total lunar eclipse. Unlike its distant cousin the solar eclipse, a lunar eclipse is perfectly safe to look at as long as you please.

A lunar eclipse happens when the moon passes through earth’s shadow; this only happens at a full moon, and the moon’s orbit crosses the ecliptic (hence the origin of the word “ecliptic”). Another way to express this is to say the centers of the earth, moon and sun temporarily lie in a straight line or nearly so; astronomers speak of this alignment as syzygy – a mostly useless word but great in a Scrabble® game!

The eclipse begins at 12:53 a.m. as the moon moves into the penumbra, a region of partial shadow. This is a truly under-whelming event, so don’t bother to wake up for it. The real action begins at exactly 1:58:19 a.m. when the moon begins to enter the umbra; the region of dense shadow. With a small telescope or steady binoculars you will be able to see earth’s shadow sweep across the lunar surface. Totality comes a little over an hour later at 3:06:46 a.m.

If the earth had no atmosphere the moon would be invisible at this point. However, sunlight is refracted around our planet by our thick layer of air and the moon appears red in color. The color can vary from an almost invisible brick red to a bright red with the lighter shade being most common. Essentially, the moon is illuminated by all the sunrises and sunsets occurring on our home planet. The color is impossible to predict in advance as it is heavily dependent on the worldwide weather. Usually for the very dark brick color something odd must be happening on earth, like a major volcanic eruption. (Think Krakatoa.)

At 4:24:34 a.m. the moon begins to exit the umbra, and is completely free of the umbra at 5:33:02 a.m. Officially, the eclipse is over at 6:37 a.m. when the moon clears the penumbra.

If you get up mid-eclipse the moon may be a bit difficult to locate at first. Fortunately, the moon will lie very close to the bright star Spica and not far from the even brighter Mars.

See you there!

 

Mr. Usher is a Director of the Everglades Astronomical Society, which meets the second Tuesday each month at 7 PM in the Norris Center, Cambier Park, Naples.


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Time for Mars http://www.coastalbreezenews.com/2014/03/26/time-for-mars/ http://www.coastalbreezenews.com/2014/03/26/time-for-mars/#comments Thu, 27 Mar 2014 00:31:22 +0000 http://www.coastalbreezenews.com/?p=37573 SOUTHERN SKIES
By Mike P. Usher
usher34105@earthlink.net

Mars is now the third brightest object in the evening sky. Only Jupiter and the star Sirius beat it out. Reddish Mars is located near the blue white star Spica, and together the two make an interesting color contrast; also nearby is the bright star Arcturus – an orange giant.

Mars is nearing opposition, which it will reach on April 8. When any outer planet is located 180 degrees from the Sun it is said to be at opposition (that is it’s opposite the Sun). The importance for stargazers is that the planet rises at the same time the Sun sets and is visible all night long. Also, opposition is the time the outer planet is nearest to Earth and appears largest and brightest.

In the case of Mars, not all oppositions are created equal; the planet has a rather elliptical orbit and some oppositions are simply better than others as the distance from Earth can vary quite a bit. This particular one is perhaps about average or a bit less. The closest oppositions come in intervals of 15 or 17 years and the best ones always occur in the summertime. You may remember the best opposition of recent times was in August of 2003 when Mars got a considerable amount of press. That particular opposition also spawned a hoax e-mail which annually appears every August promising that Mars will look as large as the Moon. This is flatly impossible.

Although the best oppositions are widely spaced, Mars does return to opposition every 780 days on average – a time span known as the synodic period. Strictly speaking the synodic period is the time it takes any three bodies (typically Earth, Sun and a planet) to return to the same relative positions. Every planet in the Solar System (and the Moon) have their own characteristic synodic period: the Moon 29.5 days; Jupiter 13 months; and Saturn 54 weeks, for example. Please note the synodic period is not the same as an orbital period and is actually a combination of Earth’s and a planet’s motion around the Sun.

On March 22 at Collier-Seminole State Park is a Star Gazing Party open to the general public. Several Everglades Astronomical Society club members and I will be there with telescopes and a park ranger from Big Cypress will give an interpretive presentation. I have heard his presentation before and he does put on a good show! Activities begin at 8 PM. Admission is $4 per car. In case of poor weather we will try again on March 23.

 

See you there!

 

Mr. Usher is a Director of the Everglades Astronomical Society, which meets the second Tuesday each month at 7 PM in the Norris Center, Cambier Park, Naples.


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Moon over Marco http://www.coastalbreezenews.com/2014/03/11/moon-over-marco/ http://www.coastalbreezenews.com/2014/03/11/moon-over-marco/#comments Wed, 12 Mar 2014 00:41:32 +0000 http://www.coastalbreezenews.com/?p=37118 SOUTHERN SKIES
By Mike P. Usher
usher34105@earthlink.net

We do not often talk about the Moon in this column as it usually wipes the stars from the sky when it is present – particularly when it is nearly full. However the Moon is an interesting object in its own right and provides endless hours of entertainment for small telescope owners. In fact it is about the only heavenly object a department store telescope provides a decent view of.

It is shocking that so many misconceptions about our Moon exist; a small but significant percentage of people do not know that the Moon is plainly visible during the day nor that during some nights it is invisible. This is a consequence of its orbit around the Earth; naturally it must spend half of the time on the daylight side of our planet. Another misconception is that there is a “dark” side of the Moon. All parts of the Moon receive their fair share of solar illumination; at any given moment exactly half of the Moon is lit regardless of what phase we see down here on Earth. There is a “far side” of the Moon that we can never see from our vantage point since the Moon always keeps one side facing us, but it has been well mapped by space probes.

A moment ago it was stated the Moon orbits around the Earth; technically speaking this is not exactly true; what happens is the both the Earth and Moon revolve around their common center of gravity. While the Moon moves in a large orbit some 238,000 miles in radius, the Earth moves in a tiny circle only 3,000 miles in radius once every 28 days.

What is even stranger, and a lot harder to visualize, is the Moon does not “go around” the Earth in a traditional manner. From the point of view of someone standing on the Sun all satellites orbit their planets from west to east say, and at some point reverse their direction and complete the circle around the planet from east to west – fairly logical when you sit and think about it for a moment. All satellites except the Moon that is. The Moon never reverses direction! In fact it behaves much as a planet does; from the point of view of someone on the Sun the Moon circles the Sun(!) but in a series of twelve shallow waves plus the beginning of a thirteenth wave each year. (The waves are caused by the presence of the Earth).

If you do not understand all this, do not feel badly, it took humans at least five thousand years to work this out. We will return to the Moon in about two months; it’s scheduled to put on a good show during the early morning hours of April 15th.

See you next time!

 

Mr. Usher is a Director of the Everglades Astronomical Society, which meets the second Tuesday each month at 7 PM in the Norris Center, Cambier Park, Naples.

 


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The Zenith http://www.coastalbreezenews.com/2014/02/21/the-zenith/ http://www.coastalbreezenews.com/2014/02/21/the-zenith/#comments Fri, 21 Feb 2014 19:36:32 +0000 http://www.coastalbreezenews.com/?p=36739 SOUTHERN SKIES
By Mike P. Usher
usher34105@earthlink.net

Every now and then instead of facing a particular point of compass, it’s fun to look straight up — technically called the zenith. Looking up at the zenith has a couple of advantages over other directions: the sky becomes darker, and there is less atmosphere to absorb light so the stars tend to be brighter. The major difficulty is the human body is not well designed to spend an extended period of time staring straight up. Soon your neck starts hurting, and if you move suddenly, you could get dizzy and trip over something. It’s even worse if you use binoculars. Fortunately, a simple solution is close at hand; reclining chairs used around pools are the perfect stargazing accessory here.

Tonight, too-bright-to-miss Jupiter dominates the zenith and indeed the entire sky. It’s the only planet in the sky at the moment although Mars pops up in the East about 10 PM with Saturn following shortly after midnight. Now is the perfect time to whip out your trusty binoculars, and see Jupiter’s four bright satellites. Ranging from just slightly smaller than our own Moon to larger than the planet Mercury, the Galilean satellites are easy to spot with just a small pair of firmly-held binoculars. Indeed, all would be bright enough to see with the naked eye were it not for the overwhelming glare of Jupiter. Occasionally, there are reports of very rare people who can spot one (probably Ganymede) without optical aid.

Jupiter is within the borders of Gemini, the twins where the matching pair of Castor and Pollux form the heads of the stick-figure twins. Pollux is just a bit more luminous than Castor, but reports from ancient times indicate that Castor was the brighter star. It is uncertain if there was a mistake made or if there really has been a change. Several other changes in the sky might have occurred in the last few millennia. For example, the nearby (but not on tonight’s chart) Pleiades are almost universally known as the “seven sisters,” but only six stars are plainly visible to the unaided eye.

Now might be a good time to try and pick out the ridiculously faint constellation of Cancer, the crab. The brightest star in this constellation is only magnitude 3.5, while the Praesepe star cluster within it reaches 3.1. Without a doubt no constellation would have been placed here in ancient times were it not for the fact Cancer occupies a position along the ecliptic — the apparent path the Sun takes during the course of a year. The ecliptic was important to the ancients for several reasons; they must have believed every spot along it deserves it’s own constellation if for no other reason than to provide a convenient marker.

 

See you next time!

Mr. Usher is a Director of the Everglades Astronomical Society, which meets the second Tuesday each month at 7 PM in the Norris Center, Cambier Park, Naples.


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The Love Planet http://www.coastalbreezenews.com/2014/02/07/the-love-planet/ http://www.coastalbreezenews.com/2014/02/07/the-love-planet/#comments Sat, 08 Feb 2014 00:12:53 +0000 http://www.coastalbreezenews.com/?p=36387 SOUTHERN SKIES
By Mike P. Usher
usher34105@earthlink.net

Now that Valentine’s Day is upon us, it might be a good time to check out Venus, the namesake of the Goddess of Love. It might be mentioned in passing that Venus, the mythological being, was not exactly the goddess of love, but was solely the goddess of erotic love — not quite the same thing. Venus the planet, while beautiful to observe, is actually a fairly good approximation of Hell, with its 900 degree surface temperature, sulfurous smell and crushing air pressure. All this is due to the enormous quantities of carbon dioxide present in its atmosphere. Earth has roughly the same amount of carbon as Venus, but here it’s locked up in rocks, such as limestone, and plants.

Those of you that have been following the heavens will have noticed that Venus has vanished from the evening sky; it has crossed between us and the Sun, and has emerged into the morning sky where it will remain until September. The accompanying chart is for 6AM Valentine’s Day. This presents an opportunity to see Venus in broad daylight. Simply keep an eye on Venus as the Sun rises — a glance every minute or so will suffice.

Last time, we talked about the rich area of the sky about Orion. Now, Venus is near the only area of the sky that surpasses the great hunter, the Sagittarius, or Scorpius region. On the chart this morning, we have only the tail of Scorpius but the whole constellation of Sagittarius. This constellation is almost literally stuffed with interesting binocular objects. In fact, there are more Messier objects here than any other constellation. Sweep the entire area very slowly with your binoculars.

You might think it odd to be talking about summer constellations here in mid-winter, but in fact your favorite constellation is visible 10 or 11 months a year. It is just a question of when. So-called summer and winter constellations are classed according to their visibility during early evening hours; the earth continues to rotate as we sleep bringing additional constellations into view. Thus, by early morning, out-of-season constellations are clearly in view. Only the 10- or 15-degree wide band centered on the Sun is blotted out on any given night.

See you next time!

 

Mr. Usher is a Director of the Everglades Astronomical Society, which meets the second Tuesday each month at 7 PM in the Norris Center, Cambier Park, Naples.

 


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Can You See the “G”? http://www.coastalbreezenews.com/2014/01/29/can-you-see-the-g-2/ http://www.coastalbreezenews.com/2014/01/29/can-you-see-the-g-2/#comments Wed, 29 Jan 2014 14:16:11 +0000 http://www.coastalbreezenews.com/?p=35990 SOUTHERN SKIES
By Mike P. Usher
usher34105@earthlink.net

Here on Marco, the constellation Orion rides much higher in the sky than our northern visitors are used to. This allows the bright stars to really shine out with their full brilliance. Tonight, the chart depicts a close-up of this fascinating area of the sky.

The first thing a casual stargazer should notice is how the bright stars in this constellation are all very blue — with one huge exception, Betelgeuse. This star, in the upper left of the constellation, is a red supergiant; despite the name, it looks rather closer to a deep orange color. Hubble photographs show a disk that is red with a yellow spot near the center. There is considerable debate in scientific circles as to exactly what causes this. Betelgeuse is one of two stars that are both near enough and large enough to show a visible disk but only to space-based Hubble.

If you own a pair of binoculars, the area in and around Orion is something of a paradise. In particular, notice the Great Orion Nebula, so bright that it is even visible to the naked eye in suburban skies. At a dark sky viewing sight, the nebula looks like a fat fuzzy star. With binoculars, the nebula is clearly visible as a glowi

ng cloud. Interestingly it glows for the same reason a fluorescent light glows. Stars in its heart emit copious quantities of UV light that causes the oxygen in the nebula to emit a greenish glow. Some observers claim to spot the green color with binoculars although that is hard to believe. In a large amateur telescope, the color is easily evident.

While you have the binoculars out, see if you can locate the nearby M78 nebula and the brighter Cone Nebula. The second most well-known nebula in the area is the famous Horsehead Nebula, just a little south of Alnitak. Invisible to binoculars and almost all telescopes, it is primarily a target for photography. Probably no general interest book on Astronomy is missing a photograph of the Horsehead.

Although this week’s chart does not clearly show it, Orion can be used as a pointer towards other constellations, a little like the Big Dipper. An imaginary line drawn from Rigel through Betelgeuse points in the general direction of Gemini. Drawn the opposite direction, the line points to the center of Eridanus. A line extended downwards from the belt stars indicates the direction of Sirius, and extended upwards indicates Aldebaran. Drop due south, and you will reach Lepus the hare. Orion’s shield faces Taurus the bull.

See you next time!

 

Mr. Usher is a Director of the Everglades Astronomical Society, which meets the second Tuesday each month at 7 PM in the Norris Center, Cambier Park, Naples.


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