Notes From The Lawnchair
Winter Lawnchairing, Without Winter!
Too short! That's the only conclusion the Lawnchair and I can come up with for an often fly-by summer. But as we prepare to move the clocks back this month, we're all too aware of the inevitable onset of winter's frigid temperatures. Ice and snow are not too far away. But, until then, there is still a chance to see some of winter's finest jewels before the Lawnchair gets buried in that white fluffy stuff!
The big show and always a major visual treat each winter is the Great Nebula in Orion. Using your eyes alone to locate this stellar nursery, begin at the hunter's belt and look below that to the three diagonally oriented dim stars that would be his scabbard (the sheath that the hunter stores his sword in when not slicing up his foes). The middle star of this group is not actually a star but, rather, a foggy little patch of gas and dust we know as M 42, the Orion Nebula. In binoculars, it presents as a ghostly cloud with a definite brightening at its core.
In a quality telescope, adding more magnification, the center can be resolved into four, bright blue burning, stellar youngsters. Relatively speaking. Known as the Trapezium, it is imbedded in the heart of the nebula. A sort of stellar nursery, it encapsulates this group of brand new stars, all shrouded within this area of gas and dust clouds which disguises itself as the middle star in Orion's scabbard. It is estimated that these stars are just a few million years old, relative babies considering the age of the neighboring stars in their immediate proximity, which come in at several billion years old. Even in binoculars, the nebula is awe inspiring. In deep sky instruments, words alone cannot describe the feeling one gets when viewing this uncontested jewel of the winter sky.
The other noted sights in Orion are its bright stars: the bright blue Rigel, marking the hunter's foot; and, at its opposite shoulder, the red super giant Betelgeuse (Beetle Juice). Astronomers believe this massive star is a prime candidate to one day end its life in a cataclysmic explosion known as a supernova. And not just a regular nova mind you. This one wears a cape and can leap tall buildings!
It is from the remnants of such events that cosmologists believe planets and life itself evolved. They are sort of the Johnny Appleseed of the universe. Materials cooked within the core of these massive stars, which are originally comprised of predominantly hydrogen gas, as time goes on, undergo great heat and pressures which fuses atoms together and produced heavier and heavier elements, the very stuff that we're all made of.
When some of these massive stars undergo such an enigmatic end, they often leave behind what are known as Neutron stars, spinning at incredible rates of speed, detectable by the flashing beacon like signals (Pulsars) that they are known for. In the very largest stars, the results are what we call black holes. The reason for this is that the gravity produced is so strong that even the glowing light that would normally be present cannot escape. Betelgeuse is one of these candidates. There's a good chance that when it does explode, and it will, the familiar pattern we see today in Orion will be no more.
High above Orion's outstretched sword, Taurus the Bull's special jewel is the Pleiades star cluster, which attracts the eye quite naturally. It is often mistaken for the Little Dipper by novices. However, adding binoculars or a small telescope to the equation, reveals not only the famous Seven Sisters, but several dozen bright blue stars. In long exposure photographs the brightest stars of this group are seen embedded in the nebulosity of the clouds of gas and dust they were originally birthed from.
The Pleiades, or Seven Sisters is a true asterism. Catalogued as M 45 on Charles Messier's list of Deep Sky Objects, this especially enigmatic sight has enthralled observers since ancient times. Mythologically speaking, in Greek legend they represented the seven daughters of Atlas. The interesting tidbit here is that, today, most people can only see six of the original seven sisters. It is theorized that over the course of the last several millennia, one of the brighter stars of this cluster has dimmed to just beyond naked eye visibility. It's hard to prove either way, but what is much more interesting is what you'll see in a pair of binoculars or a small telescope trained on this area of sky.
Also in Taurus, you can hunt for the first of Messier's list of deep sky objects. M 1 or the Crab Nebula is quite dim. The larger the instrument you can bring to bare, the better your chances to capture this often elusive trophy. What's also interesting about the Crab Nebula, is that it is also associated with one of the first pulsars ever discovered. Both an optical and radio spectrum object, it is the remnant of what is believed to have once been a massive star that exploded into a supernova nearly a thousand years ago, recorded by Chinese astronomers in 1054.
What we see today is the debris that was left behind. Hundreds of times more massive than our own star, where once shone a sun that commanded the attention of its closest neighbors, all that is left now is nothing more than an eleven light year wide field of sinuous gas and dust clouds. Within the radio spectrum, the Crab Pulsar, early on thought to perhaps be a sentient signal from an alien race, spins like a Ferrari built lighthouse gone berserk. It produces as many as 30 pulses per second in both x ray and gamma ray wave lengths. Fortunately for us, this highly energetic beacon is over six thousand light years away.
In the other arena, facing north, Bootes, also known as The Guardian or Hunter of the Bear, is a kite shaped aggregation of stars, whose primary member, Arcturus, is the brightest star north of the celestial equator. Taking fourth place in overall brightness, this star is very large, twenty million miles across, twenty five times the size of Sol and one hundred and fifteen times brighter. This star's heat has been measured here on Earth as comparable to a single candle at five miles distance. Think about what that means. A close, warm neighbor, in galactic terms, Arcturus lies only a mere thirty seven light years away. What's even more interesting is that this star is moving quite fast in a path that will bring it past us eventually on its way towards Virgo. Passing through the plane of the galactic arm in which we reside, its velocity has been calculated to almost ninety miles per second!
There are not any real DSOs for amateur instruments within Bootes, though there are numerous double stars to attempt to split. As is true throughout the heavens, most stars belong to multiple systems mostly binaries and triples. The rogue solo star like our sun is the exception rather than the rule. A long time popular activity for both professionals and amateurs alike has been to test their toys . . . er . . . instruments on how well they are able to resolve the components of close binaries. Bootes provides one of the richest playgrounds for such activities.
Canes Venatici contains, in addition to almost a half dozen Messier targets, numerous NGC cataloged galaxies, though most of these are way beyond amateur instruments. The constellation itself lies just below the front paws of the Great Bear, Ursa Major. Known as Bootes' hunting dogs (Cor Caroli and Chara), it is a minor constellation, often overlooked. Its two major stellar components are both dim and easily disregarded in a sweep through this rich field of galaxies. It and the Big Dipper share dibs on M-51, the Whirlpool Nebula. Messier found it and cataloged it in the year 1772, noting nothing more than its nebulous and circular appearance. It wasn't until the mid eighteen hundreds that the spiral arms were detected. And in those days, before the realization that these objects were in fact other galaxies, it was postulated to be one of several evolving solar systems. This common view of the day went unchallenged until the early nineteen hundreds.
Just between and slightly above the stars Cor Caroli and Chara, you should easily be able to detect M 94, a round face on spiral galaxy. Not especially extraordinary by any means, it does, however, present itself well in a dark sky, even in small telescopes. In larger instruments you may even glimpse some of the spiral structure. Though, in this galaxy, the arms are tightly wound to the exceptionally bright central hub. M-94 is some 20 million light years away, almost ten times as far away as the Andromeda galaxy.
Near the edge of the Canes Venatici border with Bootes lies M 3, a rich globular cluster. One of the brightest clusters you can see in a small instrument or binoculars, its center is quite luminous, almost starlike with a halo of dimmer stars surrounding it. As you increase magnification, more and more of these stars can be resolved. Thousands are estimated to be possible to see in larger backyard instruments. The great 200 inch telescope at Palomar has recorded upwards of 45,000 in all. Interesting in that many of these stars are short term variables, some even doubling brightness on a scale counted in minutes.
The next Messier on the list is M 63, just below M 51 and above M 94. This galaxy resides even further away than M 94 at a whopping 35 million light years. As Messier objects go, in small telescopes this one is not especially spectacular. Even in large instruments, you'll be blessed to get any hint of its structure. It's more likely you'll just barely be able to trace out its outside circumference. This is one of those fuzzy patches where only long exposure photographs finally revealed its true nature.
Last but not least, though again, not really one of the original Messier objects, M 106 (NGC 4258) is a slightly tilted spiral that I'd consider a trophy item to see in person. In the Palomar photographs, it exhibits more spiral details in addition to its core hub. Visible in those pictures, are a few wispy arms which seem to extend out quite a ways from the main body of the galaxy, sort of like skaters on the tail end of the whip, never completely catching up to the group. All the Messiers in Canes Venatici, though, some perhaps quite dim, are attainable in amateur grade instruments. Though, as I've mentioned before, don't expect the astro-photos you're accustomed to seeing.
Try and keep warm is the best piece of advice I can offer. Convincing compatriots to share a Lawnchair experience can be difficult at this time of year. However, a pot or two of hot coffee and attendant accouterments (donuts, muffins, croissants, toaster pastries warmed on the grill, etc.) may help to increase the turn out. Between the brand new stars being hatched in the Great Nebula and the perhaps soon-to-go-boom, red giant Betelgeuse in Orion, along with the blue cluster members of the Pleiades in Taurus and the white hot Sirius of Canis Major, this assortment of heavenly inhabitants will provide hours of enjoyment. While the time you may want to devote to scanning the skies at this slightly less warm time of year is often scant, there are, as you will see, numerous special sights to help warm the heart, if not the hands and feet. I can promise you, though, that even the youngest ones get excited over this "past their bedtime" special event, while learning about the Universe and how truly magnificent it is. Dress appropriately and be ready to revel in the celestial tapestry that is pre winter Lawnchairing!
The Lawnchair Astronomer
Gerry Descoteaux is the author of “The Lawnchair Astronomer,” a Dell Trades paperback. He has been writing about astronomy for more than 25 years. He also played an integral role in the development of America Online’s pioneering distance education program known as AOL’s Online Campus and served as Professor of Astronomy there for 10 years. He can be reached at TheStarMan@thelawnchairastronomer.com.