Some Light Science Reading. The Constellations: Triangulum

As first appeared in the October 2010 edition of the Syracuse Astronomical Society newsletter The Astronomical Chronicle (PDF).

Constellation Map generated with Starry Night Pro 6.

I remember my first foray into Constellation memorization, still the first thing I recommend for anyone beginning in amateur astronomy (primarily for using these imagined creations to memorize the locations of far dimmer objects when you graduate up to binoculars or small scopes, but also simply to develop a sense of, well, the space between these creations as you jump between objects).

Orion, yeah yeah… Scorpius, O.K. obvious… The body of Sagittarius looks like a teapot, that’s not bad… Cassiopeia is the great big “W” Jonathan Winters discovered in “It’s a Mad … Mad World“… The “Dippers” are dippers… Canis Minor is composed of two stars, and they happen to be in a straight line! At least it contains a bit of animal lore and the great Procyon. That should be easy to find.

Ah! Triangulum. A famed triangle of stars. Named after the famed shape called “The Triangle,” and believed to be the last Constellation drawn out by Ptolemy as one of the original 48 Constellations of Antiquity. It bet it was supposed to be “The Great Northern Spearhead,” but Ptolemy must have been a pacifist. It is believed he committed it to papyrus at 4:50 p.m. on a Friday before the scribes began copying the first edition Monday morning.

I have to admit, this Constellation seemed like an odd member of the original series, if for no other reason than the seemingly minimal amount of work (or so I thought) that must have gone into its creation. As I hope to convey to you in the next few paragraphs, this little Constellation has stood the test of time for a few good reasons.

To begin, the heart of Triangulum dates back all the way to the Babylonians (which means it likely also dates back further into pre-recorded history) who, with the inclusion of what we now know as γ-Andromeda, called this Constellation MUL.APIN, or “The Plough.” With this simple extension added in red in the image above, I hope the resemblance is now obvious. To my technologically-biased mind, the nondescript triangle of the modern sky instantaneously becomes the (seemingly) everlasting testament to the power of agriculture and the shining reminder to all of the simple tool responsible for the creation of a commodity we know today as “surplus.” I don’t think that’s going too overboard in the description.

You are here.

We have these “organic farming” discussions where people ask you “Where do you think your food comes from?” It has been quite a recent phenomenon in the long history of this little sphere Carl Sagan referred to as a “Pale Blue Dot” (that’s you at right) that the members of a society have been relieved of the strain of producing for themselves by technology that improves efficiency and, more importantly, vastly increases quantity. If I take the comparison to the extreme, the Constellations that represented tools or deities have been replaced in many societies by the gigantic billboards that celebrate the financial well-being of companies continuing their crusade to relieve you of your currency, an economic reality impossible in a society where everyone’s working entirely to maintain a base subsistence level. The world remains in transition towards a time when all are at the same technological level as the First World countries (and it is only a matter of time), meaning something as simple to many of you reading this as an animal-driven plough remains a vital key to survival in other parts of the world.

I vote we re-designate the “Summer Triangle” as the “Summer Plough!”

While it may have been a signal for a Late-Summer party at the very beginning of some harvest, the Babylonians used the presence of their Triangulum to mark the “Way of Enlil,” the apparent path of the Sun after the Summer Solstice. In a society that used the Heavens as their Calendar, this simple Constellation took on a wholly more significant meaning.

Thanks to wikipedia, I know that a more recent attribution (to only the Triangle, not the Plough) of this Constellation is to the goddess Ceres, who successfully convinced the god Jupiter to add the island of Sicily (at left, the football that the boot of Italy appears to be kicking towards the U.S.) to the Night Sky (perhaps a preferred way to leave your mark in history, esp. given the alternative taken by Atlantis).

Sicily, featuring an active Mount Etna (Image by Jacques Descloitres, NASA MODIS Land Rapid Response Team).

Given this most interesting history, is there anything to actually do with a pair of eyes or an eyepiece in this part of the sky? I’m pleased to report that this part of the sky is actually quite busy (the Star Map at this beginning of this article is about as busy as one can get without looking at Sagittarius), with Triangulum serving as a useful anchor for finding a number of objects in our Eastern sky this month.

M33, the Triangulum Galaxy. Photo by Hunter Wilson.

As it happens, one of the precious few naked eye galaxies (provided ideal viewing conditions) in the Northern Sky lies just to the South (to the right as you’re looking at it) of α-Tri. M33 (at right), appropriately named the “Triangulum Galaxy,” is a member of the Local Group of galaxies (the most famous member being our Milky Way, the second most famous being the Andromeda Galaxy) and, at 2.9 million light years away, lies (by some estimates) 700,000 light years farther from us than the Andromeda Galaxy (M31) AND, according to measurements using the Very Long Baseline Array, is moving at 190 km/second relative to us and towards M31 (the demolition derby will not be pleasant for M33, given it contains only 4% of the stars of M31 (how many mopeds are there in a semi-rig?). It is still under debate as to whether or not M33 is a companion galaxy to the more massive M31 (they do share proximity), but it certainly stands on its own as a spectacle in a good telescope on a dark night. This first recorded observation (it all comes down to paper) is attributed to Giovanni Battista Hodierna around 1650 (above at left), the most famous recorded observation (it all comes down to publication) can be given to Charles Messier (above at right) on August 25-26, 1764 (now that’s bookkeeping!).

Giovanni Battista Hodierna (left) and Charles Messier (right).

All of the other objects in the boundaries of Triangulum are dim (10>th order or dimmer), making your time spent with moderate optics in this area short compared to the time you’d likely spend just on M31 alone. As a good practice for the next Messier Marathon, you can use M33 (*1) and M31 (*2) to mark the Southern side of a rectangle composed of M33, M31, M34 (*3) and M76 (*4, these last two are right on the Perseus-Andromeda border). As M33 will give you M32 and M101, that’s a quick-six to check off as you plough your way through the list of 110.

Comet Hartley 2 and NGC 457 (the E.T. Cluster). Photo by SAS member Stu Forster.

AND, as long as were in this neck of the woods (and the tree line in this part of the sky at Darling Hill is now just becoming more bearable to the impatient observer with the falling of leaves), we can use the Babylonian form of Triangulum to quickly point our way to M76, then slowly walk the Telrad to the North (left) until we reach the Southern Double of the famed Double-Double, which then puts into view both members of the Perseus Double-Double Cluster (NGC 884 and NGC 869) and Comet Hartley 2, which is working its way through our neighborhood. Our own Stu Forster managed to capture Hartley (green glow at left) as it passed through the local neighborhood of NGC 457, more commonly known as the Owl or E.T. Cluster (yes. tha E.T., the two bright eyes work for both).

Clear skies, Damian

Some Light Science Reading. The Constellations: Pegasus

As first appeared in the September 2010 edition of the Syracuse Astronomical Society newsletter The Astronomical Chronicle (PDF).

Constellation Map generated with Starry Night Pro 6.

The Constellation this month is one light on interesting binocular and telescope objects but heavy in mythology and Naked Eye observing. To the Babylonians, the stars in this region also (or first) took on the shape of a horse known as MUL.ANSHE.KUR.RA. To the Greeks, sometimes a horse is not (just) a horse (of course, of course). The Greek mythology surrounding the winged horse Pegasus is, to say the least, involved and undecided. There are several pages discussing the mythology of Pegasus, which I refer you to in the interest of local brevity.

The torso of Pegasus is composed of a “Great Square” of stars that is very easy to see and is very often pointed out to visitors at this time of year at Darling Hill. This asterism (simply any grouping of stars that are not officially constellations) lies to the right (or south) of the Andromeda Galaxy (M31), one of the great views in the Autumn skies. As the scope is pointed in this direction anyway for a good block of time during Public Viewing sessions, the walk through some of the nearby Constellations (Cassiopeia, Perseus, Andromeda, Pegasus, Cepheus) reads like a Cliff Notes version of both Clash Of The Titans movies (unless John McMahon is running the presentation, in which case you’re guaranteed a much better show). In the modern definition of the Constellations, the south-most (or upper left corner) star belongs instead to the Constellation Andromeda (but anyone staring at this part of the sky would be hard pressed to be struck more by the “Great Triangle” of Pegasus than the “Great Square” of Pegasus).

There are only two significant (and visually accessible) objects within Pegasus (the Constellation, that is) for the binocular and telescope viewer at Darling Hill. The first of these is the appropriately named Pegasus Cluster (M15), an ancient globular cluster clocked at 13.2 billion years of age. This cluster appears as a smaller version of M13 in Hercules, as captured by our own Stu Forster in the September 2008 Member Gallery and shown below. The second object is a far more difficult find, the very unique spiral galaxy NGC 7742 (below). The presence of a prominent ring in this galaxy (or, more specifically, the absence of pronounced spiraling from the center of the galaxy out to the edges) is a point of unexplained inquiry in modern astrophysics.

M15, photo taken by SAS member Stu Forster.
NGC 7742, image from the Hubble Heritage Team (AURA/STScI/NASA/ESA).

The most curious content on the wikipedia page for Pegasus involves the nontrivial amount of discussion about the reinterpretation of its connectivity by one H. A. Rey in, specifically, his book The Stars — A New Way To See Them. Rey’s goal in this book is to redefine connectivity of some of the Constellations to make them a bit easier to see as the mythical beasts they are known for. For Pegasus (see below), Rey has eliminated any mention of Sirrah (or Alpheratz, as it’s known within Andromeda), using the Great Square as a Great Triangle that marks the above-the-shoulder wings over the trapezoid torso (with the rest of the limbs along the southern edge of the Constellation). Upon inspection, his reinterpretation looked more to me like one of the drawings of The Man In The Yellow Hat who, along with Curious George, is perhaps the more famous of the illustrated characters created by H. A. Rey.

A new view of an old constellation, or The Batman In The Yellow Hat.

I’ll admit I’m mildly ambivalent about the redefinition of Constellation connectivity. On the one hand, the Constellations are one of the oldest memes in human history among all societies (extant or extinct) and, to that end, connectivity has meaning as a way of marking out specific arrangements that have largely stood the test of time. The consistency of connectivity also provides a way to reduce the memorization fatigue that comes from having to see groups of stars in slightly different ways (clearly, one arrangement is easier to know and explain than several). This is of further significance when one uses Constellations as a specific guide to locating Messier (or other) objects. If I tell you that “M15 is on an almost straight line about 1/2 the distance of the two stars that make up the snout,” you really have to trust that we’re seeing the same horse!

On the other hand, there are many amateur astronomers who use Constellations largely as tools for finding smaller objects (with or without a knowledge of their history) and, as we are a species that excels at pattern recognition (how many flying faces and hippopotami can you see on a partly cloudy afternoon?), anything that makes life easier for you the observer (especially on cold nights when observing time is at a premium) should be added to your observing arsenal. H. A. Rey’s interpretation of Pegasus connectivity might cloud just how pronounced the Great Square is (so you have to then present this Constellation with an addendum!), but it certainly does look more like a complete flying horse than the common artistic rendering of only the front half (clearly the side you’d want to have over you anyway given both choices).

Any way you look at it, it’s still safe to assume that the winged horse must have been the most efficient way to travel in the ancient world. It certainly speeds up a good plot.

Clear skies, Damian

Some Light Science Reading. The Constellations: Taurus

As first appeared in the November 2009 edition of the Syracuse Astronomical Society newsletter The Astronomical Chronicle (PDF).

Constellation Map generated with Starry Night Pro 6.

This month’s constellation is one of the best in the Night Sky for combining ancient tradition, mythology, modern astronomy, world history, stellar eye candy, and even modern engineering into one reasonably small bordered pen of celestial real estate. The early evening sight of the constellation Taurus the Bull in the November southeast sky at Darling Hill might appear to CNY viewers as a snow divining rod pointing to the western Great Lakes in anticipation of winter and the upcoming lake-effect snow. Taurus is a distinctive constellation and very easy to identify once its central asterism is identified. The brightest star in the constellation is almost equidistant from the easily identified Pleiades and the shoulder of the constellation Orion, the celestial hunter Taurus is running from as the sky appears to move (or, from the most commonly drawn orientation, right towards him!). While Taurus is mildly sparse in quantity when it comes to dark sky objects, it more than makes up for it in quality, hosting two of the most significant stellar sights in the Night Sky.

Like its neighbor Orion, Taurus the Bull is a very, very old constellation and has been recognized as a bull for the duration of its existence in Middle Eastern and European traditions. Earliest records of any kind place the birth of Taurus in the Copper (Chalcolithic) Age (4500 – 3500 B.C.E.), although some records support its existence even earlier. The presence of a bull and what appears to be a Pleiades-like star formation exists on a wall in the Lascaux Caves of France (see right). Although the interpretation of the Constellation set is controversial, this arrangement may date back as far as 16,500 years. Personally, I find even the thought of that kind of continuity between what we might see in the winter skies and what our ancestors also saw at night both comforting and humbling. Many of the same stand-out patterns we know today no doubt stood out immediately to them as the brightest objects in the sky marked out regular places as the Sun set, and the great distance we’ve traveled in history might be barely perceptible to an ancient astronomer going simply by the positions of stars.

Lascaux Cave bull and star pattern. From the Institute for Interdisciplinary Studies and spacetoday.org.

We begin the tour by aiming our sights at the bright eye of the bull, the star Aldebaran. This orange giant is 44 times the diameter of our own Sun and has already used its hydrogen fuel, leaving this fusion engine to now graze on a steady diet of helium. Its name is derived from the Arabic for “the follower,” often reported as in reference to its position below the Pleiades (so “following” this open cluster as we progress into winter). The other stars in Taurus are easy to see in darker skies but not otherwise noteworthy for their brightness at either naked-eye or binocular viewing magnification. Several of the bright stars closest to Aldebaran make up an asterism that a new observer might confuse with the complete constellation. The V-shaped Hyades (center of the image below and shown at right with white border) are composed of five stars, with Aldebaran the brightest tip. I’ll admit that the first time I marked out the space for Taurus, I confused this asterism (and lambda-Tau to the west) with the entire object before double-checking the size. No bull. The Hyades star closest to Aldebaran, theta-Tau, is actually a pair of pairs, although they only appear as a single bright pair in binoculars and telescopes.

The Hyades (white) and Pleiades (red). From Lynn Laux, nightskyinfo.com.

Caught within the bull pen is the Pleiades (M45, shown labeled below from a Hubble image). This Tiny Dipper is visible year-round during the daytime in parking lots and slow-moving traffic everywhere (as the object embedded within the emblem on every Subaru, the Japanese name for this asterism) and is one of the treats of winter viewing in CNY (unless VERY early morning viewing is your game or you’ve been trying to see Mars in the late Summer skies, in which case you’ve been enjoying the pre-dawn sight of M45 since August). The amount of information available on the Pleiades online and as part of space research could easily (and very likely has) fill an entire book. While the seven bright stars are identified from Greek mythology as the Seven Sisters (Sterope, Merope, Electra, Maia, Taygete, Celaeno, and Alcyone), the counting aid that comes from a pair of binoculars easily reveals nine stars. The two stars that make up the handle of this tiny dipper are the proud parents Atlas and Pleione, placed to the east of the dipper to protect their daughters from either Taurus (for being a bull) or Orion (for being a male). Given the long history of this asterism, it is perhaps not surprising that the parents decided not to stop at seven. In fact, there are over 1,000 distinct stars in the Pleiades that have been revealed as part of multiple high-resolution studies. This density of stars makes the Pleiades a unique open cluster, as there is a wealth of stars and patterns visible at virtually any magnification, from small binoculars to the largest ground-based telescopes. For my first proper viewing session, I spent one full hour simply looking at this cluster through my Nikon 12×50’s, amazed at just how little we really see of the Night Sky using the 1×7 binoculars built into our heads (and, perhaps, corrected by horn-rimmed glasses).

The Pleiades in detail. Image from hubblesite.org and wikipedia.org

On the opposite side of Taurus and caught between the horns is the first of the categorized Messier objects, the Crab Nebula. M1 to its friends, this nebula is a supernova remnant with a remarkable history. As documented in both Arab and Chinese texts (Europe was just coming out its, er, Dark Ages at the time), this supernova was so bright on July 4, 1054 that it was visible during daylight hours (and, as you can guess by the date, visible without any magnification). The supernova remnant we know today as the Crab Nebula was discovered (and correlated to the original supernova) first by John Bevis in 1731, then by Charles Messier in 1758 while, as it happens, observing a comet (that Messier is known best for his catalogue of objects that were NOT comets instead of the comets he worked so diligently to discover is one of the great fun ironies of astronomy). The NASA images of the Crab Nebula reveal a dense sponge-like structure full of filaments of all sizes. The image above shows a remarkable sight – the full cycle of the pulsar at the heart of the crab that continues to magnetically drive the expansion of the nebula (in the series of frames, the pulsar lies below and to the right of a constant-brightness star).

The Crab Nebula pulsar. Image from www.strw.leidenuniv.nl

Stepping forward several hundred years, Taurus also marks the present locations of Pioneer 10 and COSMOS 1844. Pioneer 10 is currently speeding in the direction of Aldebaran, having been successfully steered through the asteroid belt to make a series of images of Jupiter. At its current velocity, this trip to Aldebaran’s current location would take 2 million years, about the same amount of time it might take most of the world to decipher the meaning of the emblematic plaque attached to its exterior (below). Perhaps someday we’ll have to explain to the aliens how a civilization that could launch a complicated probe into space couldn’t see the multitude of planets in their own Solar System, then perhaps have to explain what happened to Pluto hat it no longer appears in our Solar System images. COSMOS 1844 is one of over 2440 satellites launched by the Soviet Union (and now Russia) since the first of the COSMOS series in 1962. At mag. 5, this satellite makes for a fun artificial viewing target (with a good map in hand).

The Pioneer 10 plaque. From wikipedia.org.

The final sights for telescope viewers include four NGC objects. NGC 1746, 1647, and 1807 are open clusters with magnitudes between 6 and 7. NGC 1514 (below) is a mag 10 planetary nebula just at the far edge of the Taurus border that should be increasingly good viewing as Taurus works its way towards our zenith (1514 will be the closest it will get to our zenith by midnight, a perfect last-good-look before Darling Hill completely freezes over).

NGC 1514. From Martin Germano, seds.org)

Phenomenal viewing at a reasonably safe distance. Just be mindful not to wave your red flashlights at Aldebaran!

www.syracuse-astro.org
http://en.wikipedia.org/wiki/Taurus_%28constellation%29
http://en.wikipedia.org/wiki/Divining_rod
http://en.wikipedia.org/wiki/Great_Lakes
http://en.wikipedia.org/wiki/Lake_effect_snow
http://en.wikipedia.org/wiki/Orion_%28constellation%29
http://en.wikipedia.org/wiki/Chalcolithic
http://en.wikipedia.org/wiki/Lascaux_Caves
www.spacetoday.org/SolSys/Earth/OldStarCharts.html
http://en.wikipedia.org/wiki/Aldebaran
http://en.wikipedia.org/wiki/Hyades_%28star_cluster%29
http://www.nightskyinfo.com/archive/hyades/
http://en.wikipedia.org/wiki/Pleiades_%28star_cluster%29
http://www.subaru.com/
http://en.wikipedia.org/wiki/Mars
http://en.wikipedia.org/wiki/Sterope_(Pleiad)
http://en.wikipedia.org/wiki/Merope
http://en.wikipedia.org/wiki/Electra_(Pleiad)
http://en.wikipedia.org/wiki/Maia_(mythology)
http://en.wikipedia.org/wiki/Taygete
http://en.wikipedia.org/wiki/Celaeno
http://en.wikipedia.org/wiki/Alcyone_(star)
http://en.wikipedia.org/wiki/Atlas_(mythology)
http://en.wikipedia.org/wiki/Pleione_(mythology)
http://en.wikipedia.org/wiki/Crab_Nebula
http://en.wikipedia.org/wiki/Dark_Ages
http://en.wikipedia.org/wiki/John_Bevis
http://en.wikipedia.org/wiki/Charles_Messier
http://www.nasa.gov
http://www.strw.leidenuniv.nl/~oberg/Pulsars/external.html
http://en.wikipedia.org/wiki/Pioneer_10
http://en.wikipedia.org/wiki/Jupiter
http://en.wikipedia.org/wiki/Pluto
http://en.wikipedia.org/wiki/Cosmos_%28satellite%29
http://en.wikipedia.org/wiki/Pioneer_plaque
http://server1.wikisky.org/starview?object_type=4&object_id=241&object_name=NGC+1746&locale=EN
http://server1.wikisky.org/starview?object_type=4&object_id=211&object_name=NGC+1647&locale=EN
http://server1.wikisky.org/starview?object_type=4&object_id=279&object_name=NGC+1807&locale=EN
http://seds.org/~spider/ngc/ngc.cgi?NGC1514