Some Light Science Reading. The Constellations: Draco

As first appeared in the May 2012 edition of the Syracuse Astronomical Society newsletter The Astronomical Chronicle.


Image generated with Starry Night Pro 6.

We return to our circumpolar constellation discussion begun with the Jan/Feb/March 2012 issue (our first "quarterly" report) by scaling up the Northern Horizon towards Draco the Dragon.

Draco, like all reptiles, is a bit on the dim side. Most of its constituent stars are in the 3 to 4.5 Magnitude range, making it an easy target in dark skies but a bit of a hunt near larger cities. If you've never looked for it before, it rivals Ursa Minor (the Little Dipper) in terms of "meh" apparent brightness in the sky (so it is far less pronounced than the Big Dipper or Cassiopeia, the two most prominent Constellations in this part of the sky).

Your best bet for identifying the stars in Draco may be to start right at the head and work your way down (and around, then over, then up, then way over the other way). One of my recent discoveries is that the head of Draco is, itself, a noted asterism (or noteworthy arrangement of stars that are not of the proper 88 Constellations) referred to as "The Lozenge" ("1" in the image above). I had been subconsciously thinking of Monty Python references to throw into this article and realized that saying "The Lozenge" several in a low John Cleese voice a la "The Larch" just about does it. The head of Draco is made from the brightest stars in the Constellation and does make for a reasonably easy target, as it sits between the two bright stars of the Little Dipper's bowl ("2" In the image at right) and Vega ("3"), the ridiculously bright star making its triumphant return to Spring skies (if you're at Darling Hill near sunset, you will see Vega as one of the first stars to appear above the Eastern Horizon well before it gets really dark). For those of you familiar with the Keystone (another famed asterism) that makes up the torso of Hercules ("4" in the image above), simply drive your eyes to the left-ish during the early night.

The historical origins of Draco as a lizard of any kind are localized to the Mediterranean, and these origins go back far enough that Draco is one of the Almagest's Original 48. The Greeks, and so the Romans, saw Draco as a Dragon (or, at least, lizard) of generally ill repute. Draco was seen by the Greeks as a guard of Hesperides' golden apples and/or a guard (or target, depending on how you read the sentence) of Jason's mythical golden fleece. The Romans saw Draco as the remains of the dragon killed by their goddess Minerva. It is perhaps fitting that, if you imagine Ursa Minor (the Little Dipper) as an ax on a questionably straight handle, then Draco is precariously on the celestial chopping block preparing to be cleft in twain.

The body of Draco is a healthy mix of single and double stars. In the boring single star category are Giausar, Thuban, and Nodus I. The double star list includes Edasich, Aldhibain, Altais, Rastaban ("eh mahn!"), Eltanin, and Grumium.

Thuban is one star in Draco to spend a bit of time on. In fact, it's one to spend several thousand years on. As late as 2700 B.C.E., Thuban held the place of Polaris as our North Star. The Earth may seem reasonably unchanging with respect to the seemingly unchanging arrangement of stars of our 100-year-ish lifetimes, but on the geological or cosmological timescales our Earth is as dynamic and fast-moving as that famed clay dreidel. The 26,000-year cycle we know as the precession of the equinoxes (shown above) is one of those processes that requires nearly the entire history of what we know as civilization to mark significant timespans for, but it is reported in several places that Thuban was of significance to the Egyptians in their building of the pyramids over 5 millennia ago (I would be happy to report that Thuban was the North Star that the main shaft of the great pyramid of Cheops was aligned to, but I've found conflicting reports online from otherwise reputable locations, so will simply report that the Egyptians very likely knew that this star appeared to move far less over the course of the night than any other and, therefore, held it with great regard).

For those observing at Darling Hill or anywhere south of Syracuse, Draco is a tough reptile to sustain one's astronomical appetite on. At least two comets are currently passing through Draco at the moment. One, LINEAR (C/2011 F1), is just off the Spindle Galaxy M102 (we'll come back to that) and, at 3 a.u. and closing, may improve beyond its apparent magnitude of 12.5. Draco also hosts Garradd (C/2008 P1) far beyond its tail star. At an apparent magnitude of 21.30, you have absolutely NO chance of seeing this comet from Darling Hill.

Draco is regrettably light on deep sky objects as well. The local color (at about 3400 light year) is provided by NGC 6543, known as the Cat's Eye Nebula (above). This is regarded as one of the most structurally complex nebulae in the Night Sky, although this complexity is only revealed through astrophotographic studies. NGC 5866 (below), also known as the Spindle Galaxy (which is very likely Messier 102, although some debate exists), is one of the great photographic sights in astronomy to my eyes. This edge-on galaxy view produces amazing density of material and spindly, fibrous clouds of dust and stars along the plane of the galaxy and a bright glow of stars all around this dense, dark line.

Now, the long curving body of Draco and its positions near the North Star does afford it one benefit in the Northern Horizon. Satellites! There are many bright (brighter than magnitude 4.0) satellites that follow paths over the Earth's poles, meaning those Constellations near the North and South poles are constantly getting pierced by manmade weather, communications, and "other" satellites. Simply letting my copy of Starry Night Pro go at high-speed with Draco at the center reveals over a dozen of these satellites over the course of just a few hours.

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