Some Light Science Reading. The Constellations: Cetus

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.

There is a region of the Night Sky that is dominated by aquatic creatures. Alternately, if we consider empty space as its own kind of ocean, there are regions where the stars of the Aquatic Constellations appear to undulate at geologic time scales, making the current arrangement of stars effectively motionless to our eyes and those of many generations to come.

Within this Water Region are the Constellations (as listed at wikipedia) Aquarius, Capricornus, Cetus, Delphinus, Eridanus, Hydra, Pisces, and Piscis Austrinus. If we think in terms of seasonal change, this does seem like an oddity of planning. Who would place the Aquatic Constellations in the Night Sky during the late fall and winter, when the temperature in some parts of the Northern Hemisphere (such as at Darling Hill Observatory) might as well be that of interstellar space? Where are the polar bear and penguin Constellations?

Constellation Map generated with Starry Night Pro 6.

The answer to this has less to do with the apparent location of these Constellations in our Night Sky and more to do with the position of the Sun during our daytime sky roughly six months later (the Sun IN Pisces, for instance). When the Sun is in this region of the sky from our terrestrial perspective, the Northern Hemisphere is well into Spring, the time of the rainy season in our and ancient cultures. The image above shows the position of the Sun at noon on April 1, 2011. No joke. If our blue sky were to disappear, we'd have a few seconds to enjoy the daytime Constellations (before we passed out, were cooked by radiation, or froze to death, depending on where the atmosphere went. Fun factoid – Mercury, with no atmosphere to speak of, provides 24-hour Constellation observing!).

This brings us to Cetus, formerly known as a sea monster (indirect evidence for the lack of submarines in ancient Greece?), now increasingly considered to be a whale (perhaps equally terrifying to a small boat far from land in antiquity). Like some misidentified sea monster seen from a dry beach by a hydrophobic observer, Cetus provides a small amount of clear identification and several subtle treats for Earth-locked amateur astronomers that leave quite a bit to the imagination.

Constellation Map generated with Starry Night Pro 6.

One of the patient treats in Cetus is the variable multiple star Mira (Omicron Ceti). As our Observatory Director Ray Dague pointed out at our last Public Viewing session, this star takes its own 331.65 day journey from a 10.1 magnitude star to a 2.0 magnitude star. That is a phenomenal change! It is current at 6.5 magnitude and found in the neck of the beast (above).

M77 image by Hunter Wilson.

As for Messier Objects, those objects one can definitely say they saw on first pass with even moderately-sized binoculars, Cetus is accompanied by only M77, a distant (47 million light years away) barred spiral galaxy (at left, photo by Hunter Wilson). While one distant galaxy is anchored in this part of the sky, this small region is host to tens-of-thousands of invisible objects swimming around our Sun. Cetus is a border Constellation to the Zodiac, those 12 Constellations that mark the path of the Sun and planets from our observing post on Earth. By the way the borders are drawn, Cetus does play host very occasionally to planets and, notably, the objects of the Asteroid Belt. Cetus had the distinction of being the host to 4 Vesta (shown below, photo from the Hubble Space Telescope), the 2nd largest object identified in the Asteroid Belt, during its discovery on 29 March 1807 by Heinrich Wilhelm Olbers.

4 Vesta (Images taken 2007 May 14 and 16). From hubblesite.org.

And then there's stuff we can only imagine seeing without the most powerful scopes in the known universe. Cetus is the host to JKCS 041 (shown below, also in the neck as marked in the opening image. Must be a hungry monster), the current holder of the title as most distant galaxy cluster yet discovered, residing at a boggling distance of 10.2 billion light years from us. Wikipedia hosts a short little movie about this distant cluster HERE.

JKCS 041 (22 Oct 2009) from NASA/CXC/INAF/S.Andreon et al Optical: DSS; ESO/VLT.

Clear skies, Damian

P.S. It has taken all my concentration to not refer to Cetus as a Whale of a Constellation.

Some Light Science Reading. The Constellations: Pisces

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

Constellation Map generated with Starry Night Pro 6.

Those who've ever been told that "there are more fish in the sea…" should be relieved that we only cast our visual nets to the heavens for stars and galaxies, as this most important of animals throughout history is only represented in the Northern Hemisphere by one pair of gilled swimmers tied at the tails.

The identification of one-half of this constellation as a fish (its other half had originally been a dove) dates back to at least Babylonian times, when a second great Western civilization prospered in the valley of the Tigris and Euphrates rivers to the West of Egypt, home of the first great Western civilization at the Nile Delta. The two civilizations from which most of the astrology (and mythology) that turned into early astronomy was established were founded by key water sources, providing the means for irrigation, transportation, and stable food supplies in the form of fishing, the three key needs of a society that allow for growth and the ability of the few to support the many (as James Burke has considered in Connections and The Day The Universe Changed, the ability of people to NOT need to provide subsistence level support for a society is what promotes scientific growth, cultural evolution, and whatever other types of activities most of us attend to everyday while some small fraction of the U.S. harvests or raises the food that the rest of us consume with hasty abandon). The Greeks eventually solidified the tied-fish representation of Pisces, representing Aphrodite and Eros, tied to one another during their escape from the god Typhon (You can guess how he rolled… In this case, the two were tied so as not to loose one another in the river Euphrates).

This constellation is reasonably large in visual real estate compared to other members of the Zodiac, but is occupied by fairly unremarkable stars, making Pisces one of the less prominent objects in the sky (it is possible you know the location of Pisces by looking below the more pronounced square of Pegasus). Pisces is made pronounced currently by its having caught Jupiter and Uranus at its Southern side, with Jupiter now making its way through Pisces (with a small fraction of time in Cetus) on its way into Aries this time next year. Most all observers will have Jupiter in their scopes at some point this Summer and Fall, giving them a chance to take in a second of the large gas giants in our Solar system as well as one solitary Messier Object within the Pisces boundary while having to move their scopes only slightly.

The only Messier Object within the Pisces boundary is M74, a less-pronounced cousin of the also face-on Whirlpool Galaxy (M51). In Hubble images (below), the bright cloudiness almost shrouds the spiral quality of the galaxy. An infrared image taken with the Spitzer Space Telescope (below) reveals a pronounced web-like quality to this galaxy, as well as some greater definition in the M74 spiral shape.

M74, image from NASA, ESA and the GMOS Commissioning Team.
Infrared image of M74 taken by the Spitzer Space Telescope.

For those attempting to check two planets of their list while memorizing the shape of Pisces, the image below provides you a reasonable cheat-sheet for how to hop from the very prominent (magnitude of -3) Jupiter ("1") to the markedly less prominent (magnitude 5.75) Uranus ("3"). You'll note in the image that the four famous Galilean Satellites of Jupiter (Ganymede, Io, Callisto, and Europa) are virtually on top of one another at this "magnification," giving you an idea of how far the motion will be to find Uranus in your eyepiece. From among the many (invisible) other moons of Jupiter (all of the labels in this image are just a fraction of the total count to date), you'll note a 6th magnitude star at position "2", the brightest other object in the sky in this area. A slow, cautious scope motion to your south-east (and low magnification to start) will help you capture a view of this small blue-ish globe, a fitting color to search for within this aquatic constellation.

Finding Uranus starting at Jupiter. Map generated with Starry Night Pro 6.

Clear skies, Damian

Some Light Science Reading. The Constellations: Aquarius

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

Constellation Map generated with Starry Night Pro 6.

Of all of the Constellations that have taken human forms through history, Aquarius the Water Bearer may have the most varied professional background. His career peaked early in human history, with the Babylonians identifying Aquarius as GU.LA, their identifier for the god Ea, Ea derived from the Sumerian god Enki. To put that into perspective, the stars of Aquarius have been recognized as a Constellation since, at the very least, 1200 B.C. (the dates of the oldest known Babylonian star catalogues. As these catalogues borrow heavily from Sumerian mythology, we can only assume his actual origins step significantly further back, although records are difficult to come by). His demotion to water bearer comes with his adoption by the Greeks and his inclusion into their mythology, with his aquatic status in Greek mythology traveling, albeit likely by land routes, as far East as India. Then, like a leisure suit-clad Pat Boone on his pre-heavy metal reinvention, Aquarius found considerable recent fame as a disco star. When one starts at the top, it would seem that careers, like water, run downhill (although he may not yet be ready for the Chinese Constellation Fenmu, the tomb composed of the upper-left set of his stars). Its importance to several cultures throughout history is of little surprise, as this collection of stars, like the other 11 members of the Zodiac, lies along the ecliptic, the perceived path of the Sun over the course of the year.

NGC 7293. From hubblesite.org

NGC 7009. From hubblesite.org

As of this writing, Aquarius and the waters spilling from his flask separate the planets Jupiter and Neptune (with Jupiter prominent in our night time sky in Capricornus) from Uranus, which lies just on the inside edge of the boundaries of Pisces. Within his borders lie several interesting objects for binocular and telescope viewers alike, including two Messier globular clusters (M2, M72), one Messier open cluster (M73), and two prominent NGC objects. Had the Helix Nebula (NGC 7293, left) been discovered in far more recent times instead of its 1824 origins, its name night instead be the Eye Nebula, a description more in line with the many Hubble and ground-based images generated in the past few years. The full-size image (HERE) is a sight to behold. The Saturn Nebula (right, NGC 7009) makes a nearly straight line with M72 and M73, making this a very dense patch of outstanding objects. Herschel documented its discovery in late 1782, but it took the Hubble telescope to again add to its fame as a beautiful and complex object.

While the star connection provided by Starry Night Pro (shown above) is as legit as any other, I found the connection pattern shown at right (from wikipedia) to perhaps be a bit easier to visualize as a human with a large jug, although this view is decidedly of a clumsier water bearer spilling the jug contents ahead of him (below). Someone should tell this version of him to not quit his day job.

Constellation Map generated with Starry Night Pro 6.

www.syracuse-astro.org
en.wikipedia.org/wiki/Aquarius_(constellation)
en.wikipedia.org/wiki/Babylon
en.wikipedia.org/wiki/Ea_(Babylonian_god)
en.wikipedia.org/wiki/Sumer
en.wikipedia.org/wiki/Constellation
en.wikipedia.org/wiki/Pat_Boone
en.wikipedia.org/wiki/Age_of_Aquarius
www.ianridpath.com/startales/aquarius.htm
en.wikipedia.org/wiki/Zodiac
en.wikipedia.org/wiki/Ecliptic
en.wikipedia.org/wiki/Sun
en.wikipedia.org/wiki/Jupiter
en.wikipedia.org/wiki/Neptune
en.wikipedia.org/wiki/Capricornus
en.wikipedia.org/wiki/Uranus
en.wikipedia.org/wiki/Pisces_(constellation)
en.wikipedia.org/wiki/Messier_2
en.wikipedia.org/wiki/Messier_72
en.wikipedia.org/wiki/Messier_73
en.wikipedia.org/wiki/Helix_nebula
hubblesite.org
upload.wikimedia.org/wikipedia/commons/b/b1/NGC7293_%282004%29.jpg
en.wikipedia.org/wiki/Saturn_Nebula
en.wikipedia.org/wiki/William_Herschel
en.wikipedia.org/wiki/Main_Page