Messier 6 – The Butterfly Cluster

Welcome back to Messier Monday! We continue our tribute to our dear friend, Tammy Plotner, by looking at Messier 6, otherwise known as NGC 6405 and the Butterfly Cluster. Enjoy!

In the late 18th century, Charles Messier was busy hunting for comets in the night sky, and noticed several “nebulous” objects. After initially mistaking them for the comets he was seeking, he began to compile a list of these objects so other astronomers would not make the same mistake. Known as the Messier Catalog, this list consists of 100 objects, consisting of distant galaxies, nebulae, and star clusters.

This Catalog would go on to become a major milestone in the history of astronomy, as well as the study of Deep Sky Objects. Among the many famous objects in this catalog is M6 (aka. NGC 6405), an open cluster of stars in the constellation of Scorpius. Because of its vague resemblance to a butterfly, it is known as the Butterfly Cluster.

Continue reading “Messier 6 – The Butterfly Cluster”

The Aquarius Constellation

Welcome back to Constellation Friday! Today, we will be dealing with one of the best-known constellations, that “watery” asterism and section of the sky known as Aquarius. Cue the soundtrack from Hair!

In the 2nd century CE, Greek-Egyptian astronomer Claudius Ptolemaeus (aka. Ptolemy) compiled a list of all the-then known constellations. This work (known as the Almagest) would remain the definitive guide to astronomy and astrology for over a thousand years. Among the 48 constellations listed in this book was Aquarius, a constellation of the zodiac that stretches from the celestial equator to the southern hemisphere.

Also known as the “Water Carrier”, Aquarius is bordered by Pegasus, Equuleus and Delphinus at the north, Aquila to the west, Capricornus to the south-west, Piscis Austrinus and Sculptor to the south, Cetus to the east and Pisces to the north-east. Today, it is one of the 88 constellations recognized by the International Astronomical Union (IAU), and is perhaps the most referenced and recognized of all the constellation.

Continue reading “The Aquarius Constellation”

The Apus Constellation

Welcome back to Constellation Friday! Today, we will be dealing with the beautiful bird-of-paradise itself, the Apus constellation!

The Southern Hemisphere is replete with beautiful stars and constellations, enough to keep a stargazing enthusiast busy for a lifetime. For countless centuries, the indigenous peoples of South America, South Africa, Australia and the South Pacific have looked up at these stars and drawn inspiration. However, to European astronomers, they remained uncharted and unknown until the 16th century.

It was during this time that Flemish astronomer Petrus Plancius designated twelve constellations, using asterisms found in the southern skies. One such constellation was Apus, a faint constellation in the southern sky that is named for the bird-of-paradise – a beautiful bird that is indigenous to the South Pacific. Today, it is one of the 88 constellations defined by the International Astronomic Union (IAU).

Name and Meaning:

The name Apus is derived from Greek word apous, which literally means “no feet”. The name applies to a species of bird that is indigenous to Indonesia, Papua New Guinea, and Eastern Australia (which was believed at one time to have no feet). Its original name on Plancius’ charts was “Apis Indica” – the Latin term for “Indian Bee” (presumably an error for “avis”, which means bird).

Because of this error, the bordering constellation of Musca was later separated and renamed. The neighboring constellations to Apus are Ara, Chamaeleon, Circinus, Musca, Octans, Pavo, and Triangulum Australe.

The Constellation Apus. Credit: iau.org
The Constellation Apus. Credit: iau.org

History of Observation:

This faint southern constellation of Apus was one of the original twelve created by Plancius, based on observations provided by Pieter Dirkszoon Keyser and Frederick de Houtman – two Dutch explorers/navigators who mapped the southern sky around Australia between 1595 and 1597.

It was included on a celestial globe published in 1597 or 1598 in Amsterdam by Plancius and his associate, Flemish cartographer and engraver Jodocus Hondius. After it’s introduction on Plancius’ globe, it also appeared in Uranometria, a star atlas published by Johann Bayer – a German celestial catrographer – in 1603.

Here, it appeared under the name “Apis Indica”. It also grouped with the other members of the “Johann Bayer family” of constellations, all of which appeared in Uranometria. These include Chamaeleon, Dorado, Grus, Hydrus, Indus, Musca, Pavo, Phoenix, Tucana, and Volans. The constellation also appears as part of the Chinese constellations, where it is known as the “Little Wonder Bird”.

In the 17th century, Ming Dynasty astronomer Xu Guangqi adapted the European southern hemisphere constellations when producing The Southern Asterisms. Combining Apus with some of the stars in Octans, he designated the stars in this area of the night sky into the constellation known as Yìquè (“Exotic Bird”). In 1922, Apus was included by the International Astronomical Union in the list of 88 constellations.

The southern constellation Apus and neighboring Deep Sky Objects. Credit: absoluteaxarquia.com
The southern constellation Apus and neighboring Deep Sky Objects. Credit: absoluteaxarquia.com

Notable Features:

Within the Apus constellation, there are 39 stars that are brighter than or equal to apparent magnitude 6.5. The most notable of these is Alpha Apodis. an orange giant star with a magnitude of 3.8, located roughly 411 light years away from Earth. Beta Apodis is also an orange giant, with a magnitude of 4.2. and located 158 light years from Earth. And Gamma Apodis , another orange giant, has a magnitude of 3.9 and is located 160 light years away.

Delta Apodis is a binary star system consisting of a red giant and an orange giant. Delta¹ has a magnitude of 4.7 and is located 765 light years away, while Delta² has a magnitude of 5.3 and is located 663 light years away. Then there is Theta Apodis, a variable red giant star with a maximum magnitude of 4.8 and a minimum of 6.1 that is located 328 light years away.

NO Apodis is a red giant that varies between magnitudes 5.71 and 5.95 and is located around 883 light-years away from Earth. This star shines with a luminosity that is approximately 2059 times greater than our Sun’s and has a surface temperature of 3568 K.

Apus is also home to a few Deep Sky Objects. These include the IC 4499 loose globular cluster (shown below), which is located in the medium-far galactic halo and has an apparent magnitude of 10.6. This object is rather unique in that its metallicity readings indicate that it is younger than most other globular clusters in the region.

This new NASA/ESA Hubble Space Telescope image shows the globular cluster IC 4499. Globular clusters are big balls of old stars that orbit around their host galaxy. It has long been believed that all the stars within a globular cluster form at the about same time, a property which can be used to determine the cluster's age. For more massive globulars however, detailed observations have shown that this is not entirely true — there is evidence that they instead consist of multiple populations of stars born at different times. One of the driving forces behind this behaviour is thought to be gravity: more massive globulars manage to grab more gas and dust, which can then be transformed into new stars. IC 4499 is a somewhat special case. Its mass lies somewhere between low-mass globulars, which show a single generation build-up, and the more complex and massive globulars which can contain more than one generation of stars. By studying objects like IC 4499 astronomers can therefore explore how mass affects a cluster's contents. Astronomers found no sign of multiple generations of stars in IC 4499 — supporting the idea that less massive clusters in general only consist of a single stellar generation. Hubble observations of IC 4499 have also helped to pinpoint the cluster's age: observations of this cluster from the 1990s suggested a puzzlingly young age when compared to other globular clusters within the Milky Way. However, since those first estimates new Hubble data been obtained, and it has been found to be much more likely that IC 4499 is actually roughly the same age as other Milky Way clusters at approximately 12 billion years old. Credit: ESA/NASA/HST
NASA/ESA Hubble Space Telescope image of the globular cluster IC 4499, located in the Apus constellation. Credit: ESA/NASA/HST

Then there’s NGC 6101, a 14th mangitude globular cluster located seven degree north of Gamma Apodis. Last, there is the spiral galaxy IC 4633, which is very faint due to its location well within the Milky Way’s nebulous disc.

Finding Apus:

For binoculars, take a look at Alpha Apodis. This 3.8 magnitude star is located 411 light years away from Earth. Now move on to Delta. It is a wide double star which is two orange 5th-magnitude members separated by 103 arc seconds and an easy split. Or try observing Theta – its a variable star whose brightness ranges from magnitude 4.8 to 6.1 in a period of 109 days.

For telescopes, take a look at more difficult binary star Kappa-1 Apodis. The brightest component of this disparate pair has a magnitude of 5.4 and the companion is 12th magnitude, 27 arcseconds away. Need more? Then turn your gaze towards Kappa-2 only 0.63 degrees from Kappa-1. Kappa-1 Apodis is a binary star approximately 1020 light years from Earth. The primary component, Kappa-1 Apodis A, is a blue-white B-type subgiant with a mean apparent magnitude of +5.40. It is classified as a Gamma Cassiopeiae type variable star and its brightness varies from magnitude +5.43 to +5.61. The companion star, Kappa-1 Apodis B, is a 12th magnitude orange K-type subgiant. It is 27 arc seconds from the primary.

For larger telescopes, wander off and look at NGC 6101 located about seven degrees north of Gamma. Here we have a small, 14th magnitude globular cluster! If you’re really good you can try for spiral galaxy IC 4633. It’s so faint it doesn’t even have a magnitude listing!

We have written many interesting articles about the constellation here at Universe Today. Here is What Are The Constellations?, Triangulum Australe, What Is The Zodiac?, and Zodiac Signs And Their Dates.

Be sure to check out The Messier Catalog while you’re at it!

For more information, check out the IAUs list of Constellations. and the Students for the Exploration and Development of Space page on Apus and Constellation Families.

The Andromeda Constellation

In the 2nd century CE, Greek-Egyptian astronomer Claudius Ptolemaeus (aka. Ptolemy) compiled a list of the then-known 48 constellations. His treatise, known as the Almagest, would be used by medieval European and Islamic scholars for over a thousand years to come. Thanks to the development of modern telescopes and astronomy, this list was amended by the early 20th century to include the 88 constellation that are recognized by the International Astronomical Union (IAU) today.

Of these, Andromeda is one of the oldest and most widely recognized. Located north of the celestial equator, this constellation is part of the family of Perseus, Cassiopeia, and Cepheus. Like many constellation that have come down to us from classical antiquity, the Andromeda constellation has deep roots, which may go all the way back to ancient Babylonian astronomy.

Continue reading “The Andromeda Constellation”

What Are The Constellations?

milky way constellations

What comes to mind when you look up at the night sky and spot the constellations? Is it a grand desire to explore deep into space? Is it the feeling of awe and wonder, that perhaps these shapes in the sky represent something? Or is the sense that, like countless generations of human beings who have come before you, you are staring into the heavens and seeing patterns? If the answer to any of the above is yes, then you are in good company!

While most people can name at least one constellation, very few know the story of where they came from. Who were the first people to spot them? Where do their names come from? And just how many constellations are there in the sky? Here are a few of the answers, followed by a list of every known constellation, and all the relevant information pertaining to them.

Definition:

A constellation is essentially a specific area of the celestial sphere, though the term is more often associated with a chance grouping of stars in the night sky. Technically, star groupings are known as asterisms, and the practice of locating and assigning names to them is known as asterism. This practice goes back thousands of years, possibly even to the Upper Paleolithic. In fact, archaeological studies have identified markings in the famous cave paintings at Lascaux in southern France (ca. 17,300 years old) that could be depictions of the Pleiades cluster and Orion’s Belt.

There are currently 88 officially recognized constellations in total, which together cover the entire sky. Hence, any given point in a celestial coordinate system can unambiguously be assigned to a constellation. It is also a common practice in modern astronomy, when locating objects in the sky, to indicate which constellation their coordinates place them in proximity to, thus conveying a rough idea of where they can be found.

Closeup of one section of the cave painting at the Lascaux cave complex, showing what could be Pleiades and Orion's Belt. Credit: ancient-wisdom.com
Closeup of the Lascaux cave paintings, showing a bull and what could be the Pleiades Cluster (over the right shoulder) and Orion’s Belt (far left). Credit: ancient-wisdom.com

The word constellation has its roots in the Late Latin term constellatio, which can be translated as “set of stars”. A more functional definition would be a recognizable pattern of stars whose appearance is associated with mythical characters, creatures, or certain characteristics. It’s also important to note that colloquial usage of the word “constellation” does not generally differentiate between an asterism and the area surrounding one.

Typically, stars in a constellation have only one thing in common – they appear near each other in the sky when viewed from Earth. In reality, these stars are often very distant from each other and only appear to line up based on their immense distance from Earth. Since stars also travel on their own orbits through the Milky Way, the star patterns of the constellations change slowly over time.

History of Observation:

It is believed that since the earliest humans walked the Earth, the tradition of looking up at the night sky and assigning names and characters to them existed. However, the earliest recorded evidence of asterism and constellation-naming comes to us from ancient Mesopotamia, and in the form of etchings on clay tablets that are dated to around ca. 3000 BCE.

However, the ancient Babylonians were the first to recognize that astronomical phenomena are periodic and can be calculated mathematically. It was during the middle Bronze Age (ca. 2100 – 1500 BCE) that the oldest Babylonian star catalogs were created, which would later come to be consulted by Greek, Roman and Hebrew scholars to create their own astronomical and astrological systems.

Star map showing the celestial globe of Su Song (1020-1101), a Chinese scientist and mechanical engineer of the Song Dynasty (960-1279). Credit: Wikipedia Commons
Star map showing the celestial globe of Su Song (1020-1101), a Chinese scientist and mechanical engineer of the Song Dynasty (960-1279). Credit: Wikipedia Commons

In ancient China, astronomical traditions can be traced back to the middle Shang Dynasty (ca. 13th century BCE), where oracle bones unearthed at Anyang were inscribed with the names of star. The parallels between these and earlier Sumerian star catalogs suggest they did no arise independently. Astronomical observations conducted in the Zhanguo period (5th century BCE) were later recorded by astronomers in the Han period (206 BCE – 220 CE), giving rise to the single system of classic Chinese astronomy.

In India, the earliest indications of an astronomical system being developed are attributed to the Indus Valley Civilization (3300–1300 BCE). However, the oldest recorded example of astronomy and astrology is the Vedanga Jyotisha, a study which is part of the wider Vedic literature (i.e. religious) of the time, and which is dated to 1400-1200 BCE.

By the 4th century BCE, the Greeks adopted the Babylonian system and added several more constellations to the mix. By the 2nd century CE, Claudius Ptolemaus (aka. Ptolemy) combined all 48 known constellations into a single system. His treatise, known as the Almagest, would be used by medieval European and Islamic scholars for over a thousand years to come.

Between the 8th and 15th centuries, the Islamic world experienced a burst of scientific development, reaching from the Al-Andus region (modern-day Spain and Portugal) to Central Asia and India. Advancements in astronomy and astrology closely paralleled those made in other fields, where ancient and classical knowledge was assimilated and expanded on.

The Northern Constellations. Credit: Bodel Nijenhuis Collection/Leiden University Library
The Northern Constellations. Credit: Bodel Nijenhuis Collection/Leiden University Library

In turn, Islamic astronomy later had a significant influence on Byzantine and European astronomy, as well as Chinese and West African astronomy (particularly in the Mali Empire). A significant number of stars in the sky, such as Aldebaran and Altair, and astronomical terms such as alidade, azimuth, and almucantar, are still referred to by their Arabic names.

From the end of the 16th century onward, the age of exploration gave rise to circumpolar navigation, which in turn led European astronomers to witness the constellations in the South Celestial Pole for the first time. Combined with expeditions that traveled to the Americas, Africa, Asia, and all other previously unexplored regions of the planet, modern star catalogs began to emerge.

IAU Constellations:

The International Astronomical Union (IAU) currently has a list of 88 accepted constellations. This is largely due to the work of Henry Norris Russell, who in 1922, aided the IAU in dividing the celestial sphere into 88 official sectors. In 1930, the boundaries between these constellations were devised by Eugène Delporte, along vertical and horizontal lines of right ascension and declination.

The IAU list is also based on the 48 constellations listed by Ptolemy in his Almagest, with early modern modifications and additions by subsequent astronomers – such as Petrus Plancius (1552 – 1622), Johannes Hevelius (1611 – 1687), and Nicolas Louis de Lacaille (1713 – 1762).

The modern constellations. color-coded by family, with a dotted line denoting the ecliptic. Credit: NASA/Scientific Visualization Studio
The modern constellations, color-coded by family, with a dotted line denoting the ecliptic. Credit: NASA/Scientific Visualization Studio

However, the data Delporte used was dated to the late 19th century, back when the suggestion was first made to designate boundaries in the celestial sphere. As a consequence, the precession of the equinoxes has already led the borders of the modern star map to become somewhat skewed, to the point that they are no longer vertical or horizontal. This effect will increase over the centuries and will require revision.

Not a single new constellation or constellation name has been postulated in centuries. When new stars are discovered, astronomers simply add them to the constellation they are closest to. So consider the information below, which lists all 88 constellations and provides information about each, to be up-to-date! We even threw in a few links about the zodiac, its meanings, and dates.

Enjoy your reading!

Sweet Sights for November Nights

Clear night ahead? Let’s see what’s up. We’ll start close to home with the Moon, zoom out to lonely Fomalhaut 25 light years away and then return to our own Solar System to track down the 7th planet. Even before the sky is dark, you can’t miss the 4-day-old crescent Moon reclining in the southwestern sky. Watch for it to wax to a half-moon by Thursday as it circles Earth at an average speed of 2,200 mph (3,600 km/hr). That fact that it orbits Earth means that the angle the Moon makes with the sun and our planet constantly varies, the reason for its ever-changing phase.

You'll see two and possibly three lunar "seas" tonight (Nov. 15). Only a portion of Mare Tranquilliitatis (Seas of Tranquility) is exposed. The large crater Janssen, 118 miles wide and 1.8 miles deep, is visible in binoculars. Credit: Virtual Moon Atlas / Legrande and Chevalley
You’ll see two and possibly three lunar “seas” tonight (Nov. 15). Only a portion of Mare Tranquilliitatis (Seas of Tranquility) is exposed. The large crater Janssen, 118 miles wide and 1.8 miles deep, is visible in binoculars. Credit: Virtual Moon Atlas / Legrande and Chevalley

With the naked eye you’ll be able to make two prominent dark patches within the crescent — Mare Crisium (Sea of Crises) and Mare Fecunditatis (Sea of Fecundity). Each is a vast, lava-flooded plain peppered with thousands of craters , most of which require a telescope to see. Not so Janssen. This large, 118-mile-wide (190-km) ring will be easy to pick out in a pair of seven to 10 power binoculars. Janssen is named for 19th century French astronomer Pierre Janssen, who was the first to see the bright yellow line of helium in the sun’s spectrum while observing August 1868 total solar eclipse.

Piscis Austrinus, the Southern Fish, has but one bright star, 1st magnitude Fomalhaut. It shines all by its lonesome in the south around 7 p.m. local time at mid-month. The star is located only 25 light years from Earth. Source: Stellarium
Piscis Austrinus, the Southern Fish, has but one bright star, 1st magnitude Fomalhaut. It shines all by its lonesome in the south around 7 p.m. local time at mid-month. The star is located only 25 light years from Earth. Source: Stellarium

English scientist Norman Lockyer also observed the line later in 1868 and concluded it represented a new solar element which he named “helium” after “helios”, the Greek word for sun. Helium on Earth wouldn’t be discovered for another 10 years, making this party-balloon gas the only element first discovered off-planet!

See the fish now? Greek mythology tells us that Piscis Austrinus is the "Great Fish", the parent of the two fish in the zodiacal constellation of Pisces the Fish. Source: Stellarium
See the fish now? Greek mythology tells us that Piscis Austrinus is the “Great Fish”, the parent of the two fish in the zodiacal constellation of Pisces the Fish. Source: Stellarium

Directing your gaze south around 7 o’clock, you’ll see a single bright star low in the southern sky. This is Fomalhaut in the dim constellation of Piscis Austrinus, the Southern Fish. The Arabic name means “mouth of the fish”. If live under a dark, light-pollution-free sky, you’ll be able to make out a loop of faint stars vaguely fish-like in form. Aside from being the only first magnitude star among the seasonal fall constellations, Fomalhaut stands out in another way — the star is ringed by a planet-forming disk of dust and rock much as our own Solar System was more than 4 billion years ago.

The planet Fomalhaut b orbits Fomalhaut inside a circumstellar disk of dust and rock, taking about 1,700 years to orbit. Brilliant Fomalhaut, represented by the small, white dot, has been masked from view, so astronomers could photograph the much fainter disk. Credit: NASA / ESA / Hubble Space Telescope
The planet Fomalhaut b orbits Fomalhaut inside a circumstellar disk of dust and rock, taking about 1,700 years to orbit. Brilliant Fomalhaut, represented by the small, white dot, has been masked from view, so astronomers could photograph the much fainter disk. Credit: NASA / ESA / Hubble Space Telescope

Within that disk is a new planet, Fomalhaut b, with less than twice Jupiter’s mass and enshrouded either by a cloud of dusty debris or a ring system like Saturn. Fomalhaut b has the distinction of being the first extrasolar planet ever photographed in visible light. The plodding planet takes an estimated 1,700 years to make one loop around Fomalhaut, with its distance from its parent star varying from about 50 times Earth’s distance from the sun at closest to 300 times that distance at farthest.

Shoot a diagonal across the Square of Pegasus to 4th magnitude Delta Piscium. Point your binoculars here and slide east to 4th magnitude Epsilon and 2° south to the planet Uranus shines at magnitude +5.7 and can be glimpsed with the naked eye from a dark sky site. Time shown is around 7 p.m. local time. See detailed map below. Source: Stellarium
Shoot a diagonal across the Square of Pegasus to 4th magnitude Delta Piscium. Point your binoculars here and slide east to 4th magnitude Epsilon and 2° south to the planet Uranus shines at magnitude +5.7 and can be glimpsed with the naked eye from a dark sky site. Time shown is around 7 p.m. local time. See detailed map below. Source: Stellarium

Next, we move on to one of the more remote planets in our own solar system, Uranus. The 7th planet from the sun, Uranus reached opposition — its closest to Earth and brightest appearance for the year — only a month ago. It’s well-placed for viewing in Pisces the Fish after nightfall high in the southeastern sky below the prominent sky asterism, the Great Square of Pegasus.

Wide-field binocular view of Uranus' travels now through next April. I've labeled two stars near the planet with their magnitudes - 5.5 and 6.0 - which are similar to Uranus in brightness, so you don't confuse them with the planet. The others are naked eye stars in Pisces. Source: Chris Mariott's SkyMap
Wide-field binocular view of Uranus’ travels now through next April. I’ve labeled several stars near the planet with their magnitudes, which are similar in brightness to Uranus, so you’ll know to tell them apart from the planet. The others are naked eye stars in Pisces. Source: Chris Mariott’s SkyMap

A telescope will tease out its tiny, greenish disk,  but almost any pair of binoculars will easily show the planet as a star-like point of light slowly marching westward against the starry backdrop in the coming weeks. Check in every few weeks to watch it move first west, in retrograde motion, and then turn back east around Christmas. For those with 8-inch and larger telescopes who love a challenge, use this Uranian Moon Finder to track the planet’s two brightest moons, Titania and Oberon, which glimmer weakly around 14th magnitude.

We’ve barely scratched the surface of the vacuum with these offerings; they’re just a few of the many highlights of mid-November nights that also include the annual Leonid meteor shower, which peaks Tuesday and Wednesday mornings (Nov. 17-18). So much to see!

Seeing Starspots: The Curious Case of XX Trianguli

Ever wonder what happens on the surface of other stars?

An amazing animation was released this week by astronomers at the Leibniz Institute for Astrophysics (AIP) in Potsam Germany, showing massive sunspot activity on the variable star XX Trianguli (HD 12545). And while ‘starspot’ activity has been seen on this and other stars before, this represents the first movie depicting the evolution of stellar surface activity beyond our solar system.

“We can see our first application as a prototype for upcoming stellar cycle studies, as it enables the prediction of a magnetic-activity cycle on a dramatically shorter timescale than usual,” says Leibniz Institute for Astrophysics Potsdam astronomer Andreas Kunstler in a recent press release.

The images were the result of a long term analysis of the star carried out using the twin STELLA (STELLar Activity) robotic telescopes based on Tenerife in the Canary Islands. The spectroscopic data was gathered over a period of six years, and this video demonstrates that, while other stars do indeed have sunspot cycles similar to our Sun, those of massive stars such as XX Tri are much more intense than any we could imagine here in our own solar system.

Image credit: Leibniz Institute for Astrophysics Potsdam (AIP)
STELLA on the hunt. Image credit:

Even the largest and closest of stars have a minuscule angular diameter –measured in milliarcseconds (mas, our 1/1,000ths of an arc second)—in size. For example, we know from lunar occultation timing experiments that the bright star Antares at 550 light years distant and 5 times the radius of our Sun is about 41 mas in size. At an estimated 910 to 1,500 light years distant and 10 times the radius of our Sun, XX Tri is probably comparable, at about 20 mas in size.

That’s tiny from our perspective, though the massive starspot depicted must be truly gigantic to see up close.

To image something on that scale, astronomers use a technique known as Doppler tomography gathered from high-resolution spectra. Over said six year span covering a period from July 2006 to April 2012, 667 viable spectra were gathered, covering 86 total rotational periods for the star. Incidentally, that’s not much longer than the average equatorial rotational period of our Sun—remember, as a ball of gas, the rotational period of our Sun varies with solar latitude—at about 22 days.

Our relatively sedate host star. image credit: Dave Dickinson
Our relatively sedate host star. Image credit: Dave Dickinson

The views compiled by the team show a pole facing, Mercator projection, and a spherical ‘real view’ of the star. Of course, to see XX Tri up close would be amazing, if a not a little intimidating with those massive, angry spots dappling its surface.

Watch the animation, and you can see the changing morphology of the spots, as they decay, merge and defuse again. Just how permanent is that massive pole spot? Why are we seeing spots across the pole of a star like XX Tri at all, something we never see on the Sun? Do other stars follow something analogous to Spörer’s Law and their own version of the 11-year sunspot cycle that we see on Sol?

Capabilities such as those demonstrated by STELLA may soon crack these questions wide open. Composed of two 1.2 meter robotic telescopes jointly operated by the Institute for Astrophysics at Potsdam and the Instituto de Astrofísica de Canarias (IAC), STELLA combines the capability of a wide-field photometric imager with that of a high-resolution spectrograph, ideal for this sort of analysis of remote stellar surfaces.

Image credit:
A diagram featuring the twin STELLA instruments. Image credit: Leibniz Institute for Astrophysics Potsdam (AIP)

Hey, here’s a crazy idea: turn STELLA loose on KIC 8462852 and see if the hypothesized ‘exo-comets’ or ‘alien mega-structures’ turn up… though it weighs in much smaller than XX Tri at 1.4x solar masses, KIC 8462852 is also about 1,400 light years distant, perhaps just doable using high resolution spectroscopy…

Image credit:
The location of XX Tri (also known as HIP 9630) in the northern sky. Image credit: created by the author using Stellarium planetarium software

Want to see XX Tri for yourself? An RS Canum Venaticorum variable orange giant star (spectral type K0 III) located in the constellation of Triangulum the Triangle, XX Tri shines at magnitude +8.5 and varies over about half a magnitude in brightness. Its coordinates are:

Right Ascension:  2 hours 3 minutes 47 seconds

Declination: 35 North 35 minutes 29 seconds

The more we learn about other stars, the more we understand about how to live with our very own sometimes placid, sometimes tempestuous host star.

Read more about the curious case of XX Trianguli:

On the Starspot Temperature of HD 12545

HD 124545: A Study in Spottedness

Spot evolution on the Star XX Triangulum (sic)

Does XX Trianguli look familiar? That might be because it was featured as the Astronomy Picture of the Day as ‘imaged’ by the Coude Feed Telescope on Kitt Peak way back when on November 2nd, 2003.

Mobile Launcher Upgraded to Launch NASA’s Mammoth ‘Journey to Mars’ Rocket

Looking up from beneath the enlarged exhaust hole of the Mobile Launcher to the 380 foot-tall tower astronauts will ascend as their gateway for missions to the Moon, Asteroids and Mars. The ML will support NASA’s Space Launch System (SLS) and Orion spacecraft during Exploration Mission-1 at NASA’s Kennedy Space Center in Florida. Credit: Ken Kremer/kenkremer.com
Story/photos updated[/caption]

KENNEDY SPACE CENTER, FL – NASA’s Mobile Launcher (ML) is undergoing major upgrades and modifications at the Kennedy Space Center in Florida enabling the massive structure to launch the agency’s mammoth Space Launch System (SLS) rocket and Orion crew capsule on a grand ‘Journey to Mars.’

“We just finished up major structural steel modifications to the ML, including work to increase the size of the rocket exhaust hole,” Eric Ernst, NASA Mobile Launch project manager, told Universe Today during an exclusive interview and inspection tour up and down the Mobile Launcher.

Indeed the Mobile Launcher is the astronauts gateway to deep space expeditions and missions to Mars.

Construction workers are hard at work upgrading and transforming the 380-foot-tall, 10.5-million-pound steel structure into the launcher for SLS and Orion – currently slated for a maiden blastoff no later than November 2018 on Exploration Mission-1 (EM-1).

“And now we have just started the next big effort to get ready for SLS.”

SLS and Orion are NASA’s next generation human spaceflight vehicles currently under development and aimed at propelling astronauts to deep space destinations, including the Moon and an asteroid in the 2020s and eventually a ‘Journey to Mars’ in the 2030s.

Floor level view of the Mobile Launcher and enlarged exhaust hole with 380 foot-tall launch tower astronauts will ascend as their gateway for missions to the Moon, Asteroids and Mars.   The ML will support NASA's Space Launch System (SLS) and Orion spacecraft  for launches from Space Launch Complex 39B the Kennedy Space Center in Florida.  Credit: Ken Kremer/kenkremer.com
Floor level view of the Mobile Launcher and enlarged exhaust hole with 380 foot-tall launch tower astronauts will ascend as their gateway for missions to the Moon, Asteroids and Mars. The ML will support NASA’s Space Launch System (SLS) and Orion spacecraft for launches from Space Launch Complex 39B at the Kennedy Space Center in Florida. Credit: Ken Kremer/kenkremer.com

The mobile launcher was originally built several years ago to accommodate NASA’s less powerful, lighter and now cancelled Ares-1 rocket. It therefore requires extensive alterations to accommodate the vastly more powerful and heavier SLS rocket.

“The ML was initially developed for Ares 1, a much smaller rocket,” Ernst explained to Universe Today.

“So the exhaust hole was much smaller.”

Whereas the Ares-1 first stage booster was based on using a single, more powerful version of the Space Shuttle Solid Rocket Boosters, the SLS first stage is gargantuan and will be the most powerful rocket the world has ever seen.

The SLS first stage comprises two shuttle derived solid rocket boosters and four RS-25 power plants recycled from their earlier life as space shuttle main engines (SSMEs). They generate a combined 8.4 million pounds of thrust – exceeding that of NASA’s Apollo Saturn V moon landing rocket.

Therefore the original ML exhaust hole had to be gutted and nearly tripled in width.

“The exhaust hole used to be about 22 x 22 feet,” Ernst stated.

“Since the exhaust hole was much smaller, we had to deconstruct part of the tower at the base, in place. The exhaust hole had to be made much bigger to accommodate the SLS.”

Construction crews extensively reworked the exhaust hole and made it far wider to accommodate SLS compared to the smaller one engineered and already built for the much narrower Ares-1, which was planned to generate some 3.6 million pounds of thrust.

“So we had to rip out a lot of steel,” Mike Canicatti, ML Construction Manager told Universe Today.

“For the exhaust hole [at the base of the tower], lots of pieces of [existing] steel were taken out and other new pieces were added, using entirely new steel.”

“The compartment for the exhaust hole used to be about 22 x 22 feet, now it’s about 34 x 64 feet.”

Looking down to the enlarged 64 foot wide exhaust hole from the top of NASA’s 380 foot-tall Mobile Launch tower.  Astronauts will board the Orion capsule atop the Space Launch System (SLS) rocket for launches from Space Launch Complex 39B the Kennedy Space Center in Florida.  Credit: Ken Kremer/kenkremer.com
Looking down to the enlarged 64 foot wide exhaust hole from the top of NASA’s 380 foot-tall Mobile Launch tower. Astronauts will board the Orion capsule atop the Space Launch System (SLS) rocket for launches from Space Launch Complex 39B the Kennedy Space Center in Florida. Credit: Ken Kremer/kenkremer.com

In fact this involved the demolition of over 750 tons of old steel following by fabrication and installation of more than 1,000 tons of new steel. It was also reinforced due to the much heavier weight of SLS.

“It was a huge effort and structural engineers did their job. The base was disassembled and reassembled in place” – to enlarge the exhaust hole.

“So basically we gutted major portions of the base out, put in new walls and big structural girders,” Ernst elaborated.

“And we just finished up that major structural steel modification on the exhaust hole.”

Top view across the massive 34 foot-wide, 64 foot-long exhaust hole excavated out of NASA’s Mobile Launcher that will support launches of the Space Launch System (SLS) rocket from Space Launch Complex 39B at the Kennedy Space Center in Florida.  Credit: Ken Kremer/kenkremer.com
Top view across the massive 34 foot-wide, 64 foot-long exhaust hole excavated out of NASA’s Mobile Launcher that will support launches of the Space Launch System (SLS) rocket from Space Launch Complex 39B at the Kennedy Space Center in Florida. Credit: Ken Kremer/kenkremer.com

Meanwhile the 380 foot-tall tower that future Orion astronauts will ascend was left in place.

“The tower portion itself did not need to be disassembled.”

IMG_8393_1a_KSC ML_Ken Kremer

The Ares rockets originally belonged to NASA’s Constellation program, whose intended goal was returning American astronauts to the surface of the Moon by 2020.

Ares-1 was slated as the booster for the Orion crew capsule. However, President Obama cancelled Constellation and NASA’s Return to the Moon soon after entering office.

Since then the Obama Administration and Congress worked together in a bipartisan manner together to fashion a new space hardware architecture and granted approval for development of the SLS heavy lift rocket to replace the Ares-1 and heavy lift Ares-5.

Sending astronauts on a ‘Journey to Mars’ is now NASA’s agency wide and overarching goal for the next few decades of human spaceflight.

But before SLS can be transported to its launch pad at Kennedy’s Space Launch Complex 39-B for the EM-1 test flight the next big construction step has to begin.

“So now we have just started the next big effort to get ready for SLS.”

This involves installation of Ground Support Equipment (GSE) and a wide range of launch support services and systems to the ML.

“The next big effort is the GSE installation contract,” Ernst told me.

“We have about 40+ ground support and facility systems to be installed on the ML. There are about 800 items to be installed, including about 300,000-plus feet of cable and several miles of piping and tubing.”

“So that’s the next big effort to get ready for SLS. It’s about a 1.5 year contract and it was just awarded to J.P. Donovan Construction Inc. of Rockledge, Florida.”

“The work just started at the end of August.”

NASA currently plans to roll the ML into the Vehicle Assembly Building in early 2017 for stacking of SLS and Orion for the EM-1 test flight.

View of NASA’s future SLS/Orion launch pad at Space Launch Complex 39B from atop  Mobile Launcher at the Kennedy Space Center in Florida.  Former Space Shuttle launch pad 39B is now undergoing renovations and upgrades to prepare for SLS/Orion flights starting in 2018. Credit: Ken Kremer/kenkremer.com
View of NASA’s future SLS/Orion launch pad at Space Launch Complex 39B from atop Mobile Launcher at the Kennedy Space Center in Florida. Former Space Shuttle launch pad 39B is now undergoing renovations and upgrades to prepare for SLS/Orion flights starting in 2018. Credit: Ken Kremer/kenkremer.com

The SLS/Orion mounted stack atop the ML will then roll out to Space Launch Complex 39B for the 2018 launch from the Kennedy Space Center.

Pad 39B is also undergoing radical renovations and upgrades, transforming it from its use for NASA’s now retired Space Shuttle program into a modernized 21st century launch pad. Watch for my upcoming story.

Artist concept of the SLS Block 1 configuration.  Credit: NASA
Artist concept of the SLS Block 1 configuration mounted on the Mobile Launcher. Credit: NASA

Stay tuned here for Ken’s continuing Earth and planetary science and human spaceflight news.

Ken Kremer

United Launch Alliance Atlas V rocket with MUOS-4 US Navy communications satellite poised at pad 41 at Cape Canaveral Air Force Station, FL, set for launch on Sept. 2, 2015. EDT. View from atop NASA’s SLS mobile launcher at the Kenned Space Center. Credit: Ken Kremer/kenkremer.com
View from atop NASA’s SLS mobile launcher at the Kennedy Space Center, looking out to United Launch Alliance Atlas V rocket with MUOS-4 US Navy communications satellite poised at pad 41 at Cape Canaveral Air Force Station, FL, ‘prior to launch on Sept. 2, 2015. EDT. Credit: Ken Kremer/kenkremer.com

Book Review: The Seventh Landing — Going Back to the Moon, This Time to Stay

Can you remember back to your first love? The one that left you in tears, wondering what ever caused such a disaster. Well, that feeling might come back to you if you read Michael Carroll’s “The Seventh Landing.” For you see, this book anticipates the imminent Constellation program of 2009 that was going to return the United States to the Moon and then on to Mars. We know what happened instead and we know a few tears must have been shed, perhaps even yours.

Yes, this book is all about the Constellation program and its Ares I and ARES V launch vehicles. But more than that, and what makes it still applicable today, is that the book really gets into a lunar landing program as the next step in humankind’s expansion off of Earth — and how it’s the logical precursor to the next step: a settlement on Mars.

This logical progression jumps right out via the table of contents. First there’s an excellent chapter that recovers what’s already transpired; the good and bad of both the Apollo program and the early Soviet space program. The writing style and copious quantities of vintage photographs bring a sense of immediacy and presence.

The second chapter takes you to the promised land. This land is full of large expendable launch vehicles; human rated and ready to transport material and supplies. Here’s where the value of this book continues on to today. That is, the book provides a systems analysis point of view on, for instance, why various engines would be better or how to use ping pong balls to design a lunar capsule. With this, the reader can start to get a grasp on the complexity of this undertaking. Interesting yes, but what about that purpose again? Oh yes, it was to put humans on the Moon. Well that’s the book’s next chapter.

Bring on the Shackleton crater, the nights of -233C and the dust. Lots and lots of dust. As it states, sure there may be some engineering challenges but hey, we’ve been to the Moon already and we’ve been continuing to research it nearly non-stop so we should certainly be able to go back there to live; even if it won’t be easy.

The remainder of the book is somewhat like a lover after their first kiss; all hopes and aspirations. The chapters progress on to the reasons for returning to the Moon or what to do once there. Then, of course, there’s that final question that remains and which the book outlines but doesn’t answer. That is, “Is the Moon really the next step for humanity or should we go Mars direct?” Well, since 2009, there’s been lots of discussion on this topic though as we’ve seen, there’s been very little substance. So in a sense, this book is still a wonderful jumping off point for someone who wants to understand where things lie with regard to the expansion of humans into space even if it won’t be via the launch vehicles of the Constellation program.

Yes, this book has lots of technical detail on elements needed for a Moon program. What also becomes apparent on reading the book is that the author is also an award winning artist of space themes. Thus, the reader receives a reward simply by viewing the book’s images. For instance, it’s got a wonderful image of Werner Von Braun’s plan of space “boats” winging down through the Martian atmosphere. Or, there’s a rendered image of an Altair lander doing a final approach to an established base on the rim of Shackleton. Many other renderings take the reader out from the germane and into a visual playground of possibilities. Certainly, if the Constellation program had been funded, then there’s a good chance that some of these images might be close to reality. But, we will just have to be content with the images for now.

Sometimes being content is the best we can do. For example, perhaps you`ve keep secreted away an old photograph of that first love. It’s so far away that no one will ever know but you. And maybe on a dark lonely night you pull out that photograph and imagine what might have been. Or maybe on that dark night you pull out a copy of Michael Carroll’s “The Seventh Landing” and dream about what might have been. And, of course, you will remember that tomorrow is a new day when anything might come true, even dreams.

Find out more about the book at Springer’s website, and learn more about the author, Michael Carroll, at his website.

How Low Can You Go? Take the Great Square Challenge

Cast your gaze up, up, up on the next dark, moonless night and stare into the Great Square of Pegasus. How many stars do you see? Zero? Two? Twenty? If you’d like to find out how dark your sky is, read on. 

The Great Square, one of the fall sky’s best known star patterns, rides high in the south at nightfall in mid-December. It forms part of the larger figure of Pegasus the Winged Horse. For our purposes today, we’re going to concentrate on what’s inside the square.

Bounded by Alpheratz (officially belonging to adjacent Andromeda), Scheat, Markab and Algenib, the Great Square is about 15° on a side or one-and-a-half balled fists held at arm’s length.

At first glance, the space appears empty, but a closer look from all but the most light polluted skies will reveal a pair 4th magnitude stars in the upper right quadrant of the square. Fourth magnitude is about the viewing limit from a bright suburban location.

Astronomers use the magnitude scale to measure star and planet brightness. Each magnitude is 2.5 times brighter than the one below it. Aldebaran, which shines at 1st magnitude, is 2.5 times brighter than a 2nd magnitude star, which in turn is 2.5 times brighter than a 3rd magnitude star and so on.

Moonlight and especially light pollution reduce the number of stars we can see in the night sky. This specially prepared map shows slices of sky based on amateur astronomer and author John Bortle's Dark Sky Scale. Classes range from 1 (excellent with stars fainter than 7th magnitude visible) to 9 (inner city with a limiting magnitude of 4). Click for more detailed descriptions of each class and rate your own sky. Credit: International Dark Sky Association
Moonlight and especially light pollution reduce the number of stars we can see in the night sky. This specially prepared map shows slices of sky based on amateur astronomer and author John Bortle’s Dark Sky Scale. Classes range from 1 (excellent with stars fainter than 7th magnitude visible) to 9 (inner city with a limiting magnitude of 4). Click for more detailed descriptions of each class and rate your own sky. Credit: International Dark Sky Association

A first magnitude star is 2.5 x 2.5 x 2.5 x 2.5 x 2.5 (about 100) times brighter than a 6th magnitude star. The bigger the magnitude number, the fainter the star. From cities, you might see 3rd magnitude stars if you can block out stray lighting, but a dark country sky will deliver the Holy Grail naked eye limit of magnitude 6. Skywatchers with utterly dark conditions might glimpse stars as faint 7.5. My own personal best is 6.5.

With each drop in magnitude the number of stars you can see increases exponentially. There are only 22 first magnitude or brighter stars compared to 5,946 stars down to magnitude 6.

What appears blank at first is filled with stars -- 26 of them down to magnitude 6.3 are visible inside the Great Square from a dark sky site. How many can you see? Click for a large version. Source: Stellarium
What appears blank at first is filled with stars — 26 of them down to magnitude 6.3 are visible inside the Great Square from a dark sky site. How many can you see? Click for a larger version. Source: Stellarium

Ready to stretch your sight  and rate your night sky? Step outside at nightfall and allow your eyes to dark-adapt for 20 minutes. With a copy of the map (above) in hand, start with the brightest stars and work your way to the faintest. Each every small step down the magnitude ladder prepares your eyes the next.

With a little effort you should be able to spot the four 4th magnitude range stars. At magnitude 5, you’ll work harder. Moving beyond 5.5 can be very challenging. I revert to averted vision to corral these fainties. Instead of staring directly at the star, play your eye around it. Look a bit to this side and that. This allows a rod-rich part of the retina that’s excellent at seeing faint stuff play through the scene and snatch up the faintest possible stars.

Magnitude scale showing the limits of the eye, binoculars and telescopes. Credit: Dr. Michael Bolte, UCO/Lick Observatory
Magnitude scale showing the limits of the eye, binoculars and telescopes. Credit: Dr. Michael Bolte, UCO/Lick Observatory

From my house I can pick out about dozen points of light inside the Square on a moonless night. How many will you see? Once you know your magnitude limit, compare your result to John Bortle’s Dark Sky Scale … and weep. No, just kidding. But his Class 1 excellent sky includes a description of seeing stars down to magnitude 8 and the summer Milky Way casting shadows.

Hard to believe that before about 1790, when gas lighting was introduced in England, Class 1 skies were the norm across virtually the entire planet. Nowadays, most of us have to drive a hundred miles or more to experience true, untrammeled darkness.

Have fun with the challenge and let us know in the comments area how you do. Here’s hoping you find the Great Square far from vacant.