Pedro Castle, Monday March 10th, 7.00 p.m.

High overhead at viewing time lies the constellation Auriga.
The Charioteer (possibly Erechthonius, son of Vulcan) is among the brightest northern constellations, it lies midway between Perseus and Ursa Major in a region crossed by the Milky Way, and is the site of the galactic anticenter (the point in the sky diametrically opposite the center of the Galaxy). Gamma Aur, or El Nath, is shared with Taurus and is universally referred nowadays as Beta Tau.
Its brightest star is Capella, which is associated with the mythological she-goat Amalthea. The three stars ε Aurigae, ζ Aurigae and η Aurigae are called Haedi (the Kids). Aurigae and Zeta Aurigae are remarkable eclipsing binaries.
ε Aurigae and ζ Aurigae are peculiar binary stars. The orbital period of ε Aurigae is approximately 27 years, with an eclipse duration of about 18 months. The visible companion is a yellowish F-class supergiant. The type of the other star is not known. ζ Aurigae has a period of 970 days, the primary is a K-class supergiant and the secondary is a B-class main sequence star. Both these systems present a rare stage of binary evolution, as the components are in a short and active evolutionary stage.
Auriga has many open clusters and other objects because the Milky Way runs through it. The three brightest open clusters are M36, M37 and M38, all of which are visible in binoculars or a small telescope in suburban skies. A larger telescope resolves individual stars. The clusters are about 4100, 4400, and 4200 light years distant, respectively. Their apparent visual magnitudes are 6.3, 6.2, and 7.4, respectively.
Capella (α Aur / α Aurigae / Alpha Aurigae) is the brightest star in the constellation, and eleventh brightest star in the sky. Although it appears as a single point to the naked eye, Capella is actually a bright close binary pair of yellow giant stars along side a second, fainter binary.
A yellow star, it traditionally marks the left shoulder of the constellation's eponymous charioteer, or sometimes the goat that the charioteer is carrying. It is closer to the north celestial pole than any other first magnitude star (Polaris is only second magnitude) and as a result has played a significant role in many mythological writings. A tablet dating back to 2000 BC refers to Capella.
Astronomically, Capella's interest lies in the fact that it is an easily-studied non-eclipsing spectroscopic binary star. These two giant G-class stars have luminosities of around 50 and 80 times that of the Sun and lie less than 100 million km apart with an orbital period of 104.02 days. The stars were probably of spectral class A during their main sequence, similar to Sirius, and are in the process of becoming red giants in a few million more years as they continue to expand, cool, and brighten. Capella is a source of X-rays, probably due to surface magnetic activity on one of the pair. The Capella binary was the first star system to be imaged using a long baseline optical astronomical interferometer in observations by COAST in 1995.
The central stars also have a faint companion that is itself a double star, consisting of two M-class red dwarf stars, that orbit at around a light year away from the main pair.
In Australian Aboriginal mythology, Capella was Purra, the kangaroo, pursued and killed by the nearby Gemini twins or by the Orion hunter, or near the Orion belt twins canoe.
To the Bedouin people of the Negev and Sinai, Capella is known as al-'Ayūg, 'the dandy', in its role as pointing out the position of the Pleiades -its name more fully al-'Ayūg ath-Thurayyā 'dandy of the Pleiades'.

On the night,Mars will be high overhead, with Saturn rising in the east, close to the brightest star in Leo, Regulus.
clear skies
Nick

Pedro Castle, Monday February 11th

As darkness falls on Monday the bright star Aldebaran can be seen directly overhead.
Aldebaran is the brightest star in the constellation Taurus and one of the brightest stars in the nighttime sky. It has the Bayer designation Alpha Tauri. Because of its location in the head of Taurus, it has historically been called the Bull's Eye. Aldebaran has the appearance of being the brightest member of the more scattered Hyades cluster, which is the closest star cluster to Earth. However, it is merely located in the line of sight between the Earth and the Hyades, and is actually an independent star.
In 1997, a possible substellar companion was reported, with a mass at least 11 times that of Jupiter with an orbital period of around 2 years, however this has not been confirmed.
Aldebaran is a K5 III star, which means it is orangish, large, and has moved off of the main sequence after exhausting the hydrogen fuel in its core. It has a minor companion (a dim M2 dwarf orbiting at several hundred AU). Now primarily fusing helium, the main star has expanded to a diameter of approximately 5.3 × 107 km, or about 38 times the diameter of the Sun.
The Hipparcos satellite has measured it as 65.1 light years away, and it shines with 150 times the Sun's luminosity. With an apparent magnitude of 0.87, it is the 14th brightest star.
The name Aldebaran comes from the Arabic (الدبران al-dabarān) meaning "the follower" and refers to the way the star follows the Pleiades star cluster in its nightly journey across the sky.
In Persia it was known as Satvis and Kugard.[4]
It is known as 畢宿五 (Bìxiùwŭ, the Fifth Star of the Net) in Chinese.
Aldebaran is identified as the lunar mansion Rohini in Hindu astronomy and as one of the twenty-seven daughters of Daksha and the wife of the god Chandra.
The Romans called it Palilicium.
For the Dakotas (a branch of the Native American Sioux tribe), Aldebaran took on a heroic aspect. The young star was the child of the sun and the lady Blue Star. One day, he desired to hunt the white buffalo (the Pleiades). After he pulled up a sapling to make a spear, a hole was made in the ground and he could see all the people of Earth down below. The white buffalo took this chance to push him through. He was found by an old woman and was to be known as Old Woman's Grandson. On Earth, he killed many strange monsters that had been troubling the Native Americans; one monster of which was a serpent that caused drought. The young hero killed the serpent, releasing a great stream of water that became the Mississippi River. In time, Old Woman's Grandson remembered the white buffalo and returned to hunting him in the sky to fulfill his destiny.
For the Seris of northwestern Mexico, this star is providing light for the seven women giving birth (Pleiades).
Noticeably redder, and brighter, is the nearby planet Mars.
Mars is close to the β (beta) star of Auriga on the illustration above.
Called Menkalinan, it is a double star consisting of two blue white giant A2 class stars. They have magnitudes of 1.9 and 2.7 and are 90 light years distant.

January 11th 2008

Although the eye is drawn to bright Mars and the rising winter constellations, almost directly overhead as darkness falls is the small, faint constellation of Aries.
Aries is one of the least conspicuous of the zodiacal constellations, and has only two stars above third magnitude. These are Hamal and Sheratan, the Alpha and Beta stars of the constellation. Unusually, these two stars not only appear to be close together in the sky, but actually are: they lie just six light years from one another.
The Hipparcos satellite indicates that Hamal is about 65.9 light-years from Earth. Combined with its intrinsic brightness, this relatively small distance makes the star shine at an apparent magnitude of 2.01, the 47th brightest star in the sky.
Beta Arietis is the Ram's second horn. It also has the traditional name Sharatan (or Sheratan or Sheratim), and the Flamsteed designation 6 Arietis.
Al Sharatan means "the two signs", a reference to the star having marked the vernal equinox together with its binary partner Gamma Arietis several thousand years ago. It is 59.6 light years from Earth.
Gamma Arietis, Mesarthrim, shines third among the stars of the flat triangle that make the classical figure of Aries, the Ram (for that reason gaining the Gamma designation). The name (derived from Arabic) originally came from the same root as that for the Beta star, Sheratan (meaning "the two"), but was corrupted by mistranslations into its current form.
Gamma Arietis is a beautiful double star, which was discovered quite by chance in 1664 when astronomer, Robert Hooke, was following the motion of a comet. Gamma Arietis is one of the earliest double stars on record to have been found with the aid of a telescope.
Teegarden's star, a recent (2003) discovery is also in the constellation. It is one of Sun's closest neighbors at around 12 light years away. It appears to be a red dwarf, a class of low temperature and low luminosity stars. This would explain why it was not discovered earlier, since it has an apparent magnitude of only 15.4 (and an absolute magnitude of 17.47).
Teegarden's Star was discovered on images taken by the NEAT program operated by NASA. Its name comes from its principal discoverer, Dr. Bonnard Teegarden, an astrophysicist at NASA's Goddard Space Flight Center.
It is thought to be quite likely that many other dim and easily overlooked red dwarf stars exist in the nearest 20 light years, as stellar population surveys show their count to be quite lower than otherwise expected.
Although dim, Aries is one of the oldest and most revered of all constellations. The ancient Babylonians, Egyptians, Persians and Greeks all called this group of stars "The Ram." It is the Zodiac's first constellation since the Sun, at one time, was entering Aries on the day of the vernal equinox...the moment when it crosses from the southern to the northern half of the celestial sphere. However, because of the Earth's precession, the Sun is now in Pisces at the vernal equinox. Nevertheless, Aries is still considered to be the symbolic first constellation of the Zodiac and Right Ascension continues to be measured from the first point of Aries.
In a bygone age, the Egyptians associated Aries with Amon-Re, the ram-headed supreme Sun God who symbolized power and fertility. The Mesopotamians' name for the constellation meant a military leader or prince. In Hebrew tradition, the ram represented the death-defying blood of the lamb smeared on the doorways as part of the original Passover, which preceded the Hebrew Exodus from Egypt. The Greeks related Aries to the story of the Golden Fleece, the hide of the flying ram that Jason (with the help of his beloved Medea) spirited away from the serpent in the Grove of Aries. This constellation is mentioned in "Phaenomena," authored by the Greek poet Aratus, which dates from the Third Century B.C., and Ptolemy, the great astronomer who lived and worked in Egypt during the Second Century A.D., cataloged this constellation.
The present name of this Zodiac Sign is Roman in origin, Roman mythology having been adopted from that of the Ancient Greeks. This faint and tiny cluster of stars first appeared on monetary coin in 6 A.D.
clear skies
Nick

Wednesday, 12th December 6.30 p.m.

Directly over head as darkness fall is the constellation Pegasus. Four stars form almost a perfect square that are about the same brightness. This is the "Great Square of Pegasus."
The "Great Square" forms the body of the Winged Horse. To connect the rest of Pegasus, you'll need to use the right side of the "square." Pegasus is flying upside down across the sky. From Markab (lower right corner) extends the head of the Winged Horse. The two front legs of Pegasus can be found off the star Scheat (upper right corner). The star Alpheratz is shared by two constellations, Pegasus and Andromeda. The star is actually considered to be a star of Andromeda.
51 Pegasi, a star in this constellation, is the first Sun-like star known to have an extrasolar planet. IK Pegasi is the nearest supernova candidate.
In Andromeda is the most famous deep sky object , M31.This is the Andromeda Galaxy, one of the most distant objects visible to the naked eye. It is an enormous spiral galaxy much like the Milky Way and is approximately 2.5 million light-years away.
Andromeda is the largest galaxy of the Local Group, which consists of the Andromeda Galaxy, the Milky Way Galaxy, the Triangulum Galaxy, and about 30 other smaller galaxies. Although the largest, it may not be the most massive, as recent findings suggest that the Milky Way contains more dark matter and may be the most massive in the grouping. However, recent observations by the Spitzer Space Telescope revealed that M31 contains one trillion (1012) stars, greatly exceeding the number of stars in our own galaxy. 2006 estimates put the mass of the Milky Way to be ~80% of the mass of Andromeda, which is estimated to be 7.1×1011 solar masses.
Bright Mars rises a little later that night, making its closest approach to Earth since 2005. Not often do we get a close look at Mars. It’s a small world to begin with, about half the diameter of Earth, and it spends most of the time far away on the other side of its orbit from us. Mars usually ranks as one of the most disappointing objects in amateur astronomy — a tiny, featureless orange blob. The only time we get a decent look at its surface markings, clouds, dust storms, and changing polar caps is for a couple of months every two years, when Mars comes closest (around its date of opposition).
This time around, Mars maxes out at 15.9 arcseconds when it passes closest to Earth on December 18th. That's nowhere near its record-breaking apparent diameter of 25.1" in August 2003. Even so, it's bigger than Mars will appear again until 2016.
Contrary to rumor, Comet 17P/Holmes has not faded away. From any dark starry-skied observing site, it remains visible to the naked eye. Although the comet is not as bright as it was when it exploded in late October, it makes up for its lack of surface brightness by sheer size: the comet is huge! It looks like a faint Moon-sized puff of cloud in the middle of the constellation Perseus--a really splendid sight.
For patient and wakeful people, the Geminid meteor shower can be viewed the night of December 13–14, with good prospects the following night as well.

Monday 12th November Pedros Castle 6:30 PM

There are few bright stars in the sky this time of year, which makes it difficult to easily make out many of the constellations.
However, one of the most distinctive constellations in the northern hemisphere, Cassiopeia, the vain Queen, is in the north when it is dark.
Cassiopeia, the wife of King Cepheus, ruler of Aethiopia, was beautiful, arrogant and vain, and it was these latter two characteristics which were to lead to her downfall. Her continual boast that both she and her daughter Andromeda were more beautiful than the sea nymphs, daughters of Nereus, the sea god, brought the wrath of Poseidon, ruling god of the sea, upon the kingdom of Aethiopia. Trying to avert such a fate, Cepheus and Cassiopeia consulted a wise oracle, who told them that the only way to appease the sea gods was to sacrifice their daughter. Accordingly, Andromeda was chained to a rock at the sea's edge, and left there to helplessly await her fate at the mercy of the sea monster. But Perseus arrived in time and saved Andromeda. Poseidon considered that Cassiopeia should not escape punishment entirely, and placed her in the heavens in such a position that she circles the celestial pole in an upside-down position for half the time.
Cassiopeia contains two stars visible to the naked eye that rank among the brightest in the galaxy, ρ (Rho) Cassiopeiae and V509 Cassiopeiae.
Rho Cassiopeiae (also Rho Cas) is a yellow hypergiant in the Cassiopeia constellation. It is about 8-10,000 light years away, yet can still be seen by the naked eye (in the Northern Hemisphere only), as it is 550,000 times brighter than the Sun. The surface diameter is 738 times larger than our sun's. Astronomers think Rho Cas may go supernova in the not too distant future, because it will have consumed most of the nuclear fuel in its core.
If we were to observe Earth's Sun from Alpha Centauri, it would appear to be in Cassiopeia.

The planets this month are late night objects. Mars rises shortly before midnight at the beginning of November, and will be visible just above the horizon by 10.30 on the night of the viewing.

Venus and Saturn are visible in the early morning sky.

Sunday 14th October 7.00 p.m. Pedros Castle

Directly overhead as darkness falls can be seen the distinctive shape known as the Summer Triangle, which consists of the stars Vega, Deneb and Altair. This noticeable pattern is known as an astronomical asterism, a group of stars seen in Earth's sky which is not an official constellation. The triangle connects the constellations of Aquila, Cygnus, and Lyra.
The largest of these three constellations is Cygnus, the Swan, also known as the Northern Cross. Cygnus contains several bright stars.
Deneb, α Cygni, is an extremely brilliant star, very prominent despite its distance (3230 light years). The blue supergiant forms the swan's tail, the upper end of the Northern Cross. It’s also the 18th brightest star in the sky.
Albireo, β Cygni, is at the swan's beak. It is one of the most beautiful double stars of the sky, a golden star easily distinguishable in a small telescope from its blue companion.
Lyra, dominated by its bright star Vega, is a much smaller constellation than Cygnus.
Vega is the second brightest star of the northern hemisphere (after Arcturus) and the fifth brightest star in all. It lies at a distance of only 25.3 ly. It was the first star to be photographed.
Aquila is a much harder pattern to distinguish, although Altair is easy to spot. Altair is located 17 light years away from Earth (about 159 trillion kilometers) and is one of the closest stars visible to the naked eye.

Behind the Summer Triangle lies some of the vast star fields of our Milky Way Galaxy, containing literally billions of stars. The dark band across the middle that seems to divide the stars is actually interstellar dust, which absorbs more visible light than it emits and so appears dark.

Jupiter is the only visible planet in the evening sky this month, shining bright in the south west.

Autumnal equinox falls on the 23rd, when the Sun can be observed to be directly above the Earth's equator. Night and day are nearly of the same length, and this signals the end of the summer months and the beginning of winter.

Friday 14th September Pedros Castle 7:00 PM

Friday, 14th September is our viewing date this month, 7.00 p.m. at Pedro Castle.
Sagittarius, the archer — whose brightest stars form the shape of a teapot — is now prominent in the southern sky.
Sagittarius has drawn his bow, and his arrow is pointing at Antares, the bright red heart of Scorpius, the scorpion. The archer is avenging Orion, who was slain by the scorpion's sting.
The constellation Sagittarius is one of the most interesting regions of the sky. The center of our Milky Way galaxy lies inside Sagittarius, about 26,000 light-years away. The constellation also contains several globular clusters — tightly packed collections of hundreds of thousands of stars.
The Milky Way is the galaxy where the Solar System (and Earth) is located. It is a barred spiral galaxy of a Local Group of galaxies within the Virgo Supercluster. The main disk of the galaxy is about 80,000 to 100,000 light-years in diameter, about 250,000 to 300,000 light-years in circumference, and outside the Galactic core, about 2,300–2,600 light-years in thickness. The galaxy is estimated to contain 200 billion stars but this number may be as high as 400 billion if small-mass stars predominate.
As a guide to the relative physical scale of the Milky Way, if the galaxy were reduced to 130 km (80 mi) in diameter, the solar system would be a mere 2 mm (0.08 inches) in width.
The Lagoon Nebula (also known as Messier Object 8 (M8) and NGC 6523) and the Trifid Nebula (also known as Messier 20 and NGC 6514) are giant interstellar clouds and H II regions.
An H II region is a cloud of glowing gas and plasma, sometimes several hundred light-years across, in which star formation is taking place. Young, hot, blue stars which have formed from the gas emit copious amounts of ultraviolet light, ionising the nebula surrounding them.
Nunki, 224 light years away from us, is the second brightest star in the constellation Sagittarius; its Babylonian name is of unknown origin. Blue-white Nunki is a B star and one of the hotter of the bright stars, radiating much of its light in the ultraviolet. Typical of its breed, it is a fast spinner, rotating with a speed of over 200 km/s – 100 times that of our Sun. Although still on the main sequence, Nunki is much more massive than the Sun and will exhaust its internal fusion reserves in another 50 million years or so.
Jupiter is the only planet visible in the evening sky, brilliant and unmistakable in Scorpius, above Antares. Early risers will be able to see Mars overhead before the dawn, and Venus and Saturn in the east.

Wednesday 15th August :730 PM Pedros Castle

CAYMAN ISLANDS ASTRONOMICAL SOCIETY
NEWSLETTER AUGUST 2007
We will aim to meet this month on Wednesday, 15th August, 7.30.p.m. at Pedro Castle, weather permitting.
The Perseid Meteor Shower occurs on August 12-13th. This year the new moon will leave the sky dark. Look to the eastern sky in the constellation Perseus. Between 2 a.m. and dawn on August 13, if you get away from city lights, you could see hundreds of meteors.
This is one of the best showers of the year. The Perseids are a result of debris in space left by comet Swift-Tuttle. Although the comet is nowhere near Earth, the comet's wide tail does intersect Earth's orbit. We glide through it every year in July and August. Tiny bits of comet dust hit Earth's atmosphere traveling 132,000 mph. At that speed, even a tiny smidgen of dust makes a vivid streak of light--a meteor--when it disintegrates. The shower is most intense when Earth is in the dustiest part of the tail.

The mythological illustration that I used last month included the constellation Scorpius, more schematically shown above.
Jupiter, the fourth brightest object to light up the heavens, after the sun, moon, and Venus, shines unmistakably in the southern part of the sky, and serves as a guide to the Scorpion.
This is a distinctive constellation with its wide head and body curving to its tail. Glowing with a reddish hue at the heart of this asterism is the bright star Antares, the sixteenth brightest in the sky, although out shone this month by close Jupiter.
Antares is in the middle of the scorpion's curving body and rivals Mars in its reddish tint. This brilliant red star is one of the behemoths of our stellar neighborhood. If you placed it at the center of our own solar system, it would swallow Mercury, Venus, Earth, and Mars, and almost reach Jupiter.
The Scorpion was sent by Gaia to kill Orion when Orion boasted he would slay all the animals of the Earth; now Orion and Scorpius circle each other on opposite sides of the sky.
The Chinese included these stars in the Azure Dragon, a powerful but benevolent creature whose rising heralded spring, and in Maori mythology, this constellation can be Maui's magic jawbone used to fish up the North Island of New Zealand.

Tuesday 17th July 7:30 PM at Pedros Castle

CAYMAN ISLANDS ASTRONOMICAL SOCIETY
NEWSLETTER JULY 2007
The viewing session this month will be on Tuesday 17th, 7.30 p.m. at Pedro Castle.
Last months illustration showed, as well as the featured constellation Crux, Centaurus (Latin for centaur). One of the 48 constellations listed by Ptolemy, it counts also among the 88 modern constellations. This southern constellation is one of the largest in the sky. This half man, half horse marked the southernmost constellation visible to astronomers of classical times.
The constellation, as depicted above, represents the death of Lupus, the wolf, on the spear of a heavenly centaur. Early representations of the two constellations actually reveal the figure of a centaur holding a staff called the thyrsus and a wolf. The thyrsus is covered with ivy and grape vines and tipped with a pine cone. These are the ingredients of the godly drink called nectar. The she-wolf is Selene, the moon, who helps in the preparation of the drink.


Centaurus contains the closest star to the Sun, Alpha Centauri, 4.4 light years away. Alpha Centauri is also known as Rigil Kentaurus, from the Arabic meaning ‘centaur’s foot’. To the naked eye it appears as the third-brightest star in the sky, but a small telescope reveals it to be double, consisting of two yellow stars like the Sun. A third, much fainter companion star is called Proxima Centauri because it is slightly closer to us than the other two. Beta Centauri is called Hadar, from an Arabic name signifying one member of a pair of stars. Alpha and Beta Centauri mark the front legs of the centaur, and they act as pointers to Crux, the Southern Cross, which lies under the centaur’s rear quarters. Centaurus also contains the largest and brightest globular star cluster visible from Earth, Omega Centauri.
Gamma Centauri, Muhlifain, is a double star approximately 130 light years from Earth, which consists of two spectral type A0 stars each of apparent magnitude +2.9. For the resolution of the double star system a telescope of at least 15 centimeters in aperture is necessary. They have an orbital period of 83 years.
The star forms the hip or backside of the Centaur and is found directly north of the Southern Cross.
Saturn and Venus will be low in the west on viewing night, close to the crescent moon. Both will disappear from the night sky at months end, leaving brilliant Jupiter to shine alone.

Monday 18th June 7:30 PM Pedros Castle

CAYMAN ISLANDS ASTRONOMICAL SOCIETY
NEWSLETTER JUNE 2007
We will aim to meet this month on Monday, 18th June, 7.30.p.m. at Pedro Castle, weather permitting.
Crux, the Southern Cross will be visible for the rest of this month. On the night of the 18th, the constellation will be more upright than in the diagram above, hanging above the southern horizon.
Crux is the smallest constellation in the sky, but one of the most celebrated. The early Portuguese navigators saw it as a symbol of their faith, and the mystery of the unknown lent it an additional charm in the minds of those from whom the southern skies were hidden. There are other cross patterns formed by stars, but the distinguishing feature of the two bright pointers alpha and beta Centauri make Crux unmistakable.
Crux lies in a dense and brilliant part of the Milky Way, which makes the famous dark nebula known as the Coalsack striking in silhouette against the star background.
This is the head of the Emu to the native aborigines of Australia. The rest of the Emu is made from the dark lanes in the Milky Way.
Alpha Crucis was too far south to have been given an ancient name so Acrux is simply a combination of the A in alpha and Crux. Being of first magnitude (0.83), it is the 12th brightest star in the sky and 321 light years distant from us. Under high power, a telescope reveals it to be a binary system with two very similar B type stars having magnitudes of 1.33 and 1.73 separated by 4 arc seconds. With surface temperatures of around 27,000K they are highly luminous, the brightest 25,000 time more luminous than our Sun. In fact, the brighter star is itself a double, the two component stars orbit each other every 76 days but are too close to split with a telescope. So Acrux is a triple star system. A further, type B4, star lies 90 arc seconds away and may belong to the system as well. It has a similar proper motion - that is, its direction of motion through space - but is probably a more distant star that just happens to lie in the same direction.
NGC 4755 (k, kappa Crucis) is an open cluster of stars, that contains about 100 stars and is about 10 million years old. It lies some 7500 light years away and spans a 10 arc minutes field of view so filling a volume of space about 20 light years across. Lying close to Beta Crucis, it is easy to find and best seen with binoculars or a telescope at low power. It contains many highly luminous blue-white stars along with a central red supergiant that makes a beautiful colour contrast. It was named the Jewel box by Sir John Herschel who called it a "casket of variously coloured precious stones". It can easily be seen by the unaided eye as a star, and indeed was originally catalogued as such in pre-telescope times.
The three day crescent Moon will be very close to Venus and Saturn on viewing night, with Jupiter risen in the east.

Sunday, 20th May, 7.30 at Pedro Castle.

CAYMAN ISLANDS ASTRONOMICAL SOCIETY
NEWSLETTER MAY 2007
The next viewing session will be on Sunday, 20th May, 7.30 at Pedro Castle.
Checkout our website: http://caymanastronews.blogspot.com/.

Saturday, the night before our viewing, look out for the moon and Venus, which will be very near each other, with the moon in a waxing crescent phase.
Jupiter – the king of the planets – will be rising in the east at meeting time. Jupiter is the fourth brightest object to light up the heavens, after the sun, moon, and Venus.
Saturn remains in Leo during May and will continue to form a small quadrilateral with Regulus and two other stars of the constellation.
The constellation illustrated above is Corvus, the Crow or Raven, a very noticeable skewed box that crosses the sky just to the west of first magnitude Spica in Virgo. It has only 11 stars visible to the naked eye (brighter than magnitude 5.5), and can easily be seen in our southern sky. It was one of the 48 constellations listed by Ptolemy, and also counts among the 88 modern constellations.
Although Corvus contains no Messier objects, you can see two objects labeled “NGC” on the picture.
The New General Catalogue (NGC) is the best-known catalogue of deep sky objects in amateur astronomy. It contains nearly 8,000 objects, known as the NGC objects. The NGC is one of the largest comprehensive catalogues, as it includes all types of deep sky objects (not specialised to just galaxies for instance).
The catalogue was compiled in the 1880s by J. L. E. Dreyer using observations mostly from William Herschel, and then subsequently expanded with two Index Catalogues (IC I & IC II), adding nearly 5,000 objects.
NGC 4361 is a Planetary nebula. The nebula itself resembles a small elliptical galaxy, but the magnitude 13 center star gives away its true nature.
A planetary nebula is an astronomical object consisting of a glowing shell of gas and plasma formed by certain types of stars at the end of their lives.
They are in fact unrelated to planets; the name originates from a supposed similarity in appearance to giant planets. They are a relatively short-lived phenomenon, lasting a few tens of thousands of years, compared to a typical stellar lifetime of several billion years. About 1,500 are known to exist in the Milky Way Galaxy.
NGC 4038/NGC 4039 are known as the Antennae Galaxies) are a pair of interacting galaxies. They were both discovered by Friedrich Wilhelm Herschel in 1785.
As the two galaxies interact, billions of stars are born, mostly in groups and clusters of stars. The brightest and most compact of these are called super star clusters.
Recent observations show that only about 10% of the newly formed super star clusters in the Antennae will live to see their ten millionth birthday. The vast majority of the super star clusters formed during this interaction will disperse, with the individual stars becoming part of the smooth background of the galaxy. It is however believed that about a hundred of the most massive clusters will survive to form regular globular clusters, similar to the globular clusters found in our own Milky Way galaxy.
The two spiral galaxies started to merge together about 500 million years ago making the Antennae galaxies the nearest (at 63 million light years) and youngest example of a pair of colliding galaxies.
Within 400 million years, the Antennae's nuclei will collide and become a single core with stars, gas, and dust around it. Observations and simulations of colliding galaxies suggest that the Antennae Galaxies will eventually form an elliptical galaxy.
The Antennae galaxies take their name from the long antenna-like arms extending far out from the nuclei of the two galaxies, best seen by ground-based telescopes. These tidal tails were formed during the initial encounter of the galaxies some 500 million years ago. They give us a preview of what may happen when our Milky Way galaxy collides with the neighbouring Andromeda Galaxy about 6 billion years from now.
Clear skies
Nick (9256576, 9473065, 9492557)

Thursday 19th April Pedros Castle

CAYMAN ISLANDS ASTRONOMICAL SOCIETY

We will aim to meet on Thursday, 19th April at 7.30 at Pedro Castle. Our rule of thumb is that if the skies are more than 50% cloudy, we cancel. This can sometimes be a difficult decision. Call me if in doubt. (925 6576 cell, 947 3065 home, 949 2557 work)

As of next month, for all paid-up members, we will be offering an extra session a month. It may be themed around a particular event, or it may just be an extra viewing. It will probably be at short notice, and I will contact everybody via email.
The membership form is below.

This month’s newsletter has been put together by Chris Cooke

April Highlights

Following the spectacular Lunar Eclipse seen at Moonrise on March 3rd last month I thought Id take as a theme for this month the Moon, especially as it has a number of additional celestial tricks to perform this month. The dates listed below are in chronological order finishing with some observing highlights for the meeting on the 19th

A Full Moon on 2nd April

A Full Moon with quite some significance! The Moon is at its apogee – that is it’s at its furthest from the Earth at 400,000 kilometers .The disk as seen from the Earth is therefore at its smallest. Everyone throughout the world will see a full looking moon this night but in fact no one will see the disk when it’s actually full. On the 2nd the Moon is just past full when it rises in the East at Dusk. This is the first full moon since the Spring Equinox and is actually called the Paschal Full Moon. The Spring Equinox marks the point where the Sun crosses the Equator - night and day at this moment are of equal length and it signifies the beginning of spring in the Northern Hemisphere. Easter falls on the first Sunday after the Paschal Full Moon, so that’s why Easter is on the 9th April this year!

A New Moon on 17th April

On April 17th an extremely young thin Crescent Moon will be visible close to the horizon and just after sunset on the Western Coast of America. It will not be until the following evening that the Moon will be visible from the Caymans

Astronomical Society Meeting on 19th April

Visible in early evening over the Western Horizon is quite a visual spectacle! The 2 day old Moon will form a triangle with the brilliant planet Venus and the star aptly named as the Red Eye of Taurus the Bull - this is in fact a red giant called Aldebaran .

Also above the Moon will be a bright group of stars called the Pleiades. This is an Open Cluster of young bright blue stars and is called various names, M45 or the Seven Sisters as well as the Maia Nebula

However the Moon will steal the show. Here is a map for a 3 day old showing some of the more obvious features. In a telescope the image may appear upside down and even reversed left to right! (It depends on the type of telescope used).

On the other side of the sky will be Saturn and through the 8 inch Society Telescope the rings will be seen as well as cloud bands on the planet’s gaseous surface. To keep up the monthly theme up to 5 of Saturn’s Moons should be visible


The Lyrid meteor shower (April 16 – 25) deserves a mention too. The radiant or the point in the sky where the meteors appear to come from will not rise until after midnight. The shower peaks this year on April 22 giving around 20 per hour at the maximum. – But you never know, we may be lucky!!

Finally a Blue Moon on 31st May

A final trick for next month! The definition of a Blue Moon is two full moons in a month – not really blue at all but something to talk about !!

Thursday 22nd March Pedros Castle

Cayman Astronomical Society Newsletter for March 2007
(courtesy George Dalsheimer)

There is a Lunar Eclipse on March 3rd.

Our viewing is scheduled for March 22 at Pedro Castle.Time 7.00 pm

Daylight Savings Time in the US begins March 11, 2007

The Vernal Equinox occurs on March 21st (Astronomy Magazine has it on March 20th – not sure why). The spring equinox is the time when the sun rises directly in the east and sets directly in the west for everyone on earth. In other words the Sun is directly over the equator. The word equinox means equal night but in fact the length of the day is actually longer than the length of night. This is because light from the sun can be seen before it rises and after it sets. Equality actually occurs several days before March 21st. Because of the location of objects in the sky at this time, it is possible to view all of the Messier Objects in one evening; of course you have to stay up all night. More about this later.

There will be many objects that can be viewed and below is a short list of some of the more obvious ones.
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Moon – a sliver to the west.
Venus – close to the moon.
Andromeda Galaxy – setting and close to Venus (M31) Galaxy
Pleiades or Seven Sister. (M45) open cluster in Taurus

More overhead
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Orion and Orion’s Belt Orion’s Nebulae (M 42) Nebula
Rigel
Betelgeuse
Sirius
Saturn
Beehive Cluster (M 44) an open cluster of stars in Cancer

To the east
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Arcturus
Spica
Whirlpool Galaxy (M 51)


The M numbers above refer to the Messier Catalogue and his numbering system. The March issue of Astronomy Magazine has a pull out section devoted to Messier. Charles Messier (1730-1817) was a French astronomer whose main interest was comets. However, he noted “cloudy” areas of the sky that did not move the way comets do. He began to make notes about these objects in 1758 and before he died he had listed 109 objects that are now called Messier Objects and numbered 1 to 109.

Some of the objects can be seen as smudges with the naked eye on a clear night. People with good eyesight can usually spot at least 20. Most of the objects can be seen with a good pair of binoculars. In fact some Messier objects, are best viewed through binoculars. As noted above, during the later part of March a good viewer can see all of the Messier Objects in one night. Astronomy clubs around the globe have Messier Parties to see how many objects they can see.

What are Messier Objects? To be continued.

Tuesday 20th February Viewing – Pedro Castle

The official viewing session starts at 7 p.m. with Venus and the thin crescent moon low in the western sky. Mercury should be visible at the time of writing (except it is cloudy) but will be gone by the 20th. See note below. The planet Saturn (a favourite of viewers) should be easily visible in the eastern sky, and we will be taking a good look.
Orion will still dominate naked-eye viewing and both binoculars and telescopes will give good views of the Orion Nebula and the Andromeda Galaxy. As usual we will also look out for any other objects of interest, such as satellites etc.
P.S.
Members with telescopes may also want to see two difficult planets on the date below. (Information from the Sky and Telescope website) – Richard McLeod
· Wednesday, February 7
· Mercury is at greatest elongation, 18° east of the Sun. A telescope shows that Mercury's tiny disk (shimmering and fuzzing through the low-altitude air) is half lit, compared to Venus's gibbous phase.
· A telescopic challenge: Uranus, 6th magnitude, is about ¾° to the right (celestial northwest) of dazzling Venus at the time of late twilight for North America. Assuming you can see it at all, you may need a star atlas to distinguish Uranus from surrounding stars. For instance, 4th-magnitude Lambda Aquarii is farther to the two planets' lower right; try for this first.

Februarys Meeting

Unofficially the date of Tuesday Feb 20th has been set at Pedros Castle

Contact Nick Kelly (kellys_n@candw.ky) for more details