Rome Star Gazers

This globular cluster is nicely positioned about 5º south of the tail portion of the small constellation Delphinus, the Dolphin, (del-FIE-nus).     Being so small you might expect that there aren’t any deep sky objects to look at within Delphinus, but this small, 9th-magnitude, globular cluster about 2 minutes in diameter, is visible through a small telescope.  Some have reported seeing it with just a pair of binoculars.  This globular cluster is located about 54,000 light years from Earth.
The constellation that this cluster is in will fit within the field of view of your pair of binoculars.  To some, this constellation looks more like a small kite with a short tail draping generally toward the south. I have even had some friends confuse this small constellation with the Little Dipper.

This constellation has an interesting history that goes with the names of its two brightest stars: Alpha Delphini (Sualocin) and Beta Delphini (Rotanev).  These names were first published in 1814 by the Palermo Observatory guide.  It was originally thought that both names had no meaning.  That is, until much later when someone noticed that the letters of the star names reversed spelled the Latinized from of the name Nicolaus Venator, the assistant to the director of the Palermo Observatory! It turns out that the director of the Palermo Observatory bestowed the honor of naming the two stars after his assistant.

It is also interesting to note that there are only three stars named after modern time persons.  The two already mentioned and Cor Caroli (Alpha Canum Venaticorum) which was named after King Charles II of England.

While in this area of the sky, you might want to pan northward and look at the objects in Sagitta as well.

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One of my favorite objects in the sky is the Summer Triangle.  For me it symbolizes the coming of cooler weather and clearer skies and it has been slowly rising in the early evening skies over the past several months.  Now is the prime time to enjoy this beautiful asterism made up of Deneb, in Cygnus, Altair, in Aquila, and Vega, in Lyra.
There are plenty of objects within it boundary, including the constellation Sagitta.   Appropriately, Sagitta is Latin for “Arrow.”  Even though this is the third smallest constellation (only Equuleus and Crux are smaller) it has been recognized since classical times.

One reason for it being so well recognized is because it can be seen from both hemispheres due to it proximity to the celestial equator.

Seemingly unusual for many constellations, this one looks just like what it is called, an arrow.  During classical times it represented many arrows.  It is the arrow that Hercules used to kill the eagle that Zeus sent to punish Prometheus, it is also the arrow shot by Heracles at the Stymphalian Birds, it is the one which Apollo used to slay the Cyclops, and it is said to represent Cupid’s arrow.

While, because of its size, there are not many deep sky objects within Sagitta’s boundary there is one beautiful globular cluster right in its center that can be seen with a pair of binoculars, M71.  This globular cluster is about 13,000 light years distant, and is a little more than 7 minutes of arc in diameter (not quite as large or as bright as the famous Hercules cluster).

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This is a beautiful open cluster which lies over 9,000 light-years from the Sun.  It goes by names: the Owl Cluster, Kachina Doll Cluster, or the ET Cluster, due to its resemblance to the movie character.

To locate this cluster look 2° SSW of  Cassiopeiae.  It is fairly easy to spot because of its magnitude 6.2.  It is also nicely positioned so you will not have to strain your neck to keep it in view.

When you see it, you will know why it is called the dragonfly cluster.  The stars are very distinct and you will want to spend some time pouring over the stars within this open cluster.  Take your time and enjoy this celestial treasure.

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If you enjoy seeing something strikingly different in the night sky, you should take a look at the beautiful colors of the double star, Albireo, in Cygnus.   The gold and blue colors are vivid through a pair of binoculars or a telescope.

Albireo: A Bright and Beautiful Double

Normally, I have a little difficult picking out star colors.  Folks will say, “Hey, look at that yellow star over there,” or, “Wow, look at that red star.”  Well, they all look pretty much white to me.  That is, the vast majority of them do.  Now, Albireo is a wonderful exception to the rule.  The colors are very easy to spot, even for these tired old eyes.

To spot Albireo you first must locate Cygnus, the Swan.  It is sometimes also called the Northern Cross.  After the skies get good and dark, look directly overhead for the Summer Triangle.  The base of the triangle will be to the north.  The eastern star of the base is Deneb, the brightest star in Cygnus.  The body of the swan is composed of four fairly bright stars that track to the southwest from Deneb.  From Deneb the second bright star is the central cross star or the breast of the swan.  Continuing southwest two more stars in a stepping stone fashion you will come up on Albireo.

To the naked eye Albireo appears to be a single star but through a pair of binoculars you can easily see it to be a double star.  There is question as to whether it is an optical double or a true binary pair, although the literature reports that they are 386 l.y. from Earth, possible suggesting that they are actually in close proximity to each other.  In any case, this pair of stars is among the prettiest in the heavens.  To my way of thinking, as far as color, you will not find any better.

While you are in the area, you might want to scan the sky for other treasures.  This is an area of the sky that is rich in deep sky objects because it lies along the galactic plane and you are looking into the Milky Way.

On a side note, if you wish to see the color of stars and you, like me, find it difficult.  Try this trick: while looking at the star through your binoculars or telescope, slowly defocus the instrument.  As the star begins to blur, the color is enhanced, making the color easier to see.

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This year, August 12 will mark the annual maximum of the Perseid meteor shower.  At its peak, if the skies are clear and dark, we can see up to 80 meteors or ‘shooting stars’ per hour. Meteors are the result of small particles entering the Earth’s atmosphere at high speed and burning up.  In the case of the Perseid shower these come from the tail of Comet Swift-Tuttle, which was last passed Earth’s orbit 1992.  The 1993 Perseid meteor shower was spectacular!

The reason it is called the Perseid meteor shower is because, to the eye, the meteors appear to originate from a central point or ‘radiant’ in the constellation of Perseus.

Although the Perseids peak on the 12th August, the shower can be seen for some time either side of that date and it is worth looking out for them the night before and the night after the 12th.  To see the meteor shower, look towards the north-eastern sky from 2200 British Summer TIme (BST) onwards. In clear weather and away from the light pollution of major cities, it should be possible to see a meteor at least every few minutes, with most appearing as brief streaks of light. The waxing gibbous Moon will be in the evening sky but will have set by 0130 BST on the morning of the maximum so its light will not interfere with the view after that time.

Perhaps best of all, and unlike many astronomical phenomena, meteors are best seen with the unaided eye, rather than through a telescope or binoculars and are perfectly safe to watch.

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The Southern Delta Aquarid meteor shower peaks on Monday, July 27th, although you can view these meteors all week long.  This meteor shower has two branches (northern and southern components) that peak at different times.  The southern branch or component is the most active of the two with a zenithal hourly rate (ZHR) of around 20 meteors per hour.  This is under ideal conditions with the “radiant” at the zenith under very dark skies.

It is a good week for the shower’s peak because the Moon will be First Quarter.  This means that the early morning viewing of this shower will be unhampered by the Moon’s glare.   The one promising thing about the Southern Delta Aquarid meteor shower is, it represents the preamble to the famous August Perseid meteor shower (one of the best showers of the year).  We will be discussing the Perseid shower in the next issue or two.

If you wish to observe a Southern Delta Quarid meteor, your best bet is to get out early in the morning, before sunrise, and observe while you are facing in a southerly direction.  These meteors tend to be very faint so you will need to be in a fairly dark location while observing.
You do not need a telescope or pair of binoculars when observing meteors but in this case you might want to bring one along so you can do some deep sky observing as you look for meteors.

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One of my favorite type of objects is a globular cluster.  There is something about looking at a large ball of stars and imagining just the shear numbers and distances from us that captivates my mind.   It also is a pretty sight to behold through a pair of binoculars or small telescope.

This week we have three beautiful globular clusters to view along our meridian around 9:00 p.m. EDT.  The first is M13, the Great Hercules Cluster.  I guess this is my favorite because I discovered it by panning the sky.  Afterward I learned what it was.  To locate this object, find Hercules and look in the middle of the western edge of the keystone.  It is easily seen through a pair of binoculars as a large cloudy ball (large is a relative term).  By its size and appearance, it is clearly not a star or a planet.

M13: The Great Globular Cluster in Hercules

The next two globular clusters are in the southern sky, in Scorpius: M4 and M80.   Many like M4 more than M13 but that is a matter of preference.  To find M4, look for the brightest star in Scorpius, Antares.  It is a nice red star so you should be able to find it nicely.  M4 is just 1 degree to the west of Antares.  You will need to look at it through a pair of binoculars to see it.

Hubble Space Telescope Finds Stellar Graveyard in M4

M80 is a little smaller than M4.  To find this one, look north-northwest of M4 by about 5 degrees.  You will also need a pair of binoculars to view this one.

Hubble Images a Swarm of Ancient Stars in M80

Although M4 appears larger and brighter than M80, in reality it is 4.5 times farther away than M4 so M80 is actually larger and brighter than it.

These three globular clusters are fairly easy to locate and observe.  Go out on a nice clear night and view these wonders.   They will capture your imagination.

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Ophiuchus is one of the 88 contemporary constellations, and was also one of the 48 listed by Ptolemy. It is interesting to note that of the 13 zodiacal constellations (constellations that contain the Sun during the course of the year), Ophiuchus is the only one which is not counted as an astrological sign.  Ophiuchus is depicted as a man supporting a serpent.  His body is superimposed on the snake and divides it into two parts, Serpens Caput and Serpens Cauda.

Ophiuchus

One of the common legends reports that the figure represents the legendary physician Asclepius.  Asclepius learned the secrets of life and death from one serpent bringing another some herbs which healed it.

As it happens, Asclepius had previously tried to kill it. In order to avoid the human race becoming immortal under Asclepius’ care, Zeus eventually killed him with a bolt of lightning and placed him in the heavens to honor his good works. There is common reference to Chiron (an intelligent, civilized and kind centaur) in legend.  This is the case because of the presence of the constellation Sagittarius, which was in later times occasionally considered to represent Chiron.

The brightest stars in Ophiuchus include α Ophiuchi, called Rasalhague, at the figure’s head; and λ Ophiuchi, a triple star, at his elbow.
Ophiuchus contains several globular clusters, such as M9, M10, M12, M14, M19, M62, and M107.  The unusual double galaxy known as the Starfish Galaxy (NGC 6240) is also found in Ophiuchus although not easily seen through moderate-sized backyard telescopes.

NGC 6240

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Antares is the brightest star in Scorpius.  It is located low on the meridian around 9:00 p.m. this week.  I have selected this star as our celestial feature of the week because it has some very interesting qualities, especially when compared to the star we are most familiar; the Sun.

The Dark River to Antares

Antares is a red supergiant star in the Milky Way galaxy.  It is the sixteenth brightest star in the night sky.  It has a magnitude which varies because of a small partner star, from +0.9 to + 1.8.
This star has a diameter that is about 800 times larger than the diameter of the sun.  This means that 64 million suns can fit in Antares!  To give you a perspective, remember that 166,000 Earths can fit into the Sun!  That means that 10.6 trillion Earths can fit in Antares!  Antares is about 600 light-years from us and it is estimated that it gives off 10,000 times more light than the sun.
Antares got its name from the Ancient Greek word meaning “holds against Mars.”  This is because Antares looks a lot like Mars, they both have an amber hue.  Other ancient Arabic lore says that Antares is the warrior-poet star.

I hope you take time to locate Scorpius and the brightest star, Antares.  Add this celestial wonder to your list of objects.  Good hunting…..

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Jupiter is the fifth planet from the Sun and by far the largest. It is more than twice as massive as all the other planets combined (the mass of Jupiter is 318 times that of Earth).

The Ring of Jupiter

The planet is the fourth brightest object in the sky (after the Sun, the Moon and Venus), partly because of its size and its reflective gaseous atmosphere. It has been known since prehistoric times as a bright “wandering star”. But in 1610 when Galileo first pointed a telescope at the sky he discovered Jupiter’s four large moons Io, Europa, Ganymede and Callisto (now known as the Galilean moons) and recorded their motions back and forth around Jupiter. This was the first discovery of a center of motion not apparently centered on the Earth. It was a major point in favor of Copernicus’s heliocentric theory of the motions of the planets (along with other new evidence from his telescope: the phases of Venus and the mountains on the Moon).
Jupiter was first visited by Pioneer 10 in 1973 and later by Pioneer 11, Voyager 1, Voyager 2 and Ulysses. The spacecraft Galileo orbited Jupiter for eight years. It is still regularly observed by the Hubble Space Telescope.

This gas giant is about 90% hydrogen and 10% helium (by numbers of atoms, 75/25% by mass) with traces of methane, water, ammonia and “rock”. This is very close to the composition of the primordial Solar Nebula from which the entire solar system was formed. Saturn has a similar composition, but Uranus and Neptune have much less hydrogen and helium.  Jupiter probably has a core of rocky material amounting to something like 10 to 15 Earth-masses.  Above the core lies the main bulk of the planet in the form of liquid metallic hydrogen.
At last count, Jupiter has 63 known satellites: the four large Galilean moons plus many more small ones some of which have not yet been named.  Io, Europa and Ganymede are gravitationally locked together in a 1:2:4 orbital resonance and their orbits evolve together. Callisto is almost part of this as well. In a few hundred million years, Callisto will be locked in too, orbiting at exactly twice the period of Ganymede (eight times the period of Io).

Jupiter's Family

Jupiter (a.k.a. Jove; Greek Zeus) was the King of the Gods, the ruler of Olympus and the patron of the Roman state. Zeus was the son of Cronus (Saturn).  Jupiter’s satellites are named for other figures in the life of Zeus (mostly his numerous lovers).
We can see Jupiter in the late night in that it rises above the eastern horizon around 11 p.m. EDT.  It is easy to spot and you can see its four Galilean moons and equatorial cloud belts with just a pair of binoculars.

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