Author: Tammy Plotner

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“A drop fell on the apple tree, Another on the roof; A half a dozen kissed the eaves, And made the gables laugh. A few went out to help the brook, That went to help the sea. Myself conjectured, Were they pearls, What necklaces could be!” As you drink in the words of Emily Dickinson, get ready for two showers of another type this week: meteor showers.

Beginning this evening, July 27, the Delta Aquarid meteor shower will peak with an average of 25 “shooting stars” per hour for maximum activity with many of them leaving yellowish trails. While there is no specific parent comet for the shower, many believe they are the product of periodic Comet 96P/Machholz 2 – which disintegrated in 1994. Will this cause the activity to be stronger or not? No one really knows for sure. Fall rate activity is always dictated by the precise moment the Earth turns into the meteoroid stream and no specific location or time can ever be precise.

But don’t be discouraged if it’s cloudy tonight. This whole week will be a grand time to watch for meteors as the Capricornid meteor shower peaks on July 29. This time we’re looking at about 15 to 20 meteors per hour, but a shower that also has a reputation for bolides. Who among us doesn’t get a thrill at watching a bright fireball pass overhead!

“Dazzling and clear shooting over our heads, A moment, a moment long it sail’d its balls of unearthly light over our heads, Then departed, dropt in the night, and was gone.”

Numerous astronomers have tried to identify the object responsible for the formation of the Alpha Capricornid stream, but no definitive parent has ever really been chosen because the stream is so broad. It may be Denning-Fujikawa, or it could be Honda-Mrkos-Pajdusakova, but I like to think it might be possible that Apollo asteroid Adonis is the case. Although there is radio evidence to support that, I still find something dreadfully romantic about spending an evening watching for meteors and what more romantic figure than Adonis?

“As I flit through you hastily, soon to fall and be gone, what is this chant, What am I myself but one of your meteors?” Over time, meteor showers have inspired poets and artist alike, just like these words from Walt Whitman. How long has it been since you read a poem, or contemplated the evening sky? With the Moon far gone from the early evening, why not take children or grandchildren out with you? Let them catch fireflies in a jar, like captured meteors to take their fancy. Try the words of May Justus: “One night a little firefly, Was looking at a star, And said – but no one heard him – “I wonder what you are.” Then, eager for adventure, And brave as he could be, He trimmed his little lantern, And flew away to see!”

Even if you don’t take such fanciful notions to viewing a meteor shower, there’s still no harm enjoying a pleasant summer evening outdoors and adding to your scientific studies. For the most part, activity will take place in the south/southeast, so face in that general direction. As always, around midnight is a preferable time to begin – but there could always be early arrivals. Make your evening comfortable by bringing a blanket to lay on, or a reclining chair. Little things like a thermos of lemonade, cookies, insect repellent and binoculars are always welcome. If you live near city lights, why not make it a special event and take a drive to the countryside? And take along the words of Melville: “Of thee we think, in a ring we link; To the shearer of ocean’s fleece we drink, And the Meteor rolling home.”

[/caption]Greetings, fellow SkyWatchers! Now that the Moon is gone from the early evening skies and I’m back from that soul vacation, tracing my way across the constellations it’s time to break out binoculars and telescopes and enjoy some of the summer’s finest globular clusters – both easy and challenging. For everyone, it’s also time to get back in our atmosphere with drops of Jupiter in our hair and check out the Mighty Jove as it smokes up the sky. Are you ready to dance?

Friday, July 25 – Today in 1971, Apollo 15 was launched on its way to the Moon, and tonight we’ll launch our way north to the Mighty Hercules for a look at another globular study – M92. Although in a relatively open field for starhoppers, it’s not too hard to find if you can imagine it as the apex of a triangle with the northern keystone stars – Eta and Pi – as the base (RA 17 17 07 Dec +43 08 11).

At near magnitude 6, Class IV M92 was discovered by Johann Bode in 1777 and cataloged as Bode 76. Independently recovered by Messier in 1781 and resolved by Herschel in 1783, this bright, compact globular is around 26,700 light-years away and is about 12 to 14 billion years old. It contains 14 RR Lyrae variables among its 330,000 stars and also a very rare eclipsing binary. Viewable unaided under the right conditions and very impressive in even small binoculars, M92 is a true delight to even the smallest of telescopes. It has a very bright and unresolvable core with many outlying stars that are easily revealed. Larger scopes will appreciate its fiery appearance!

Now let’s hop south to Beta Ophiuchi to have a look at NGC 6426 about a fingerwidth south (RA 17 44 54 Dec +-3 10 12). There’s a very good reason why you’ll want to at least try with Herschel II.587. Discovered by Sir William in 1786, this 11th magnitude Class IX globular looks destroyed in comparison to M92. At 67,500 light-years away, it is more than twice the distance from us as M92! Residing 47,600 light-years from the galactic center, NGC 6426 contains 15 RR Lyrae variables (three of which are newly-discovered), and is the most metal-poor globular known. So what’s the relation to M92? It’s even a little bit older!

Forget about finding this one in binoculars and very small telescopes. For the mid-sized scope you’ll find it conveniently located about halfway between Beta and Gamma Ophiuchi – but it’s not easy. Faint and diffuse, a large telescope is required to begin resolution.

Saturday, July 26– For hardcore observers, tonight’s globular cluster study will require at least a mid-aperture telescope, because we’re staying up a bit later to go for a pair that can be seen in the same low power field – NGC 6522 and NGC 6528. You will find them easily at low power just a breath northwest of Gamma Sagittarii (Al Nasl), or the tip of the “teapot’s” spout. Once located, switch to higher power to keep the light of Gamma out of the field and let’s do some studying.

The brighter, and slightly larger, of the pair to the northeast is Class VI NGC 6522 (RA 18 03 34 Dec 30 02 02). Note its level of concentration compared to Class V NGC 6528 (RA 18 04 49 Dec 30 03 20). Both are located around 2,000 light-years from the galactic center, and are seen through a very special area of the sky known as “Baade’s Window” – one of the few areas toward our galaxy’s core region not obscured by dark dust. While they are similar in concentration, distance, etc., NGC 6522 has a slight amount of resolution toward its edges while NGC 6528 appears more random.

Both NGC 6522 and NGC 6528 were discovered by Sir William Herschel on the same night 1784 and both are the same distance from the galaxy’s nucleus. But there the similarities end: NGC 6522 has an intermediate metallicity. At its core, the red giants have been depleted – stripped tidally by evolving blue stragglers. It is possible that core collapse has already occurred. NGC 6528, however, contains one of the highest metal contents of any known globular cluster collected in its bulging core!

Now, let’s go kill our night vision and have a look at Jupiter! During the course of the evening of July 26-27, several events will happen – including eclipses and transits. For viewers in the United States eastern time zone, look for the Great Red Spot to appear on the meridian at around 10:48 p.m. While it’s difficult to make out the faint contrast of this most popular of all jovian features, take the opportunity to experiment with color filters if you have them. Even wearing sunglasses can sometimes produce surprising results!

Sunday, July 27 – Today in 1892, a very special astronomer was born – Sir George Biddell Airy. Does that name sound familiar? Anyone who uses a refractor understands the properties of the “Airy disc” as first outlined in his paper “On the Diffraction of an Object-Glass with Circular Aperture.” But, Sir George achieved a bit more: As Astronomer Royal from 1835 to 1881, his tireless devotion to planetary study led to the discovery by P. A. Hansen of two new irregularities in the moon’s motion. Not enough? Airy’s calculations also determined the mean density of the Earth. More? Then thank Sir George for giving us Greenwich Mean Time!

Are you still having no luck in finding a deep-space object? Then how about one that’s simple to locate for all optics. All you have to know is Antares and go west…

As one of the loosest globular clusters, M4 would be tremendous if we were not looking at it through a heavy cloud of interstellar dust. To binoculars, it is easy to pick out a very round, diffuse patch – yet it will begin resolution with even a small telescope. Large telescopes will also easily see a central “bar” of stellar concentration across M4’s core region, which was first noted by Herschel.

As an object of scientific study, the first millisecond pulsar was discovered within M4 in 1987 – one which spins 10 times faster than the Crab Nebula pulsar. Photographed by the Hubble Space Telescope in 1995, M4 was found to contain white dwarf stars – the oldest in our galaxy – with a planet orbiting one of them! A little more than twice the size of Jupiter, this planet is believed to be as old as the cluster itself. At 13 billion years, it would be three times the age of the Sol system!

Have a great weekend….

As the summer nights in the northern hemisphere grow short, Saturn fades quickly to the west and with it takes our great views of the solar system’s most serene and restful planet. If you were to walk out tonight and point a small telescope Saturn’s way, what would you see? Step right up the the StarGazer’s Telescope and let’s look…

Saturn, the sixth planet from the Sun, has the most spectacular set of rings in the solar system – ones which are easily seen in even the smallest of telescopes. Even at roughly 793 million miles away, we can still see this thin band of icy particles and rubble circling the magnificent planet. Maybe it was a comet that ventured too close… Perhaps Saturn’s moons collided… But no matter what the explanation is, the gentle yellow serenity of Saturn is something to behold.

Can you see Saturn’s gentle, yellow color? Much of the atmosphere of Saturn is made of hydrogen and helium, but there is also water vapor, methane, ammonia, and nitrogen. While it looks warm by nature, these cloudtops are quite cold, about –220° Fahrenheit. Winds in the upper atmosphere reach 500 meters (1,600 feet) per second in the equatorial region which is about five times faster than any hurricane force wind ever encountered here on Earth. These super-fast winds, combined with heat rising from within the planet’s interior, cause the yellow and gold bands visible in the atmosphere.

Did you know Saturn was the most distant of the five planets known to the ancients? In 1610, Galileo Galilei was the first to gaze at Saturn through a telescope and his view wasn’t even as close to as good as what we see here. In 1659, Christiaan Huygens, used a far more powerful telescope and announced that Saturn was surrounded by a thin, flat ring. A few years later in 1675, Jean-Dominique Cassini discovered a ‘division’ between what are now called the A and B rings. Thanks to modern science, we now know the gravitational influence of Saturn’s moon Mimas is what’s responsible for the black band known as Cassini Division. Can you see it peeking in and out when the atmosphere gets steady? Even from all these millions of miles away, we’re still able to resolve a feature which is 4,800 kilometers (3,000 miles) wide.

Do you want a real rush? While you’re looking at Saturn, click here. This is an audio file of radio emissions from Saturn. The Cassini spacecraft began detecting these radio emissions in April 2002, when Cassini was 374 million kilometers (234 million miles) from the planet, using the Cassini radio and plasma wave science instrument. Isn’t it creepy? It’s also kind of beautiful too… Like listening to whale songs.

Now move over… It’s my turn at the eyepiece.

Greetings, fellow SkyWatchers! Our weekend begins with one very hot look at a very cool area of the Moon – the lunar poles. Why is finding ice just so important? Hang on to your eyepiece because we’ll continue this lunar expedition with some mountain climbing and a look at the big lunar picture. Before our weekend is out, we’ll take a trip to the land of Yed and find out what’s coming up on Monday night. Time to slip into the night… Together.

Friday, July 11 – Tonight let’s take look at the lunar poles by returning to an old previous study crater, Plato. North of Plato you will see a long horizontal area of grey floor – Mare Frigoris – the “Cold Sea.” North of it you will note a “double crater.” This elongated diamond-shape is Goldschmidt, and the crater which cuts across its western border is Anaxagoras. The lunar north pole isn’t far from Goldschmidt, and since Anaxagoras is just about one degree outside of the Moon’s theoretical “arctic” area, the lunar sunrise will never go high enough to clear the southernmost rim. As proposed with yesterday’s study, this “permanent darkness” must mean there is ice! For that very reason, NASA’s Lunar Prospector probe was sent to explore here. Did it find what it was looking for? Answer – Yes!

The probe discovered vast quantities of cometary ice which has hidden inside the crater’s depths untouched for millions of years. If this sounds rather boring to you, then realize this type of resource may aid our plans to eventually establish a manned base on the lunar surface!

On March 5, 1998 NASA announced that Lunar Prospector’s neutron spectrometer data showed water-based ice was discovered at both lunar poles. The first results showed the “ice” mixed in with lunar regolith (soil, rocks and dust), but long-term data confirmed nearly pure pockets hidden beneath about 40 centimeters of surface material – with the results being strongest in the northern polar region. It is estimated there may be as much as 6 trillion kilograms (6.6 billion tons) of this valuable resource! If this still doesn’t get your motor running, then realize that without it we could never establish a manned lunar base because of the tremendous expense involved in transporting our most basic human need – water.

The presence of lunar water could also mean a source of oxygen, another vital material we need to survive. In order to return home or voyage onward, these same deposits could provide hydrogen which could be used as rocket fuel. So as you view Anaxagoras tonight, realize you may be viewing one of mankind’s future “homes” on a distant world!

Saturday, July 12 – Tonight let’s take an entirely different view of the Moon as we do a little “mountain climbing!” The most outstanding feature on the visible surface will be the emerging Copernicus, but since we’ve delved into the deepest areas of the lunar surface, why not climb to some of its peaks?

Using Copernicus as our guide, to the north and northwest of this ancient crater lie the Carpathian Mountains ringing the southern edge of Mare Imbrium. As you can see, they begin well east of the terminator, but look into the shadow! Extending some 40 kilometers beyond the line of daylight, you will continue to see bright peaks – some of which reach a height of 2072 meters. When the area is fully revealed tomorrow, you will see the Carpathian Mountains disappear into the lava flow that once formed them.

Continuing onward to Plato, which sits on the northern shore of Imbrium, we will look for the disjointed line of (1) Montes Recta – the “Straight Range.” Further east you will find the scattered peaks of (2) the Teneriffe Mountains. It is possible these are the remnants of much taller summits of a once stronger range, but only around 1890 meters of them still survive above the surface.

To the southeast, (3) Mons Pico stands like a monument 2400 meters above the grey sands – a height which places it level with Kindersley Summit at Kootenay Park in British Columbia. Further southeast is the peak of (6) Mons Piton – also standing alone in the barren landscape of Imbrium. Perhaps once a member of the (5) Montes Alpes to the east, Piton still towers 2450 meters above the surface with a base 25 kilometers in diameter still remaining in the lava flow. Yet look closely at the lunar Alpes, for (4) Mons Blanc is 3600 meters high!

Just north of shallow Archimedes stand (7) the Montes Spitzbergen whose remaining expanse trails away for 60 kilometers on the southern edge of a rille which begins at the small punctuation of crater Kirch to the north. While they only extend 1500 meters above the surface, that’s still comparable with the outer Himalayans!

Sunday, July 13 – So what if it’s the 13th? If you’re not superstitious, but only having bad luck in finding lunar features – then how about if we take a look at one that’s incredibly easy to find? We’ll continue our lunar mountain climbing expedition and look at the “big picture” on the lunar surface.

Tonight all of Mare Imbrium is bathed in sunlight and we can truly see its shape. Appearing as a featureless ellipse bordered by mountain ranges, let’s identify them again. Starting at Plato and moving east to south to west you will find the Alps, the Caucasus, and the Apennines (where Apollo 15 landed) at the western edge of Palus Putredinus. Next come the Carpathian Mountains just north of Copernicus. Look at the form closely: doesn’t it appear that perhaps once upon a time an enormous impact created the entire area? This was the Imbrium impact: compare it to the younger Sinus Iridum. Ringed by the Juras Mountains, it may have also been formed by a much later and very similar impact.

And you thought they were just mountains…

Now let’s have a look with our eyes first at Delta Ophiuchi. Known as Yed Prior (“the hand”), look for its optical double Epsilon to the southeast, symmetrically named Yed Posterior. Try using binoculars or a telescope at absolute minimum power for another undiscovered gem…

Delta Ophiuchi is 170 light-years from us, while Epsilon is 108 – but look at the magnificent field they share. Stars of every spectral type are in an area of sky which could easily be covered by a small coin held at arm’s length. Enjoy this fantastic field – from the hot, blue youngsters to the old red giants!

Now, keep a watch out for a certain old, red giant named Antares on Monday night, June 14. For many of us, the Moon and the Rival of Mars are going to be hauntingly close – close enough to be an occultation event for some lucky observers!

Have a great weekend….

This week’s images are: Lunar North Pole – Credit: NASA, Lunar Mountain Peaks – Image Credit: Greg Konkel Annotations: Tammy Plotner, Half and Gibbous Moon – Credit: Roger Warner, and Delta Ophiuchi – Credit: Palomar Observatory courtesy of Caltech.