Category: What’s Up

The Moon, captured by Apollo 11 astronauts. Image credit: NASA. Click to enlarge.
Monday, September 12 – If you’re up before sunrise this morning, be sure to step outside with a pair of binoculars and check out how close Saturn is to the M44. You should be able to see them both in the same field of view!

Today in 1959, the USSR’s Luna 2 scored a mark as it became the first manmade object to hit the moon. The successful mission landed in the Paulus Putredinus area, and tonight we’ll go there.

The most outstanding feature will be mid-placed Copernicus. Head northeast for Eratosthenes caught on the “tail” of the Apennine Mountains. To the northeast you will see prominent crater Archimedes with smaller craters Aristillus and Autolycus to the east. South of this pair, and caught along the mountain range, you will spy a dark grey, heart-shaped area known as the “Rotten Swamp” – Paulus Putredinus. Apollo 15 landed near Mons Hadley on its northeastern shore, but Luna 2 beat it there. Look at the area between the southern Autolycus and Archimedes. Spaseba!

Before we call it a night, why not point your scope toward the star in the northeast corner of the diamond of Delphinus? Its name is Gamma and it is one of the best double stars in this area for a small optics. Discovered by Struve in 1880, this 100 light year distant pair will show a slight yellow tinge in the fourth magnitude primary, and perhaps a little green in the fifth magnitude secondary. Enjoy it tonight…

Tuesday, September 13 – Today in 1922, the highest air temperature ever recorded at the surface of the Earth occurred. The measurement was taken in Libya burned in at a blistering 136?F, but did you know that the temperatures in the sunlight on the Moon double that? Tonight let’s take a look at a sunlit feature as we head for the bright point of crater Euler.

Beginning towards the north in the mostly disclosed Mare Ibrium region, look for this small, but conspicuous crater near the terminator. Note that it is roughly the same size as its two attendant craters to the east – Lambert and Pytheas, but has a noticeably central peak. If timing is right, you may be able to see the peak of Mons Vinogradov peeking above the terminator to its west.

For viewers in New Zealand, you will have the opportunity to watch the Moon occult Tau Sagittarius on this universal date. Please check this IOTA webpage for details.

If that’s not “hot” enough for you, then take a look straight overhead at brilliant star Vega. It is a “Sirian type” star and with a surface temperature of about 9200 degrees Kelvin, it’s twice as hot as our own Sun. At around 27 light years away, our entire solar system is moving towards Vega at a speed of 12 miles per second, but don’t worry… It will takes us another 450,000 years to get there. If we were to arrive tonight, we’d find that Vega is around 3 times larger than Sol and that it also has a 10th magnitude companion that can often be resolved in mid-sized scopes. It’s one of the first stars to ever be photographed. Back in 1850, that simple star – Vega – took and exposure time of 100 seconds through a 15″ scope. How times have changed!

Wednesday, September 14 – If you have a clear western horizon, take the time after the Sun sets to look at how far the evening planets have now moved apart. With Venus still blazing, Jupiter is becoming harder and harder to spot as it has moved a handspan away to the west. It’s almost gone…

Before we head off into the night, let’s take a look at the lunar surface. While outstanding Gassendi will catch the eye, there are more craters along the shores of Mare Humorum that deserve some attention! South of Gassendi and along the west shore is Class III crater Mersenius. Perhaps the terminator will be dividing it at the time of your viewing at it will appear like a “bite” taken out of the edge. Perhaps it will be well lit and you will see a cruciform structure of mountains and craters. Tonight its features look quite high, but by tomorrow, it will be totally washed out.
Due south of Gassendi across Mare Humorum is Doppelmeyer, who’s eroded walls have left it nothing more than a ghost of its former self – yet you can still see an upsweep in its interior landscape. If skies are stable, power up and see if you can spot Rimae Doppelmeyer to the west or the faded ruins of Puiseux on its eastern flank.

Thursday, September 15 – Head’s up, Eastern Europe! Tonight you have a chance to watch the Moon occult Epsilon Capricornii. Please check this IOTA webpage for details in your area.

Tonight on the lunar surface, we’ll visit the far north as well look towards our guidepost, Sinus Iridum. Head north once again to spot the rather unusual rectangle shape of crater Babbage. This ancient, shallow enclosure has many younger craters within it, and Babbage A will be quite clear. Heading northeast about twice the length of Babbage, you will spot a rather deformed “heart shape” that marks crater Anaximander. This will be part of a group of five overlapping craters, and the name is given essentially to the whole complex. Look for younger crater Carpenter as a black ellipse with a bright border intruding in its walls.

While you’re out, stop to look up at Beta and Gamma Lyrae, the lower two stars in the “Harp”. Beta is actually a quick changing variable which drops to less than half the brightness of Gamma in around 12 days. For a few days the pair will seem of almost equal brightness and then you will notice the star closest to Vega fades away. Beta is one of the most unusual spectroscopic stars in the sky, and it is possible that its eclipsing binary companion may be the prototype of the “collapsar”, (yep. a “black hole”!) rather than a true luminous body.

Friday, September 16 -The Moon rises shortly before Sun sets tonight amidst the difficult to see stars of the constellation Aquarius. Believe it or not, Uranus is only about 3 degrees away, but it will be next to impossible to pick the distant planet out with the lunar glare. So why ignore the Moon? Let’s do some exploring and we can start just as easily as identifying the grey oval of Grimaldi.

Just north of Grimaldi is Class V Hevelius. It will show as a bright oval, similar to Grimaldi, but will contain an off-center mountain peak. Its north wall is broken by Class I Calaverius, a narrow, bright ellipse with a thin, black border to the east. Only 100 kilometers away from here on the edge of Oceanus Procellarum lay the remains of the very first successful lunar landing. It was here on February 3, 1966 that the Soviet probe – Luna 9 – touched down. The man-sized craft sent back panoramic television images to a waiting Earth, revealing the uneven, jagged surface covered with dust. So good were the probe’s images, that scientists were even able to discern small depressions and protrusions only millimeters in size.

Saturday, September 17 – On this day in 1789, Sir William Herschel discovered Saturn’s moon Mimas. And indeed the Moon will be on our mind as tonight is “Harvest Moon”.

At exactly 10:01 p.m. EDT, the Moon will become Full and it will be the closest to the Autumnal Equinox. Because the orbit is more horizontal with the eastern horizon, it will rise a dusk for the next several nights in a row. On the average, the Moon rises about 50 minutes later each night, but at this time of year it’s around 20 minutes later for mid-northern latitudes and even faster farther north. Because of this added extra light, the name “Harvest Moon” came about because it allowed farmers more time to work in the fields.

Often times we perceive the “Harvest Moon” as being more orange than any other time of the year. The reason is not only scientific enough – but true. Coloration is caused by the scattering of the light by particles in our atmosphere. When the Moon is low, like now, we get more of that scattering effect and it truly does appear more orange. The very act of harvesting itself produces more dust and often times that coloration will last the whole night through. And we all know the size is only an “illusion”…

So, instead of cursing the Moon for hiding the deep sky gems tonight, enjoy it for what it is… A wonderful natural phenomena that doesn’t even require a telescope! Is that Mars following behind it?

Sunday, September 18 – If you’re up before dawn this morning, why not take the opportunity to step outside and look at how much the sky has changed. The winter constellation of Orion has now well risen and the harbinger of the Winter – Sirius – has now appeared.

Once again, the Moon will play a major role in tonight’s sky, but why not take the time to enjoy some of its incredible features? With just your eye you can identify Mare Crisium to the northeast, and Mare Fecundatitus to the southeast. Mare Frigorus is the long, dark stretch that runs across the northern section and the expanse of Mare Ibrium and Oceanus Procellarum dominate the northwest quadrant. Can you spot the dark oval of Mare Humorum to the southwest or Nubium to its east?

Those of you with sharp eyes might be able to make out the small dark oval of crater Plato to the north or Grimaldi to the west. Can you see the bright point of Tycho? Just north of central is the very round, grey Mare Serenitatis and south of it, Mare Tranquillitatis. Using binoculars, trace out the bright rays of Proculus in the east and Tycho to the south. Aristarchus and Kepler shine like beacons in the northwest and while the southwest is far more muted, look for the bright point of Euclides.

Hang tough. A few more days and darker skies will be on our side! Until then? May all your journeys be at light speed…. ~Tammy Plotner

M17. Image credit: Hillary Mathis, N.A. Sharp, REU program/NOAO/AURA/NSF. Click to enlarge.
Monday, August 29 – Let’s begin our week by looking at a pair of planets that are moving apart. Just before dawn, have a look at how far Mercury and Saturn have now separated. In one week’s time they have drawn about how far apart as Jupiter and Venus were on the 22nd. Now, let’s wait until sunset as we see that Jupiter and Venus have now moved within 3 degrees of each other. The bright pair of planets make for a wonderful photographic opportunity, and tomorrow they will be much closer!

Tonight let’s celebrate dark skies by aiming our binoculars and telescopes about a fist’s width north of the top of the teapot’s lid – Kaus Borealis. The object of our interest tonight has many names, but let’s start by calling it M17.

Discovered twice within months in 1764 – first by Swiss astronomer de Cheseaux and then Charles Messier – this bright nebula is often referred to as the “Omega”, or “Swan” nebula. This huge area of nebulosity will appear almost like a comet in binoculars and take on the shape of the figure “2” for small telescopes. Upon closer scrutiny with larger aperture, the viewer will note the area inside the curve could possibly contain obscuring dark dust. At a dark sky location, or with the application of a filter, you can see many long filaments that radiate out from the central structure. Unlike previous study M8, the M17 does not contain any type of star cluster, although you can see many of them glittering in the folds of nebula. It is estimated that perhaps only 35 of these stars are actually associated with the “Swan” and the illuminating stars appear to be hidden within the brighter portions of the nebula itself. While estimates in distance are unclear, it is believed the M17 is about 5,700 light years from our own galaxy. It’s awesome!

Tuesday, August 30 – For a very large portion of the United States and Mexico, you will have the opportunity to watch the Moon occult bright star Upsilon Geminorum in the early morning hours. Please check this IOTA webpage for details on times and locations in your area. Clear skies!

If you were clouded out at sunset last night, look again at the western horizon as Venus and Jupiter have moved to just 2.2 degrees apart. Take a picture. Tomorrow they will be even closer.

Don’t put away your binoculars just because you think this next study is beyond you… Just lift your sights three degrees higher than the “Omega” and tonight we’ll fly with the “Eagle”.

Small binoculars will have no trouble distinguishing the cluster of stars discovered by de Cheseaux in 1746, but larger binoculars and small telescopes from a dark sky site will also see a faint nebulosity to the region that was reported by Messier in 1764. This “faint light” will remind you highly of the reflection that is seen within the Pleiades, or “Rosette” nebula. While the most outstanding views of the “Eagle” nebula are in photographs, larger telescopes will have no problem picking out a vague cloud of nebula, encased stars and an unusual dark obscuration in the center which has always reminded this author as a “Klingon Bird of Prey”. While all of this is very grand, what’s really interesting is the little notch on the northeast edge of the nebula. This is easily seen under good conditions with scopes as small as 8″ and is undeniable in larger aperture. This tiny “notch” rocketed to worldwide fame when viewed through the eyes of the Hubble. It’s name? “The Pillars of Creation”.

Wednesday, August 31 – Tonight at sunset, return again to the western horizon to have a look at our bright planetary pairing. Just 24 hours before their closest approach, you will see brilliant Venus only one and a half degrees below the Mighty Jove. This is a picture-perfect moment of our solar system’s orbits, so be sure to watch and tomorrow night brings this pair even nearer together.

Tonight will be the peak of the Andromedid meteor shower. With the Moon in our favour and the constellation of Cassiopeia already risen, let’s take a break from our studies and watch the show. For those of you in the northern hemisphere, look for the lazy “W” of Cassiopeia to the northeast. This is the radiant – or relative point of origin – for this meteor stream. At times, this shower has been known to be spectacular, but let’s stick with an accepted fall rate of around 20 per hour. These are the offspring of Beila’s Comet and have a reputation for red fireballs with spectacular trains. Happy “trails” to you!

Thursday, September 1 – In 1859, solar physicist – Richard Carrington, who originally assigned sunspot rotation numbers – observed the first solar flare ever recorded. Naturally enough, an intense aurora followed the next day. 120 years later in 1979, Pioneer 11 makes history as it flies by the Saturn. We often take our progress in space for granted, but look at how much has been achieved in just our lifetimes. A great many of us were born well before space exploration started, and quite a few of us well remember 1979. As we tip our hats toward Saturn this morning, realize in just a short period of 25 years that we have gone from just flying past Saturn to actually having landed on one of its moons.

This is it. Mark your calendars for today and take your family out to view the visually most striking planetary pairing of the year! On the western horizon just after sunset, Venus and Jupiter will have now moved to just slightly over one degree apart. Don’t miss your opportunity to photograph or witness this stunning event!

Tonight we are going to take a journey once again toward an area which has intrigued this author since I first laid eyes on it with a telescope. Some think it difficult to find, but there is a very simple trick. Look for the primary stars of Sagitta just to the west of bright Albireo. Make note of the distance between the two brightest and look exactly that distance north of the “tip of the arrow” and you’ll find the M27.

Discovered in 1764 by Messier in a three and a half foot telescope, I discovered this 48,000 year old planetary nebula for the first time in a 4.5″ telescope. I was hooked immediately. Here before my eager eyes was a glowing green “apple core” which had a quality about it that I did not understand. It somehow moved… It pulsated. It appeared “living”.

For many years I quested to understand the 850 light year distant M27, but no one could answer my questions. I researched and learned it was made up of doubly ionized oxygen. I had hoped that perhaps there was a spectral reason to what I viewed year after year – but still no answer. Like all amateurs, I became the victim of “aperture fever” and I continued to study the M27 with a 12.5″ telescope, never realizing the answer was right there – I just hadn’t powered up enough.

Several years later while studying at the Observatory, I was viewing through a friend’s identical 12.5″ telescope and as chance would have it, he was using about twice the magnification that I normally used on the “Dumbbell”. Imagine my total astonishment as I realized for the very first time that the faint central star had an even fainter companion that made it seem to wink! At smaller apertures or low power, this was not revealed. Still, the eye could “see” a movement within the nebula – the central, radiating star and its companion.

Do not sell the “Dumbbell” short. It can be seen as a small, unresolved area in common binoculars, easily picked out with larger binoculars as an irregular planetary nebula, and turns astounding with even the smallest of telescopes. In the words of Burnham, “The observer who spends a few moments in quiet contemplation of this nebula will be made aware of direct contact with cosmic things; even the radiation reaching us from the celestial depths is of a type unknown on Earth…”

Friday, September 2 – If you were clouded out last night, don’t worry. Both Venus and Jupiter are still making an awesome appearance on the western sunset horizon. Now separated by about a degree and a half, watch in the days ahead as the planets once again begin to distance themselves and slowly head away towards the Sun.

When skies are dark, it’s time for us to head directly between the two lower stars in the constellations of Lyra and grab the “Ring”.

First discovered by French astronomer, Antoine Darquier in 1779, the “Ring” was cataloged later that year by Charles Messier as the M57. In binoculars the “Ring” will appear as slightly larger than a star, yet it cannot be focused to a sharp point. To a modest telescope at even low power, the M57 turns into a glowing donut against a wonderfully stellar backdrop. The average accepted distance to this unusual structure is believed to be around 1,400 light years and how you see the “Ring” on any given night is highly attributable to conditions. As aperture and power increase, so do details and it is not impossible to see braiding in the nebula structure with scopes as small as eight inches on a fine night, or to pick up the star caught on the edge in even smaller apertures.

Like all planetary nebula, seeing the central star is considered the ultimate of viewing. The central itself is a peculiar bluish dwarf which gives off a continuous spectrum and might very well be a variable. At times, this shy, near 15th magnitude star can be seen with ease with a 12.5″ telescope, yet be elusive to 31″ in aperture weeks later. No matter what details you may see, reach for the “Ring” tonight. You’ll be glad you did.

Saturday, September 3 – Tonight is New Moon and a great opportunity to have another look at all the things we’ve studied this week. However, I would encourage those of you with larger binoculars and telescopes to head for a dark sky location, because tonight we are going on a quest…

The quest for the holy “Veil”.

By no means is the Veil Nebula Complex an easy one. The brightest portion, NGC 6992, can be spotted in large binoculars and you can find it just slightly south of a central point between Epsilon and Zeta Cygnii. The NGC 6992 is much better in a 6-8″ scope however, and low power is essential to see the long ghostly filaments which span more than a degree of sky. About two and a half degrees west/southwest, and incorporating star 52 is another long narrow ribbon of what may be classified as a supernova remnant. When aperture reaches the 12″ range, so does the true breadth of this fascinating complex. It is possible to trace these long filaments across several fields of view. They sometimes dim and at other times widen, but like a surreal solar flare, you will not be able to tear your eyes away from this area. Another undesignated area lies between the two NGCs, and the whole 1,500 light year distant area spans over two and a half degrees. Sometimes known as the “Cygnus Loop”, it’s definitely one of the summer’s finest objects.

If you’re out after midnight, be sure to have a look at growing Mars. In 1976, the Viking 2 lander touched down on Mars – about 7 weeks after Viking 1. Both Spirit and Opportunity are still going strong, so don’t miss out on this year’s adventures to the Red Planet.

Sunday, September 4 – No luck at spotting Mercury just before dawn? Then grab your binoculars this morning and look bright Regulus on the horizon. You’ll find the speedy inner planet about one degree to Regulus’ north.

Skies will still be very dark tonight, Of course, studying some of the summer’s finest means that we’d be very remiss if we didn’t look at another cosmic curiosity – “The Blinking Planetary”.

Located a couple of degrees east of visible star Theta Cygnii, and in the same lower power field as 16 Cygnii, the NGC 6826 is often referred to as the “Blinking Planetary” nebula. Viewable in even small telescopes at mid to high power, you’ll learn very quickly how it came about its name. When you look directly at it, you can only see the central 9th magnitude star. Now, look away. Focus your attention on visual double 16 Cygnii. See that? When you avert, the nebula itself is visible. This is actually a trick of the eye. The central portion of our vision is more sensitive to detail and will only see the central star. At the edge of our vision, we are more likely to see dim light, and the planetary nebula appears. Located around 2,000 light years from our solar system, it doesn’t matter if the “Blinking Planetary” is a trick of the eye or not… Because it’s cool!

I hope you enjoy this week’s studies, because I thoroughly intend to do the same at the Black Forest Star Party! Let’s hope we all have clear skies. Now, I’m outta’ here until the Moon returns. Until then? May all your journeys be at light speed…~Tammy Plotner

The Moon and Venus Credit: Robert Sandy
Monday, August 8 – About an hour after sunset, look for the crescent Moon low in the west/southwest for northern hemisphere viewers. Check out Venus less than a fist’s width to its lower right and Jupiter less than a handspan to upper left. We’ll keep watch this week as the Moon passes by Jupiter and bright stars – Spica and Antares.

For viewers in Alaska, here’s a unique opportunity… Tonight you’ll have a chance to see the Moon occult Venus! Need a time for your location? Then look no further than this IOTA webpage. For our friends in the UK, you will have the opportunity to watch the Moon occult Beta Virginis tonight. Please check this IOTA webpage for listings of times and cities in your area. Wishing you both clear skies…

For the rest of us, take the time tonight to really study the fully emerged Mare Crisium region telescopically. Look for the small punctuation of craters Pierce toward the northwestern area and Pickard to its south. Can you make out the bright peninsula of Promentorium Agarum on the eastern shore?

Tuesday, August 9 – Tonight after sunset, look again at the crescent Moon and you’ll discover that Jupiter now sits a few scant degrees above its left shoulder. When the stars begin to appear, look for bright Spica about a fist width south of Jupiter.

Tonight we’ll have a look at the smooth sands of Mare Fecunditatis to the lunar south. Binoculars will see the bright, shallow ring of Langrenus on its eastern shore. For telescopic users, this is a great opportunity to pick up two small challenge craters located just northwest of central in Fecunditatis – crater Messier to the east and its companion crater Messier A to the west.

Wednesday, August 10 – For viewers along the eastern sections of both Canada and the US, get your binoculars out and have a look at the Moon right after sunset. Just below the southern cusp you will spot Spica. Watch over the next two hours as the skies fully darken and the distance between them widens as the pair sets.

On the lunar surface, look for the three rings of Theophilus, Cyrillus and Catherina on the edge of Mare Nectaris to the south. A bit further south, you will note a long bright feature known as Rupes Altai, or commonly referred to as the Altai Scarp. This 967 km (600 mile) long feature stretches in an arc from crater Piccolomini through the south shore of Mare Tranquillitatus. While its height doesn’t exceed more than 1.6 – 3.2 km (1 to 2 miles), lunar sunrise highlights it to perfection and you will notice that it is much stronger to the south.

Thursday, August 11 – On this date in 1877, Asaph Hall of the U.S. Naval Observatory was very busy. Tonight would be the first time he would first see Mars’ outer satellite Deimos! Six nights later, he observed Phobos, giving Mars a grand total of two moons. Be sure to watch as Mars begins rising around midnight.

Tonight is the peak of the Perseid meteor shower, but we’ll need to kill about three hours until the Moon sets. If you can’t nap, then look for Venus low on the horizon and notice that Jupiter and Spica are slightly closer together. On the lunar surface, binoculars will see the central Mare Tranquillitatus. For telescope users, on its eastern shore you will see the small bright ring of crater Arago – but don’t stop there. Continue east towards the terminator and watch for a thin, black line that cuts through the foothills. While most rilles are usually within mare areas, the Rimae Ariadaeus is one of the few sufficiently wide enough to be spotted against such a bright background. Running around 233 km (145 miles) long, this is known as a Graben type depression and it only averages around 1.6 – 3.2 km (1 – 2 miles) wide. Although it appears relatively straight, it’s actually a collection of offset segments.

Now let’s sit back and talk about the Perseids while we watch…

The Perseids are undoubtedly the most famous of all meteor showers and never fail to provide an impressive display. Its activity appears all the way back to 36 AD in Chinese history. In 1839, Eduard Heis was the first observer to give an hourly count and discovered their maximum rate was around 160 per hour at that time. He, and other observers, continued their studies in subsequent years to find that number varied.

Giovanni Schiaparelli was the first to relate the orbit of the Perseids to periodic comet Swift-Tuttle (1862 III). The fall rates have both risen and declined over the years as the Perseid stream was studied more deeply and many complex variations discovered. There are actually four individual streams derived from the comet’s 120 year orbital period which peak on slightly different nights, but tonight is our accepted peak.

Meteors from this shower enter Earth’s atmosphere at a speed of 60 km/sec (134,000 miles per hour), from the general direction of the border between the constellations Perseus and Cassiopeia. While they can be seen anywhere in the sky, if you extend their paths backward, all the true members of the stream will point back to this region of the sky. For best success, position yourself so you are generally facing northeast and get comfortable. The radiant will continue to climb higher in the sky as dawn approaches. Around midnight, watch as Mars joins the show and Saturn honors us in the east about an hour before sunrise.

Wishing everyone success!

Friday, August 12 – Practice astronomy in the daytime? Why not! When the Sun reaches its highest point today in the northern hemisphere, you see the Moon rising in the southeast. Watch as the skies darken and you’ll discover red Antares about a handspan to its left.

Tonight let’s return to the lunar surface to pick up another surface “scar”. In the north you will see the rugged terrain of the Montes Alpes. Look for the deep, diagonal gash of the Alpine Valley cutting through them. This artificial looking feature runs around 177 km (110 miles) long and ranges anywhere from 1.6 – 21 km (1 – 13) miles wide. It’s a very curious feature and may very well be a reminder of a glancing blow dealt by a large meteoritic body.

Saturday, August 13 – Tonight Antares is less than a fist width away from the waxing gibbous Moon. On the lunar surface, we can enjoy another strange, thin feature as well. Look toward the lunar south where you will note the prominent rings of craters Ptolemaeus, Alphonsus, Arzachel, Purbach and Walter descending from north to south. Just west of them, you’ll see the emerging Mare Nubium. Between Purbach and Walter you will see the small, bright ring of Thebit with a crater caught on its edge. Look further west and you will see a long, thin, dark feature cutting across the mare. Its name? Rupes Recta – better known as “The Straight Wall”. It is one of the steepest known lunar slopes rising around 366 meters (1200 feet) from the surface at 41 degree angle.

Sunday, August 14 – Look again at the sky tonight as Antares has now moved to the other side of the Moon! For New Zealand and Australia, you will have the chance to see the Moon occult Sigma Scorpii. You can find details on this IOTA webpage. On this same night, viewers in central northern Australia (in the Broome/Darwin area) will also have a chance to see the Moon occult Antares. Please check this IOTA webpage for precise times.

For lunar binocular viewers this evening, two wonderful features are readily awaiting you. Look for the smooth, dark oval of Plato to the north and the emerging grandeur of Copernicus almost central to the terminator. Can you see the wonderful Archimedes between the two – or Eratosthenes hanging onto the tail of the Apennine Mountains?

Until next week, may all your journeys be at light speed…~Tammy Plotner

M107. Image credit: NOAO/AURA/NSF. Click to enlarge.
Monday, July 25 – With the later rise of the Moon this week, we’ll have the opportunity to do some study of globular clusters. Let’s start with one that is often overlooked – M107. Discovered by Pierre Mechain in 1782, and added to the catalog in 1947, it’s probably one of the latest of the Messier objects to be discovered and wasn’t resolved into individual stars until studied by Herschel in 1793.

Located about one quarter the distance between Zeta Ophiuchius and Beta Scorpius, the M107 isn’t the most impressive of globulars, but it is surprisingly bright in a small telescope. It’s a curious cluster, for some believe it contains dark, dust obscured areas which makes it unusual. Located around 21,000 light years away, this little beauty contains around 25 known variable stars. Visually, the cluster begins to resolve around the edges to mid-aperture and the structure is rather loose. If sky conditions permit, the resolution of individual chains at the globular’s edges make this globular well worth a visit.

Tuesday, July 26 – Tonight let’s continue on our journey through the galactic halo and pick up the M9 located around 3 and a half degrees east of Eta Ophiuchus. Discovered by Messier in 1764, this particular globular cluster is one of the nearest to our galactic center, and is around 2,600 light years away from our solar system. Now let’s notice differences – check out the contrast between this small globular’s appearance as compared to last night’s M107. At this point we’re seeing not only a strong central concentration, but a slight oval shape. This change in structure is caused by the strong absorption of star light by dust along its northwest edge. Of its huge stellar population, only a dozen or so variable stars are known in M9, which is rather few for a cluster of its size. Visually, it appears more compact and slightly oblate. Rather than chains of stars resolving at the edges, the M9 appears to have larger, individual stars in a random pattern.

For those with larger scopes, you also have the opportunity to study two more that are nearby – NGC 6356 about a degree to the northeast and NGC 6342 to the southeast. You will find the NGC 6356 to be rather small – but bright. The NGC 6342 appears to be even smaller and far less distinct. Compare them both to the structure of the M9 and you will find the 6356 to be the most concentrated of the three.

Wednesday, July 27 – This morning the Moon dances with Mars. Luna will appear about half a fist width to the northwest (upper right) of the Red Planet just before dawn.

Tonight we’re going monster hunting, and heading about a fist’s width north of Beta Librae towards a previous study – double star 5 Serpens and the glorious M5. First discovered by Kirch in 1702, re-discovered by Messier in 1764, and resolved by in 1791 by Herschel, this fifth brightest globular cluster in the sky is considered to be one of the most ancient and may be as many as 13 billion years old.

Further away from the dusty galactic center, resolution explodes as the viewer moves up in aperture. Easily seen as roundish ball of unresolved stars in binoculars, even small scopes will begin to pick individual stellar points out of this mass and begin to realize that the M5 is not perfectly round. Its brighter stars are also distributed randomly and it contains an unusually large number of variables. Note its structure. While it is far more grand than the others we have observed, it is far less concentrated at the core.

Thursday, July 28 – This morning the Moon has waltzed to the other side of Mar’s position, putting it about a fist width to the planet’s northwest. Notice that Mars continues to brighten and will soon have reached -1 magnitude as it moves toward the Sun. Today in 1851, the first photograph of the Sun was made during a total eclipse revealing the corona for the first time.

Tonight we will hustle off to explore a single small globular – M80. Located about 4 degrees northwest of Antares (half a fist), this little globular cluster is a powerpunch. Located in a region heavily obscured by dark dust, the M80 will shine like an unresolvable star to small binoculars and reveal itself to be one of the most heavily concentrated globulars to the telescope. Discovered within days of each other by Messier and Mechain respectively in 1781, this intense cluster is around 36,000 light years distant.

In 1860, the M80 became the first globular cluster to contain a nova. As stunned scientists watched, a centrally located star brightened to magnitude 7 over a period of days and became known as T Scorpii. The event then dimmed more rapidly than expected, making observers wonder exactly what they had seen. Since most globular clusters contain stars all of relatively the same age, the hypothesis was put forward that perhaps they had witnessed an actual collision of stellar members. Given the cluster contains more than a million stars, the probability remains that some 2700 collisions of this type may have occurred during the M80’s lifetime.

Now grab a comfortable seat because the Delta Aquarid meteor shower reaches its peak tonight. It is not considered a prolific shower, and the average fall rate is about 25 per hour – but who wouldn’t want to take a chance on observing a meteor about every 4 to 5 minutes? These travellers are considered to be quite slow, with speeds around 24 kilometers per second and are known to leave yellow trails. One of the most endearing qualities of this annual shower is its broad stream of around 20 days before and 20 days after peak. This will allow it to continue for at least another week and overlap the beginning stages of the famous Perseids.

The Delta Aquarid stream is a complicated one, and a mystery not quite yet solved. It is possible that gravitation split the stream from a single comet into two parts, and each may very well be a separate stream. One thing we know for certain is they will seem to eminate from the area around Capricornus and Aquarius, so you will have best luck facing southeast and getting away from city lights. On a personal note, I have observed high activity from the region for the last two weeks, which means we may be passing through a more heavily concentrated portion of the stream. While I cannot guarantee you’ll see significant activity, I highly urge you to enjoy a warm summer night and take a chance at “catching a shooting star”.

Friday, July 29 – The weekend has arrived at last, and if you have not had the chance to observe the earlier globular clusters, pick them up tonight and let’s head on out towards two more giants that appear differently from the rest (and each other) – previous study M10 and M12.

Located about half a fist width west of Beta Ophiuchus, the M12 is the northern most of this pair. Easily seen as a hazy round spot in binoculars, let’s find out what makes it tick. Since this large globular is much more loosely concentrated, smaller scopes will begin to resolve individual stars from this 24,000 light year distant cluster. Note there is a slight concentration toward the core region, but for the most part the cluster appears fairly even. Large instruments will resolve out individual chains and knots of stars.

Now let’s drop about 3 and half degrees southeast and check out M10. What a difference in structure! Although they seem to be close together and close in size, the pair are actually separated by some 2,000 light years. The M10 is a much more concentrated globular showing a brighter core region to even the most modest of instruments. This compression of stars is what classifies one type of globular cluster from another and M10 appears brighter, not because of this compression, but because it is about 2,000 light years closer.

Saturday, July 30 – Before sunrise this morning look for the waning crescent Moon as it travels along the returning constellation of Taurus. Aldebaran, the “eye of the bull” will appear about a fist width below Selene. The Pleiades will complete the scene as it appears about half a fist width to the Moon’s upper right. Take out your binoculars to take a peek at the “Seven Sisters”.

For central through western Australia and toward Indonesia, viewers will have the opportunity to see the Moon occult the Pleiades. This is an event you won’t want to miss, so please check this IOTA webpage to get precise times in your location. Clear skies!

For hard core observers, tonight’s globular cluster study will require at least a mid-aperture telescope, because we’re going after a same field pair – NGC 6522 and NGC 6528. You will find them easily at low power just a breath northwest of Gamma Sagittarius, better known as Al Nasl – or the tip of the “teapot’s” spout. Once located, switch to higher power to keep Gamma out of the field and let’s check them out.

The brighter, and slightly larger, of the pair to the northeast is NGC 6522. Note its level of concentration and compared to NGC 6528. Both are located around 2,000 light years away from the galactic center and seen through a very special area of the sky known as “Baade’s Window” – one of the few areas towards our galaxy’s core region not obscured by dark dust. While each are similar in concentration, distance, etc., the NGC 6522 has a slight amount of resolution towards its edges while the 6528 appears more random.

Now, relax and enjoy the peak of the Capricornid meteor shower! Although it is hard for the casual observer to distinguish these meteors from the Delta Aquarids, no one minds. Again, face the general direction of southeast and enjoy! The fall rate for this shower is around 10 to 35 per hour, but unlike the Aquarids, this stream produces those great “fireballs” known as bolides. Enjoy…

Sunday, July 31 – For viewers in eastern and central Australia and all of New Zealand, you will have the opportunity to see the Moon occult Beta Tauri this morning. Please check this IOTA webpage for times and locations in your area.

Tonight we’re going to move back toward Ophiuchus and a globular cluster unlike any that we’ve seen so far – M19. Locate Antares and about a fist width to the east you will see Theta Ophiucus with fainter star 44 to its northwest and multiple system 36 to the southeast. Move around 2 degrees to the west of 36 and let’s check it out.

With a visual magnitude of 6.8, this class VIII globular cluster can be seen with small binoculars, but requires a telescope to begin to take on form. Discovered by Charles Messier in 1764, the M19 is the most oblate globular known. Harlow Shapely, who studied globular clusters and cataloged their elliptical natures, estimated about twice as many stars along the major axis as along the minor. This stretching of the cluster from its accepted round shape may very well have to do with its proximity to the Galactic Center – a distance of only about 5,200 light years. This makes it only a tiny bit more remote from us than the very center of the Milky Way!

Very rich and dense, even smaller telescopes can pick up that this globular cluster has a faint blue tinge to it. It is definately one of the more interesting, due to its shape, but for the adventurous? There’s two more. The NGC 6293 is about a degree and a half to the east/southeast and is far brighter than you might expect. Note how much more round and concentrated directly at the core this companion is. Now move about a degree and a half to the north/northeast of M19 to find dimmer NGC 6284. Although it is the same size as the 6293, look at how much more “loose” this one is constructed!

Our globular cluster studies will continue next week, so stick around! In the mean time? May all your journeys be at Light Speed… ~Tammy Plotner