Category: Observing

Greetings, fellow SkyWatchers! Did you happen to see the close appearance of the Moon and Jupiter last night? If you thought that was fun, they’re about to get a whole lot closer tonight – and have company! With a bit darker skies this weekend, it looks like a good time to go globular and explore a few of the summer’s finest. But what weekend would be complete without a little treat? I have one in mind just for you. Follow me…

Friday, July 10, 2009 – If you’re out when the Moon rises, look for the asteroid Psyche nearly brushing the limb 0.2 degrees north. You’ll find the pairing of Jupiter and Neptune about a degree and a half apart and a little more than a finger-width south!

Today we celebrate the 1832 birth on this date of Alvan Graham Clark. An astronomer himself, Clark was also a member of a famous American family of telescope makers. He helped to create the largest refractor in the world—the lenses for the 4000 Yerkes Telescope. Perhaps the stress of worrying for their safety took its toll on Alvan, for he died shortly after their first use.

Before the Moon rises tonight, let’s honor Clark’s work by studying a globular cluster suitable for all optics, M4. All you have to know is Antares! Just slightly more than a degree west (RA 16 23 35 Dec –26 31 31), this major 5th magnitude Class IX globular cluster can even be spotted unaided from a dark location. In 1746 Philippe Loys de Cheseaux happened upon this 7,200-light-year-distant beauty, one of the nearest to us. It was also included in Lacaille’s catalog as object I.9 and in Messier’s in 1764. Much to Charles’s credit, he was the first to resolve it!

As one of the loosest, or most ‘‘open’’ 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 to resolve 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, in 1987, the first millisecond pulsar was discovered within M4, which turned out to be ten 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 Solar System!

Saturday, July 11, 2009 – Today marks the 1732 birth on this date of Joseph Jerome Le Francais de Lalande, who determined the Moon’s parallax and published a comprehensive star catalog in 1801.

Tonight let’s head on out toward two more giants that appear differently from the rest (and each other) – same-field binocular pair M10 and M12. Located about half a fist-width west of Beta Ophiuchi, M12 (RA 16 47 14 Dec –01 56 52) is the northern most of this pair. Easily seen as two hazy round spots in binoculars, let’s go to the telescope to find out what makes M12 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 Class IX cluster. Note that 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 3.5 degrees southeast and check out Class VII M10 (RA 16 57 08 Dec –04 05 57). What a difference in structure! Although they seem to be close together and similar in size, the pair is actually separated by some 2,000 light-years. 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 differentiates one type of globular cluster from another and is the basis of their classification. M10 appears brighter, not because of this compression but because it is about 2,000 light-years closer than M12!

Sunday, July 12, 2009 – Today marks the 1682 passing of Jean Picard. No, not he of Star Trek fame but the Jesuit astronomer who created a movable-wire micrometer to measure the diameters of celestial objects such as the Sun, Moon, and planets!

For hard-core 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 same-low-power-field pair—NGC 6522 (RA 18 03 34 Dec –30 02 02) and NGC 6528 (RA 18 04 49 Dec –30 03 20). You will find them easily at low power just a breath northwest of Gamma Sagittarii, better known as Al Nasl, 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 study. The brighter, and slightly larger, of the pair to the northeast is Class VI NGC 6522. Note its level of concentration compared to the Class V NGC 6528. Both are located around 2,000 light years away 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. Although each is similar in concentration, distance, etc., NGC 6522 has a slight amount of resolution toward its edges, while NGC 6528 appears more random.

Although both NGC 6522 and NGC 6528 were discovered by Herschel on July 24, 1784, and both are the same distance from the galactic core, they are very different. NGC 6522 has an intermediate metallicity. At its core, the red giants have been depleted, or stripped tidally by evolving into 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!

Before you go, why not travel to Lupus and discover Theta, about a fist-width south-southwest of the mighty Antares (RA 16 06 35 Dec –36 48 08). Although this rather ordinary looking 4th magnitude star appears to be nothing special, there’s a lesson to be learned here. So often in our quest to look at the bright and incredible—the distant and impressive—we often forget about the beauty of a single star. When you take the time to seek the path less traveled, you just might find more than you expected. Hiding behind a veil of ‘‘ordinariness’’ is a trio of three spectral types and three magnitudes in a diamond-dust field. An undiscovered gem…

Until next week? Enjoy your beautiful starry nights when you have them. Before you turn down a chance to watch a waning July moonrise… think of how many July moon rises you may have left. Savor each moment and delight in all that’s around you. The rewards are stellar!

This week’s awesome images are (in order of appearance): Alvan Clark with Yerkes objective (historical image), M4, M12, M10, NGC 6522, NGC 6528 and Theta Lupi (credit—Palomar Observatory, courtesy of Caltech). We thank you!

Greetings, fellow SkyWatchers! Are you ready for a Moon-filled weekend? Then let’s have a look a some great lunar features as we race Mad Max to the “Megadome”! For some lucky viewers in Japan and Hawaii, there will be an occultation of Antares to enjoy. How about some great double stars… Or a chance to see if you can spot a penumbral lunar eclipse? Then follow me out to the backyard. The stars are waiting…

Friday, July 3, 2009 – Tonight let’s venture toward the south shore of Palus Epidemiarum to have a high-power look at crater Capuanus. Named for Italian astronomer Francesco Capuano di Manfredonia, this 60 kilometer-wide crater boasts a still tall southwest wall, but the northeast one was destroyed by lava flow.

At its highest, it reaches around 1,900 meters above the lunar surface, yet drops to no more than 300 meters at the lowest. Look for several strikes along the crater walls as well as more evidence of a strong geological history. To the north is the Hesiodus Rima, a huge fault line that extends 300 kilometers across the surface!

When you’re done, why not have a look at 156-light-year-distant Mu Serpentis (RA 15 49 37 Dec –03 25 48)? Its name is Leiolepis, which means ‘‘smooth scaled.’’ Perhaps a fitting name, because this normal A-type main sequence star is also known as the head of the serpent. Have a look in binoculars, and you’ll note several optical companions. Or use a telescope to locate delicate binary Struve 1985 (RA 15 56 01 Dec –02 11 00) nearby!

Saturday, July 4, 2009 – Look closely at the Moon. For some lucky viewers, it’s about to occult Antares! Check International Occultation and Timing Association (IOTA) for times and locations.

Also be sure to look for the ‘‘Cow Jumping over the Moon,’’ but power up with a telescope to study some very wild looking features—lunar lava domes. North of Aristarchus, west of Promontorium Heraclides, and near the terminator is Rumker—the largest of the lava domes. Only visible when near the terminator, this roughly 77-kilometer-diameter ‘‘soft hill’’ ranges anywhere from 60 to 760 meters tall. Although it is not much more than a bump on the lunar surface, it does contain a few summit craters at its highest points. What we are looking at is really an important part of the geology that shaped the Moon’s surface. In all likelihood, Rumker is a shield volcano. . .in an area of many!

Now continue east toward the prominent crater Marian, set in a bright peninsula extending into Sinus Roris and Mare Imbrium. Just southwest are two more—Mons Gruithuisen Gamma (the ‘‘Megadome’’) and Mons Gruithuisen Delta. Although you might not find these features particularly impressive, consider that we’re looking at something only 20 kilometers wide and only a few meters high!

Tonight we honor American astronomer Henrietta Swan Leavitt, the discoverer of the relationship between period and luminosity in Cepheid variables. This led to understanding the distance to the galaxies! Said Leavitt, ‘‘Since the variables are probably nearly the same distance from Earth, their periods are apparently associated with their actual emission of light, as determined by their mass, density, and surface brightness.’’ Do her memory honor and check out Delta Cephei (RA 22 29 10 Dec þ58 24 54) tonight! Thirty to forty times more massive than our own Sun, Delta varies from magnitude 3.6–4.3 in just slightly over 5 days. And look for its companion star as well.

Sunday, July 5, 2009 – Tonight let’s go deep south and have look at an area that once held something almost half a bright as tonight’s Moon and over four times brighter than Venus. Only one thing could light up the skies like that—a supernova.

According to historical records from Europe, China, Egypt, Arabia, and Japan, 1,003 years ago the very first supernova event was noted. Appearing in the constellation of Lupus, it was at first believed to be a comet by the Egyptians, yet the Arabs saw it as an illuminating ‘‘star.’’ Located less than a finger-width northeast of Beta Lupi (RA 15 02 48 Dec –41 54 42) and half a degree east of Kappa Centaurus, no visible trace is left of a once-grand event that spanned 5 months of observation, beginning in May and lasting until it dropped below the horizon in September 1006. It is believed that most of the star was converted to energy, and very little mass remains. In the area, a 17th magnitude star that shows a tiny gas ring and radio source 1459-41 remains our best candidate for pinpointing this incredible event.

Why you’re at it, try a challenging double star—Upsilon Librae (RA 15 37 01 Dec –28 08 06). This beautiful red star is right at the limit for a small telescope, but quite worthy, as the pair is a widely disparate double. Look for the 11.5-magnitude companion to the south in a very nice field of stars!

If you’d like to try for a challenging observation, then take look on the universal date of July 7th for a partial penumbral eclipse. While this isn’t anything to get intensely excited over, since the Moon will only graze through a small portion of the Earth’s shadow, chances are you might just notice something a little different. While a certain very reputable periodical says “The moon skims through too little of the penumbra to be noticed even by the most intent observer.” – I have also heard them say things like the partial solar eclipse won’t be visible here or there – and proved them wrong. It’s only my opinion, of course, but I believe no one should be discouraged from making an observation if they have the time, the energy, the location or the desire! So here’s what to do…

The partial penumbral eclipse will be seen starting in eastern Australia as the Moon rises just after dusk on July 7th and it will occur as the Moon is setting over western North and South America in the early predawn hours of July 7th. Only the northern third of the lunar surface will be affected, and it will be just a slight change in coloration – a vague gray shadowing. However, this is simply a prediction on the vague part! I have seen times when this happens that the appearance is very noticeable, and times when you truly can’t tell at all. Why not judge for yourself? I look forward to hearing your results!

Good luck and clear skies…

This week’s awesome images are: Capuanus, Marian and the Megadome (credit—Wes Higgins), Mu Serpentis, Delta Cephei, Field of SN 1006 and Upsilon Librae (credit – Palomar Observatory, courtesy of Caltech). We thank you so much!

Greetings, fellow SkyWatchers! It’s another lunatic weekend as we start off with Regulus and Selene making a close pairing in the Friday evening sky. Why not take a break from difficult galaxy studies and try your hand at some very cool variable stars and multiple systems? It’s time to get out your telescopes and binoculars, pick off a few lunar challenge craters and just kick back and enjoy because… Here’s what’s up!

Friday, June 26, 2009 – Happy Birthday, Charles Messier! Born in 1730 on this date, almost everyone recognizes the name of this French astronomer who discovered 15 comets. He was the first to compile a systematic catalog—the ‘‘M objects.’’ The Messier Catalogue (1784) contains 103 star clusters, nebulae, and galaxies. But did you know Lyman Spitzer, Jr, shared this birthday? Born in 1914, Spitzer advanced our knowledge of physical processes in interstellar space and pioneered efforts to harness nuclear fusion as a clean energy source. He studied star-forming regions and suggested that the brightest stars in spiral galaxies formed recently. Not only that, but Spitzer was the first person to propose placing a large telescope in space, and so launched the development of the Hubble Space Telescope!

Tonight the mighty Regulus will be very close to the Moon, providing a wonderful opportunity for stargazers. Why not grab a telescope and view the lunar surface for a couple of telescopic challenges that are easy to catch? All you have to know is Mare Crisium!

On the southeastern shoreline is a peninsula that reaches into Crisium’s dark basin. This is Promontorium Agarum. On the western shore, bright Proclus lights the banks, but look into the interior for the two dark pockmarks of Pierce to the north and Picard to the south. Be sure to mark them on your notes!

When you’re finished, point your binoculars or telescopes back toward Corona Borealis and about three finger-widths northwest of Alpha for variable star R (RA 15 48 35 Dec +28 09 24). This star is a total enigma. Discovered in 1795, most of the time R carries a magnitude near 6 but can drop to magnitude 14 in a matter of weeks—only to unexpectedly brighten again! It is believed that R emits a carbon cloud, which blocks its light. Oddly enough, scientists can’t even accurately determine the distance to this star! When studied at minimum, the light curve resembles a ‘‘reverse nova’’ and has a peculiar spectrum. It is very possible that this ancient Population II star has used all of its hydrogen fuel and is now fusing helium to form carbon.

Saturday, June 27, 2009 – Tonight we’ll again honor the June 26 birth of Charles Messier by heading toward the lunar surface first, in order to pick off another study object on our list—the twin crater pair Messier and Messier A.

Located in Mare Fecunditatis about a third of its width from west to east, these two craters will be difficult to find in binoculars, but not hard for even a small telescope and intermediate power. Indeed named for the famed French astronomer, the easternmost crater is somewhat oval in shape, with dimensions of 9 by 11 kilometers. At high power, Messier A to the west appears to have overlapped a smaller crater during its formation; and it is slightly larger at 11 by 13 kilometers. Although it is not on the challenge list, you’ll find another point of interest to the northwest. Rima Messier is a long surface crack, which runs diagonally across Mare Fecunditatis’s northwestern flank and reaches a length of 100 kilometers.

For variable star fans, let’s return to and focus our attention on S Coronae Borealis, located just west of Theta and the westernmost star in the constellation’s arc formation (RA 15 21 23 Dec +31 22 02). At magnitude 5.3, this long-term variable takes almost a year to go through its changes—usually far outshining the 7th magnitude star to its northeast—but will drop to a barely visible magnitude14 at minimum. Compare it to the eclipsing binary U Coronae Borealis about a degree northwest. In slightly over 3 days, this Algol-type will range by a full magnitude as its companions draw together.

Sunday, June 28, 2009 – As we head out into the night, let’s observe a moment of silence to remember the 1889 passing on this date of Maria Mitchell, the first professional woman astronomer. While pursuing amateur astronomy, she gained fame from her October 1, 1947, observation of a comet, about which she was the first to report. Mitchell was also the first female member of the American Academy of Arts and Sciences. Said Mitchell, ‘‘The eye that directs a needle in the delicate meshes of embroidery will equally well bisect a star with the spider web of the micrometer.’’

Tonight let’s honor Mitchell by locating the lunar crater named in her honor. Begin by visiting the northeast quadrant of the Moon and identify crater Aristoteles. On its eastern edge, you’ll find Mitchell. Measuring only 30 kilometers in diameter, it is dwarfed by Aristoteles’ 87-kilometer diameter, but Maria Mitchell was never dwarfed in life!

To further honor Mitchell, let’s have a look at the 250-light-year-distant silicon star Iota Librae (RA 15 12 13 Dec -19 47 28). This is a challenge for binoculars, but not because the components are so close. In Iota’s case, the near 5th magnitude primary simply overshadows its 9th magnitude companion!

In 1782, Sir William Herschel measured them and determined they were a true physical pair. Yet, in 1940 Librae A was determined to have an equal-magnitude companion only 0.2’’ away. . .and the secondary was proved to have a companion of its own, which echoes the primary. A four-star system!

Until next week? Keep an eye on the sky for members of the June Draconid meteor shower which peaks Tuesday morning! Wishing you clear skies….

This week’s awesome photos are (in order of appearance): Lyman Spitzer (credit—
courtesy of hubblesite.org), Mare Crisium (credit—Greg Konkel), Mare Fecunditatis and Messier/Messier A (credit—Greg Konkel), S Coronae Borealis (credit—Palomar Observatory, courtesy of Caltech), Aristoteles and Mitchell (credit—Wes Higgins) and Iota Librae (credit—Palomar Observatory, courtesy of Caltech). We thank you so much!

Greetings, fellow SkyWatchers! You asked for some excitement? You got it. As it the current planetary line up wasn’t treat enough for the weekend, there’s still lots more to go. With dark skies around, we’ll be taking on some challenging studies like faint objects near bright stars… But we won’t be forgetting to chase “Butterflies”! The Celestial Scenery just keeps getting better as the weekend rolls on with a Saturday morning meteor shower. Why not grab coffee and donuts and make a date to watch? The planetary conjunction continues with a close pass on the Pleiades, too. Join the merry-go-round of stars and grab for the “Ring”! Summer Solstice is upon us and there’s no place I’d rather be than out back with you viewing the stars…

Friday, June 19, 2009 – This morning, begin by noting the 1846 birth on this date of Italian astronomer, Antonio Abetti. Although his name might seem a bit obscure, what he studied was not—small planets, comets, and star occultations. This morning your mission is to observe one of the nicest alignments you’ll see this year—the Moon, Venus, and Mars. Look for this beautiful trio on the anniversary of Abetti’s birth about a half-hour before dawn!

Ready tonight for a new direction in observing? Then look no further than the tail of the Scorpion, and get ready to head south, then north. The Summer Milky Way is upon us! Let’s start with a ‘‘bright star and globular cluster’’ view. Some of the easiest studies to find are ones residing in the same field as bright, recognizable stars. And, some the most difficult things to observe in the night sky are—you guessed it—faint studies lying near overwhelmingly bright stars! But there are compromises. . .

Less than 30 east of 3.3-magnitude G Scorpii (the tail star of the Scorpion) is 7.4-magnitude globular cluster NGC 6441 (RA 17 50 12 Dec -37 03 03). This 38,000-light-year-distant compact cluster is about 13,000 light-years from the galactic core. It was first noted from southeastern Australia in 1826 by James Dunlop. Around 2.5 degrees northeast of G Scorpii (and NGC 6441) is another interesting deep-sky twosome—bright open cluster M7 and faint globular NGC6453. M7 (RA 17 53 51 Dec -34 47 34) was first recorded as a glowing region of faint stars by Ptolemy, circa 130 BC.

Located 800 light-years away, the cluster includes more than half a dozen 6th magnitude stars. It is easily resolved with the least amount of optical aid, and as many as 80 stars can be seen in a small telescope. Now head northeast, and the faint haze of the 31,000-light-year-distant globular cluster NGC 6453 (RA 17 50 51 Dec -34 35 59) will reveal itself to mid- and large-sized scopes. Like NGC 6441, this globular was discovered from the Southern Hemisphere, in this case by John Herschel on June 8, 1837, while he was observing from the Cape of Good Hope in South Africa.

Saturday, June 20, 2009 – In the predawn hours, we welcome the ‘‘shooting stars’’ as we pass through another portion of the Ophiuchid meteor stream. The radiant for this pass lies nearer Sagittarius, and the fall rate varies from 8 to 20 per hour, but the Ophiuchids can sometimes produce more than expected! But getting up early to watch a meteor shower has even more perks on this date…

Before day breaks, enjoy the ‘‘Old Moon in the New Moon’s Arm’’ as it heads toward a later occultation of the Pleiades. Look up higher yet and enjoy the fine conjunction of Mars and Venus as they pair together and overhead for the bright visage of Jupiter. Perhaps the sky acknowledges the 1966 passing of Georges Lemaitre on this date? Lemaitre researched cosmic rays and the three-body problem and in 1927 formulated the Big Bang theory using Einstein’s theories.

Tonight locate Lyra’s southernmost pair of stars—Beta and Gamma—for the Ring Nebula (RA 18 53 35 Dec +33 01 42). Discovered by Antoine Darquier in 1779, the Ring was cataloged later that year by Charles Messier as M57. In binoculars, it appears slightly larger than a star, but cannot be focused to a sharp point. Through a modest telescope, and even at low power, M57 turns into a glowing, elongated donut against a wonderful stellar backdrop. How you see the 1,400 light-year distant ‘‘King of the Rings’’ on any given night is highly subject to conditions. As aperture and power increase, so do details. It’s not impossible to see braiding in the nebula’s structure with scopes as small as 8’’ on a fine night, or to pick up the faint 13th magnitude star caught on the edge in even smaller apertures.

Like many planetary nebulae, seeing the central illuminating star is considered the ultimate in celestial viewing. This ‘‘shy friend’’ is a peculiar blue dwarf, which gives off a continuous spectrum and might be variable. At times, this near 15th magnitude star can be seen with ease through a 12.5’’ telescope, yet remains elusive to 31’’ in aperture a few weeks later. Can you spot faint IC 1296, which floats majestically nearby?

Sunday, June 21, 2009 – Wake up, sleepyheads. The last of the very fine conjunctions is about to end and you don’t want to miss it!

If you’re out before dawn, look for Mercury a little more than 6 degrees south of the Moon. No luck spotting it? Try binoculars. Mercury is only about 3 degrees north of red Aldebaran!

Summer solstice occurs today, but what exactly is it? A solstice is nothing more than an astronomical term for the moment when one hemisphere of Earth is tilted the most toward the Sun. Today, the Sun is about 24 degrees above the celestial equator—its highest point of the year. Summer solstice is also the day of the year with the longest period of daylight—and the shortest of night; this occurs around 6 months from now for the Southern Hemisphere.

Today is also the anniversary of the 1863 birth of Maximilian Franz Joseph Cornelius Wolf. Wolf used wide-field photography to study the Milky Way, and statistical treatment of star counts to prove the existence of clouds of dark matter. Wolf was one the first to prove spiral nebulae contained star-like spectra, and he introduced photography to help discover hundreds of asteroids!

Dark skies continue tonight, and so we’ll continue following the great expanse of the Summer Milky Way. Our first stop will be the Butterfly Cluster—M6 (RA 17 40 20 Dec -32 15 15). About the size of the Full Moon, this scattering of 7–12th magnitude stars looks like its namesake. The ‘‘wings’’ of M6 are easily seen as two lobes east and west of the cluster’s main body. Around 75 blue and blue/white stars are visible at low power.

Want more? Head northeast a little more than 1 degree to reveal the expansive, 5.5-magnitude open cluster NGC 6383. Continue to sweep west at low power to find what might be expected as a very faint sheen of stars—9th magnitude NGC 6374. What’s that? You can’t find it? Then you’ve just learned an invaluable lesson. Some things in J.L.E. Dreyer’s catalogue simply don’t exist!

But we exist, don’t we fellow SkyWatchers? You betcha’. And what a terrific weekend we had together!

The week’s awesome images are (in order of appearance): Antonio Abetti (historical image), M7 (credit—Burrell Schmidt/NOAO/AURA/NSF), Georges Lemaitre and Albert Einstein (historical image), M57 and IC 1296 (credit—Palomar Observatory, courtesy of Caltech), Max Wolf (historical image) and M6 (credit—Nigel Sharp, Mark Hanna, REU program/NOAO/AURA/NSF). We thank you all so much!

Greetings, fellow SkyWatchers! Are you ready for a great weekend? Then it’s time to do some challenging studies as we take on one of the most difficult globular clusters in the sky – Palomar 5. Need something you can spot with your eyes or binoculars? Then try the planet Mercury… But get up early! Maybe a weekend meteor shower that’s known for spitting out bright bolides is more to your liking… Still feeling challenged? Then let’s try our hand at some Herschel studies and blow some dust off the galaxies! Time to get out the scopes and the star charts and I’ll see you in the back yard.

Friday, June 12, 2009 – Today, remember the 1843 birth of Sir David Gill on this date, who took measurements of solar and stellar parallax, computed the distances of the Sun and other stars from Earth, and was first to use photography in mapping the heavens. To determine parallaxes, Gill perfected the heliometer, a telescope that uses a split image to measure the angular separation of celestial bodies. He later redetermined the solar parallax with such precision that almanacs used his value as late as 1968!

Completing astronomical projects is very challenging, and tonight we’ll hunt down a difficult globular cluster study by using M5 as a guide. Palomar 5 is by no stretch of the imagination easy. For GoTo systems, aiming is easy, but for large telescopes, starhopping instructions are critical. From M5 drop south for double 5 Serpens, and again south and slightly west for another, fainter double. Don’t confuse it with eastern 6 Serpens. A half degree west you’ll encounter an 8th magnitude star, with 7th magnitude 4 Serpens a half degree south. Continue south another half degree, for a triangle of 9th magnitude stars. The southern apex star is home to Palomar 5 (RA 15 16 05 Dec +00 06 41).

Discovered by Walter Baade in 1950, this 11.7 magnitude, Class XII globular was first believed to be a dwarf elliptical galaxy, possibly a member of our Local Group. Later studies showed Palomar 5 to be a globular cluster but one being ripped apart by the tidal forces of the Milky Way—at 60,000 light-years from the galactic center! Palomar 5’s members are escaping, leaving trails spanning 13,000 light years – a several billion year process. Telescopes of 6’’ can distinguish a few individual members northwest of the 9th magnitude marker star, but even ones as large as 31’’ fail to show more than a handful of resolvable stars. This may be the toughest locating job you’ll ever tackle, but be sure to make a quick sketch of the region to complete your studies. Good luck!

Saturday, June 13, 2009 – Before dawn, Mercury reaches its highest morning elevation, and you’ll find the asteroid Psyche less than half a degree north of the Moon. Look a finger-width south of Luna, and you’ll see Neptune and Jupiter separated by less than a degree! Perhaps they’re saluting the 1831 birth on this date of James Clerk Maxwell? Maxwell calculated that the speed of propagation of an electromagnetic field is approximately the speed of light, thereby inferring that light is an electromagnetic phenomenon. Born on the same day but 28 years before him was Thomas Young, who had demonstrated the wave nature of light.

For us, tonight’s light waves will be from Herschel II.76, also known as NGC 5970. Begin by identifying Beta and Delta Serpentis, and look for finderscope Chi between them. Less than a degree southwest, you will see a similar-magnitude double star. Hop about one-third degree northwest, and you’ll find the galaxy just a fraction southwest of a 7th magnitude star (RA 15 38 302 Dec +12 11 11).

NGC 5970 isn’t particularly easy for smaller scopes (even near 11th magnitude), because of its low surface brightness, but its structure makes it a distant cousin of the Milky Way. At 105 million light year-distant, it’s no great surprise we see it as faint, for its light left around the time the dinosaurs ruled Earth. Stretching across 85,000 light-years of space, the nuclear region, obscuring dust regions, and the stellar population of this grand spiral have been extensively studied. And—like us—it is also part of its own Local Group. Although smaller telescopes will make out a slightly elongated mist, in mid-to-large apertures NGC 5970 will appear oval-shaped with a bright core and evidence of a central bar. Although the edges of the galaxy seem well-defined, look closely at the narrower ends, where material seems more wispy. Seen averted, the nucleus will sometimes take on a stellar appearance yet lose this property with direct vision. Be sure to mark your Herschel notes on this one!

Sunday, June 14, 2009 – As the new hours of the day begin and you wait on dawn, keep watch for the peak of the Ophiuchid meteor shower with the radiant near Scorpius. The fall rate is poor, with only 3 per hour, but fast moving bolides are common. This meteor stream will last for 25 days. While you’re out, see if you can spot Mercury! What planet is the Moon near now?

Tonight, let’s go south in Libra and have a look at the galaxy pairing NGC 5903 and NGC 5898.

You’ll find these about 3 degrees northeast of Sigma, and just north of a pair of 7th magnitude stars (RA 15 18 36 Dec -24 04 05). Although northernmost NGC 5903 seems to be nothing more than a faint elliptical with a brighter concentration toward the center and an almost identical elliptical—NGC 5898—to the southwest, you’re probably asking yourself. . .why the big deal over two small ellipticals?

First off, NGC 5903 is Herschel III.139 and NGC 5898 is Herschel III.138—two more to add to your studies. And second? The Very Large Array has studied this galaxy pair in the spectral line of neutral hydrogen. The brighter of the pair, NGC 5898, shows evidence of ionized gas that has been collected from outside its galactic realm, while NGC 5903 seems to be running streamers of material toward it. A double-galaxy, double-accretion event!

But there’s more. . .

Look to the southeast, and you’ll double your pleasure and double your fun as you discover two double stars instead of just one! Sometimes we overlook field stars for reasons of study, but don’t do it tonight! Even mid-sized telescopes can easily reveal this twin pair of galaxies sharing ‘‘their stuff,’’ as well as a pair of double stars in the same low power field of view. (Psst. . .slim and dim MCG 043607 and quasar 1514-241 are also here!) Ain’t it grand?

Until next week? Stay challenged and you’ll always stay interested!

This week’s awesome images are (in order of appearance): Sir David Gill (historical image), Palomar 5 (credit—Palomar Observatory, courtesy of Caltech), James Clerk Maxwell (historical image), NGC 5970 (credit—Palomar Observatory, courtesy of Caltech) and NGC 5903 and NGC 5898 field (credit—Palomar Observatory, courtesy of Caltech). We thank you so much!