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Galaxy’s core region.
This week will be an exciting one as we return the the Galaxy hunt and view the Cosmos through the eyes of Pioneer. The excitement heats up as the Ophiuchid meteor shower comes along and Mars mixes it up with the Beehive. Still not enough? Then hang on as the June Lyrids streak across the night and Saturn and Mars team up to join Mercury! It’s going to be one great week to enjoy the night, because... Here’s what’s up!
Before you read this week’s What’s Up, I just wanted to remind you that What’s Up - 365 Days of Skywatching now has a blog of its own. You can access it by going to http://www.astrowhatsup.com
Now, on to the week.
Monday, June 12 - Before the Moon rises tonight, let’s visit Cor Caroli and "La Superba" and split the distance between them to find the spiral Galaxy M94. At magnitude 8.2, this expansive galaxy’s core region is very prominent, yet smaller scopes will have difficulty making out much structure due to low surface brightness. Mid-to-large aperture will pick up on a tightly wound spiral structure with hints of obstruction by dark dust at the galaxy’s edges.
M94 was discovered by Pierre Méchain on March 22, 1781. Two nights later it was re-observed and catalogued by Charles Messier. Current distance estimates vary, but 15 million light-years is a given value. Like M81 in Ursa Major, and M83 in Hydra, M94 is a small spiral - well-formed, but far less massive than our own.
Tuesday, June 13 - Today in 1983, Pioneer 10 became the first manmade object to leave the solar system. Sailing in the general direction of Aldebaran for 68 light-years, what wonders will it see?
As Pioneer 10 approaches Aldebaran it might look back on a faint 6th magnitude yellow star - our Sun - poised against the backdrop of a constellation now visible after skydark - Ophiuchus. Within just a few degrees north of our Sun would appear a "ball of stars" - M107. Let’s get our own Pioneer 10 view tonight...
Center your scope or binoculars on Antares (Alpha Scorpii) and move north past a jagged line of four fainter stars - Rho, Psi, Chi, and Phi Ophiuchi. Just two degrees north of Phi is 5.8 magnitude SAO 159948. Imagine this star replaced by our own Sun in the night sky. Using binoculars, finderscope, or low power telescope - frame this "Sun" in the same field with 8.1 magnitude globular cluster M107. That’s what Pioneer 10 will view from Aldebaran - 2 million years from tonight!
Although the Moon will soon be along, keep watch for the peak of the Ophiuchid meteor shower with the radiant near the rising Scorpio. The fall rate is poor - with only 3 per hour - but fast moving bolides are common. The duration of this stream is 25 days.
Wednesday, June 14 - Tonight we have plenty of time for exploration. Let’s begin by locating a globular cluster in the southern constellation Lupus - "The Wolf." You’ll find NGC 5986 around three finger-widths south of Psi 1 and 2 in the same field with SAO 206887.
At 34,000 light-years away, this globular cluster is a Class VII, and bright enough to be seen with binoculars. Despite being some 16,000 light-years from the galactic core, NGC 5986 is already beginning to feel the powerful pull of gravity tugging away a stream of stars and distorting its globular shape.
For large scopes, let’s go Galaxy hunting. Locate Arcturus and Spica and split the distance between them to roughly locate a pair of galaxies in the same low-power field. NGC 5363 is a small, and relatively bright, elliptical Galaxy - which will appear as a pale oval. To its south is NGC 5364, which is a larger, but fainter, slightly-tilted spiral. Look for an intense stellar core. Photographically, NGC 5364 is one of the loveliest galaxies in the Coma-Virgo cluster.
Thursday, June 15 - Celestial Scenery Alert! Tonight, Mars will pass directly in front of the Beehive Cluster - M44. Be sure to at least have a look! While Mars will be far brighter than the cluster’s stars, a dark sky site will show them both without optical aid - but be sure to have a look with binoculars or scopes! For all you photographers out there - this would make an outstanding "sky shot"!
Not enough? Mercury will also be moving into the evening sky not far from Saturn and Mars.
With early evening dark skies, let’s go after a cluster of galaxies southwest of Iota Draconis. To locate the field begin at a visible star (SAO 29407) about half a fist width away. Centering on it, shift a little more than a degree due north to turn up the brightest Galaxy in this group - NGC 5866 - otherwise known as M102. For those working on their Astronomical League Messier list, NGC 5866 is the accepted designation for a "messy mistake."
Tenth magnitude "M102″ is both bright and large enough to have been seen by Méchain and Messier, but we know there are dozens of such galaxies throughout the spring sky. Despite the mistake, it’s clear this 40 million light-year distant spiral is a superb example of an edge on - even in modest-sized scopes. At mid-size, look for a faint halo surrounding a bright core region and dark lane bisecting the Galaxy to the southeast. Large instruments will detect faint spiral arms extending visibly outward - considerably further than expected from a spindle-shaped edge-on.
Continuing north another 2 degrees and slightly east in a low power field, will reveal 11.5 magnitude NGC 5879. This is a slightly tilted spiral Galaxy with wispy, curved extensions. A little more than 1 degree east of NGC 5879 is a very thin, but brighter, 10.4 magnitude edge-on: NGC 5907. Sometimes called the "Splinter" galaxy, it’s the second brightest member of the NGC 5866 group.
Less than a degree due south of the Splinter Galaxy is a faint pair - NGC 5905 and NGC 5908 - which are barely visible in modest telescopes. At magnitude 11.9, NGC 5908 resembles a smaller, dimmer version of NGC 5866. Around 12 arc minutes due west is 12.0 magnitude NGC 5905. It might appear as a faint, edge-on spiral, but it’s an illusion caused by a barred spiral.
Friday, June 16 - Well before dawn, the June Lyrid meteor shower peaks. The Moon is closest to the Earth right now, but even if it were not, it would still dim the view. Look for the radiant near bright Vega where you may see up to 15 faint blue meteors per hour from this branch of the May Lyrid meteor stream.
Today in 1963, Valentina Tereshkova, aboard Soviet Vostok 6, became the first woman in space. Her solo flight remains unique to this day. Twenty years later, on the 18th, Sally Ride became the first American woman in orbit - aboard Space Shuttle Challenger.
Tonight let’s take a "flight through space" and visit the night sky. All it takes is a little imagination and the ability to keep looking up!
Let’s revisit magnificent globular cluster M5. This fifth brightest globular cluster in the sky is considered one of the most ancient at 13 billion years old. Located further away from the dusty galactic center, resolution explodes as we move up in aperture. Easily seen as a round ball of unresolved stars in binoculars, small scopes begin to pick up individual stellar points at higher magnifications. Careful attention shows that M5 is not perfectly round. Its brightest 11th and 12th magnitude stars actually are randomly distributed but seem to array themselves in great arcs.
Saturday, June 17 - Celestial scenery alert! Head outside just after sunset and look west. Saturn and Mars are now slightly more than a half degree apart. Don’t wait too late to view, for the pair will soon set!
Take the time to really enjoy the "Great Cluster" in Hercules tonight - M13. Only rivaled by M5 as the grandest globular cluster in the northern hemisphere night sky, even modest scopes will see M13 is "stellar" in nature. Mid-aperture will reveal dozens of 12th magnitude stars taking up positions in great arcs surrounding an intensely condensed core - giving this immaculate cluster the look of a scarab beetle with hooked mandibles. For large scopes, something extraordinary occurs - up to five low star density zones appear - giving the cluster a visibly mottled look.
Now head north-northwest just off M13’s edge to find 11.6 magnitude Galaxy NGC 6207. Visible through mid-sized scopes, this tilted spiral can be a challenge. For something even more difficult, try 12th magnitude IC 4615 - one degree southwest of M13.
Sunday, June 18 - Thinking of donuts? Then here’s your chance to observe their celestial equivalent. Look between the southern-most pair of stars in Lyra, Beta and Gamma, for the "Ring Nebula!"
First discovered by Astronomer Antoine Darquier in 1779, the "Ring" was cataloged later that year by Charles Messier as M57. The accepted distance to this unusual structure is around 1,400 light-years. In binoculars it appears slightly larger than a star, yet it 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 "King of the Rings" on any given night is highly subject to conditions. As aperture and power increase, so do details. It is not impossible to see braiding in the nebula 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 nebula, 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 remain elusive to 31″ in aperture a few weeks later. No matter what details you see, capture "the Ring" tonight. You’ll be glad you did.
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