Sky and Telescope - May 2012 - (Page 58)
OBSERVING
Deep-Sky Wonders
Left: NGC 4516 is a spiral with a pronounced S-shaped bar. Center: IC 3476 is an irregular galaxy whose blue stars suggest ongoing starburst activity. Right: NGC 4571 is an unusual ringed spiral galaxy.
the accepted solution to this puzzle, first published in this magazine’s Letters column for December 1969. William C. Williams found that NGC 4548 fits Messier’s description and position for M91 if you assume that Messier mixed up which object he’d used as his reference point. Thus Messier’s offsets should be applied to M88, not M58. The little galaxy NGC 4516 sits one-third of the way from M88 to M91 and 8′ north of an imaginary line connecting them. With my 105mm scope at 87×, I can see NGC 4516 intermittently with averted vision as a very small glow elongated north-south. (Averted vision is the practice of looking a bit off to one side of a faint object to allow its light to fall on a more sensitive area of your eye’s retina.) The view through my 10-inch reflector at 192× is fascinating. At first glance, I was astonished when the galaxy’s tilt seemed to change with averted vision. A more careful look showed a bright region about 1′ long and one-quarter as wide, tipped west of north, that spans a slender, larger oval running nearly north-south. Only the former stood out with direct vision. The bright area is lovely, and consists of a small core with a distinct nucleus at the center of a shallow S curve. Averted vision wraps it all in a delicate cocoon. Let’s drop 24′ south-southeast from M88 to a northsouth pair of 12th-magnitude stars 2.7′ apart. The intriguing galaxy IC 3476 rests 4.4′ east of the northern star. It’s readily visible in my 105-mm refractor at 87× as a hazy blot about 40″ across. In the 10-inch scope at 192×, three faint suns join the 12th-magnitude pair to outline
a candle snuffer ready to put out the light of IC 3476. The galaxy displays a lumpy brightness distribution and peculiar shape. IC 3476 is about 40″ wide at its northeastern end and tapers down toward the southwest, giving it a candle-flame profile 1¼′ long. The wide end contains a relatively large, blotchy, bright area, and some additional clumpy enhancements line the galaxy’s southeastern side. Strange little IC 3476 has been assigned a morphological type of IB(s)m — a barred, Magellanic-type irregular galaxy with traces of spiral structure. IC 3476 surprised astronomers with a supernova in 1970. Our final target is NGC 4571, found 28′ southeast of M91 with a 9th-magnitude star guarding its northeastern edge. The galaxy appears roundish with a small brighter core in the 105-mm scope at 87×. Its low-surface-brightness halo improves with averted vision and is roughly 2′ to 2½′ across. Although NGC 4571 is more obvious in my 10-inch scope, it discloses no further secrets. NGC 4571 is an unusual galaxy of type SA(r)c. Its fleecy spiral arms reach inward to a well-defined ring that closely circles the galaxy’s core. Such ring structure is rare in a late-type spiral galaxy, that is, one that exhibits a small central bulge and loosely structured arms with prominent condensations. All these wonderful world-isles dwell in the core of the vast Virgo Cluster, possessing whole heavens within themselves that have long inspired the wondering skygazer’s amazement. ✦
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SLOAN DIGITAL SKY SURVEY (3)
Table of Contents for the Digital Edition of Sky and Telescope - May 2012
Sky and Telescope - May 2012
Table of Contents
Spectrum
Letters
75, 50 & 25 Years Ago
News Notes
Saturn’s Raging Superstorm
Stars Above, Earth Below: Astronomy in National Parks
The Remarkable Case of Comet Lovejoy
In This Section
May’s Sky at a Glance
Binocular Highlight
Planetary Almanac
Northern Hemisphere’s Sky
Sun, Moon, and Planets
Celestial Calendar
Exploring the Solar System
Deep-Sky Wonders
Going Deep
S&T Test Report
New Product Showcase
Telescope Workshop
Planetary Imaging with Your DSLR Camera
Gallery
Focal Point
Sky and Telescope - May 2012
Sky and Telescope - May 2012 - (Page Intro)
Sky and Telescope - May 2012 - Sky and Telescope - May 2012 (Page Cover1)
Sky and Telescope - May 2012 - Sky and Telescope - May 2012 (Page Cover2)
Sky and Telescope - May 2012 - Sky and Telescope - May 2012 (Page 3)
Sky and Telescope - May 2012 - Table of Contents (Page 4)
Sky and Telescope - May 2012 - Table of Contents (Page 5)
Sky and Telescope - May 2012 - Spectrum (Page 6)
Sky and Telescope - May 2012 - Spectrum (Page 7)
Sky and Telescope - May 2012 - Letters (Page 8)
Sky and Telescope - May 2012 - Letters (Page 9)
Sky and Telescope - May 2012 - 75, 50 & 25 Years Ago (Page 10)
Sky and Telescope - May 2012 - 75, 50 & 25 Years Ago (Page 11)
Sky and Telescope - May 2012 - News Notes (Page 12)
Sky and Telescope - May 2012 - News Notes (Page 13)
Sky and Telescope - May 2012 - News Notes (Page 14)
Sky and Telescope - May 2012 - News Notes (Page 15)
Sky and Telescope - May 2012 - News Notes (Page 16)
Sky and Telescope - May 2012 - News Notes (Page 17)
Sky and Telescope - May 2012 - News Notes (Page 18)
Sky and Telescope - May 2012 - News Notes (Page 19)
Sky and Telescope - May 2012 - Saturn’s Raging Superstorm (Page 20)
Sky and Telescope - May 2012 - Saturn’s Raging Superstorm (Page 21)
Sky and Telescope - May 2012 - Saturn’s Raging Superstorm (Page 22)
Sky and Telescope - May 2012 - Saturn’s Raging Superstorm (Page 23)
Sky and Telescope - May 2012 - Saturn’s Raging Superstorm (Page 24)
Sky and Telescope - May 2012 - Saturn’s Raging Superstorm (Page 25)
Sky and Telescope - May 2012 - Stars Above, Earth Below: Astronomy in National Parks (Page 26)
Sky and Telescope - May 2012 - Stars Above, Earth Below: Astronomy in National Parks (Page 27)
Sky and Telescope - May 2012 - Stars Above, Earth Below: Astronomy in National Parks (Page 28)
Sky and Telescope - May 2012 - Stars Above, Earth Below: Astronomy in National Parks (Page 29)
Sky and Telescope - May 2012 - Stars Above, Earth Below: Astronomy in National Parks (Page 30)
Sky and Telescope - May 2012 - Stars Above, Earth Below: Astronomy in National Parks (Page 31)
Sky and Telescope - May 2012 - Stars Above, Earth Below: Astronomy in National Parks (Page 32)
Sky and Telescope - May 2012 - Stars Above, Earth Below: Astronomy in National Parks (Page 33)
Sky and Telescope - May 2012 - Stars Above, Earth Below: Astronomy in National Parks (Page 34)
Sky and Telescope - May 2012 - Stars Above, Earth Below: Astronomy in National Parks (Page 35)
Sky and Telescope - May 2012 - The Remarkable Case of Comet Lovejoy (Page 36)
Sky and Telescope - May 2012 - The Remarkable Case of Comet Lovejoy (Page 37)
Sky and Telescope - May 2012 - The Remarkable Case of Comet Lovejoy (Page 38)
Sky and Telescope - May 2012 - The Remarkable Case of Comet Lovejoy (Page 39)
Sky and Telescope - May 2012 - The Remarkable Case of Comet Lovejoy (Page 40)
Sky and Telescope - May 2012 - The Remarkable Case of Comet Lovejoy (Page 41)
Sky and Telescope - May 2012 - The Remarkable Case of Comet Lovejoy (Page 42)
Sky and Telescope - May 2012 - In This Section (Page 43)
Sky and Telescope - May 2012 - May’s Sky at a Glance (Page 44)
Sky and Telescope - May 2012 - Binocular Highlight (Page 45)
Sky and Telescope - May 2012 - Planetary Almanac (Page 46)
Sky and Telescope - May 2012 - Northern Hemisphere’s Sky (Page 47)
Sky and Telescope - May 2012 - Sun, Moon, and Planets (Page 48)
Sky and Telescope - May 2012 - Sun, Moon, and Planets (Page 49)
Sky and Telescope - May 2012 - Celestial Calendar (Page 50)
Sky and Telescope - May 2012 - Celestial Calendar (Page 51)
Sky and Telescope - May 2012 - Celestial Calendar (Page 52)
Sky and Telescope - May 2012 - Celestial Calendar (Page 53)
Sky and Telescope - May 2012 - Exploring the Solar System (Page 54)
Sky and Telescope - May 2012 - Exploring the Solar System (Page 55)
Sky and Telescope - May 2012 - Deep-Sky Wonders (Page 56)
Sky and Telescope - May 2012 - Deep-Sky Wonders (Page 57)
Sky and Telescope - May 2012 - Deep-Sky Wonders (Page 58)
Sky and Telescope - May 2012 - Deep-Sky Wonders (Page 59)
Sky and Telescope - May 2012 - Going Deep (Page 60)
Sky and Telescope - May 2012 - Going Deep (Page 61)
Sky and Telescope - May 2012 - Going Deep (Page 62)
Sky and Telescope - May 2012 - Going Deep (Page 63)
Sky and Telescope - May 2012 - S&T Test Report (Page 64)
Sky and Telescope - May 2012 - S&T Test Report (Page 65)
Sky and Telescope - May 2012 - S&T Test Report (Page 66)
Sky and Telescope - May 2012 - S&T Test Report (Page 67)
Sky and Telescope - May 2012 - New Product Showcase (Page 68)
Sky and Telescope - May 2012 - New Product Showcase (Page 69)
Sky and Telescope - May 2012 - Telescope Workshop (Page 70)
Sky and Telescope - May 2012 - Telescope Workshop (Page 71)
Sky and Telescope - May 2012 - Planetary Imaging with Your DSLR Camera (Page 72)
Sky and Telescope - May 2012 - Planetary Imaging with Your DSLR Camera (Page 73)
Sky and Telescope - May 2012 - Planetary Imaging with Your DSLR Camera (Page 74)
Sky and Telescope - May 2012 - Planetary Imaging with Your DSLR Camera (Page 75)
Sky and Telescope - May 2012 - Gallery (Page 76)
Sky and Telescope - May 2012 - Gallery (Page 77)
Sky and Telescope - May 2012 - Gallery (Page 78)
Sky and Telescope - May 2012 - Gallery (Page 79)
Sky and Telescope - May 2012 - Gallery (Page 80)
Sky and Telescope - May 2012 - Gallery (Page 81)
Sky and Telescope - May 2012 - Gallery (Page 82)
Sky and Telescope - May 2012 - Gallery (Page 83)
Sky and Telescope - May 2012 - Gallery (Page 84)
Sky and Telescope - May 2012 - Gallery (Page 85)
Sky and Telescope - May 2012 - Focal Point (Page 86)
Sky and Telescope - May 2012 - Focal Point (Page Cover3)
Sky and Telescope - May 2012 - Focal Point (Page Cover4)
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