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Designations:
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M56, NGC 6779
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Object Type:
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Constellation:
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Lyra
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19 hr 16.6 min
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+30° 11 min
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8.4
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Size:
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Distance:
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31,000 light years
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Discoverer:
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Messier, 1779
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What a perfect snowball M56 is, 7' across and shining at 8th
magnitude,
amid the blizzard of the Milky Way.
Actually the globular looks more like a dirty snowball, because
of its grayish pallor. The color is interesting, considering that so many other Messier globulars
display delicate pastel hues. Interstellar dust dims the cluster by about 0.2
magnitude.
In the low-power view a faint stream of stars flows from the south-east and drains into M56's foggy pool. The tiny, round glow (which is really 63 light years across) is punctuated by a 10th- magnitude star to its west. And a 5.8-magnitude, orange M2 star about ½° to the northeast adds some color. There's also a fine 8th- magnitude double about the same distance to the southwest. Moderate power starts to resolve the cluster, which immediately appears elongated north-south. In fact, the inner core is highly asymmetrical. With a thin fan of material to the south and nothing like it immediately opposite to the north, the innermost region of M56 is quite unique, looking like a light bulb or an exclamation mark. Interestingly, Mallas noted that unlike most other globulars, M56 does not have a bright core. And his drawing of the cluster shows a substantially large elliptical vacancy in the center. Jones reported that M56 has "no very marked central condensation," as did Burnham (almost verbatim). Skiff speaks of an irregularly round and broad concentration to the center, which corroborates what Smyth drew in his Cycle of Celestial Objects. High power reveals a strong dark lane separating the 11th- magnitude "central" star and the southern fan of mottled starlight. Meanwhile, don't miss out on enjoying the vast web of darkness surrounding M56 at 23x. It causes many neighboring regions to look as if the stars have been deposited there by the ebb and flow of some unseen galactic surf. |
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Telescope:
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Focal Length:
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1200 mm
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Mount:
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Camera
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Guider:
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SBIG AO-7 adaptive Optics Unit
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Exposures:
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9 10-minute exposures.
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Location:
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Cicero, IN
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Software:
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CCDSoft for image acquisition, processed with CCDStack and Photoshop CS2
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