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Designations:
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M51, NGC 5194
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Object Type:
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Spiral Galaxy
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Constellation:
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Canes Venatici
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13 hrs 29.9 min
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+47° 29.9 min
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8.4
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Size:
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11.2 X 6.9 arcminutes
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Distance:
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15 million light years
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Discoverer:
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Messier, 1773
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About 3½° SW from the Great Dipper, This is the famous "Whirlpool
Galaxy",
the first galaxy
found to show a spiral form. It was discovered by Charles Messier in October 1773, and the
intriguing spiral pattern was first detected by
Lord Rosse
with his giant 6-foot reflector at Parsonstown,
Ireland, in 1845. Rosse published his drawing of the object in 1850; it seems that he had observed the Galaxy
previously with a 3-foot telescope and had missed the spiral pattern. Sir John Herschel, with his 18-inch
reflector, had described a "very bright round nucleus surrounded at a distance by a luminous ring". The discover of
the spiral pattern aroused much interest, and was regarded by some 19th century students of cosmology as a
confirmation of
Laplace's Nebular Hypothesis.
Thus the "spiral nebulae" were at first thought to be new solar
systems in the process of formation, and it was not until 1923 that the question was settled with finality.
The spirals were now recognized as external galaxies, and the modern picture of the
universe
began to emerge.
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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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Exposures:
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17 12-minute exposures luminance (204 minutes) and 4 12-minute exposures for each color (144 Minutes). Total time 5-hour and 48 minutes
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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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Image Automation:
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