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Designations:
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M97, NGC 3587
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Object Type:
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Constellation:
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Ursa Major
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11 hr 14.8 min
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+55° 1 min
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9.9
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Size:
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2.2 arcminutes
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Distance:
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1630 light years
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Discoverer:
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Pierre Mechain, 1781
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This distinctive
planetary nebula,
so strongly reminiscent of the face
of an owl (at least in photographs), is a real challenge for small telescopes because its faint light
is spread over an are roughly five times the size of Jupiter's apparent disk. Thus, to see the Owl
Nebula well, one needs to be under a dark sky. The glow will probably elude anyone using a telescope
with an aperture smaller than 6 inches and one needs at least a 12-inch instrument to see the "eyes" of
the Owl. M97 earned the "Owl" moniker from a sketch made by Rosse in 1848, who through his 72-inch
telescope spied the two dark holes that look like eyes peering spookily from a round face. The Owl
is certainly challenging, especially from a city.
M97 is one of the more complex planetary nebulae. Its appearance has been interpreted as that of a cylindrical torus shell (or globe without poles), viewed oblique, so that the projected matter-poor ends of the cylinder correspond to the owl's eyes. This shell is enveloped by a fainter nebula of lower ionization. The mass of the nebula has been estimated to amount 0.15 solar masses, while the 16 mag central star is believed to be of about 0.7 solar masses. Its dynamical age is about 6,000 years. (from Stephen J. Hynes, planetary nebulae). |
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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
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Exposures:
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12 7-minute exposures (84 minutes total)
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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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