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Designations:
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M74, NGC 628, The Phantom Galaxy
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Object Type:
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Spiral Galaxy
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Constellation:
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Pisces
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1 hr 36.7 min
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+15° 47 min
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9.4 (SB 14.4)
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Size:
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10.5 X 9.5 arcminutes
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Distance:
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32 million light years
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Discoverer:
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Pierre Mechain, 1780
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Blazing with the light of 40 billion suns, flinging spiral arms across 97,000
light years
of space, M74 is a prima donna among open-face spiral galaxies. At least, that is how it comes
across in long-exposure photographs taken through large telescopes. In small telescopes, it is more like a
phantom, which is the nickname given to it by Steven James O'Meara in the book
"The Messier Objects".
No object in the Messier catalogue has proven more troublesome, more elusive, more provocative to amateur
astronomers than this giant spiral. The problem is that the
galaxy's
large apparent size (10'.5) and very low
surface brightness require a very dark sky for it to be seen well, if at all! Mechain was right on the mark
when he said, "This nebula... is quite broad, very dim, and extremely difficult to observe; it may be
distinguished more accurately during fine frosts. "The fine frosts he refers to, I am sure, are those
incredibly transparent evenings following the passage of a cold front, when the night sky is free from
moisture and atmospheric contaminants, and the stars can be seen with crystal clarity away from city lights.
On these nights you have the best chance to see dim and diffuse objects.
Stephen James O'Meara searched for M74 many nights with Harvard Observatory's 9-inch refractor without success. The fact is, so large an aperture under less-than-perfect skies doomed his quest before it even started. It's best to use a small-aperture instrument, low power, and a wide field of view on the finest of nights. Locating the field is easy. Look about 1½° east-northeast of 3.6- magnitude Eta (η) Piscium. From dark skies 23 x shows M74 as an obvious but pale disk of uniform light. The longer you look, the more detail you should see. Watch how the core slowly materializes into a compact orb punctuated by a pinpoint of light. With averted vision a diffuse outer skirt also takes shape. Jones believed that M74 could not stand anything but low power, but I disagree. If you can make out the galaxy's inner core, then that is the time to change to higher power. The core itself is mottled with the light of many dim stars, which emerge only with high powers. It is this chance alignment of field stars projected against the nucleus that obviously caused John Herschel to mistake M74 for a globular cluster which in turn led Dreyer to list it as a globular in the New General Catalogue. |
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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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11 X 10-minute exposures for luminance, 3 X 10-minute exposures for red, green, and blue (200 minutes total exposure)
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Location:
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Twin Lakes Star Party, Western Kentucky
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Software:
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CCDSoft for image acquisition, processed with CCDStack and Photoshop CS2
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