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By Glenn Chaple for the LVAS

NGC 1003– Spiral Galaxy in Perseus Magnitude: 11.5 Size: 5.5’ X 2.0’

When William Herschel conducted his systematic sky surveys during the latter part of the 18th century, he placed his deep sky finds into 8 categories, or classes. Class I through III included nebulosities of varying degrees of visibility, class I being the brightest. Although the Herschel Catalog designations have been replaced by the New General Catalog (NGC) numbers, they still serve as guides to selecting “faint fuzzies” appropriate for a specific aperture telescope. Consider the spiral galaxy NGC 1003 in Perseus. When Herschel came upon it in the autumn of 1784, he catalogued it twice – as number 238 in Class II (Faint Nebulae) and as number 198 in Class III (Very Faint Nebulae). In either case, this is not a target you’d select for a small backyard scope.

George Kepple and Glen Sanner’s Night Sky Observing Guide provide descriptions of deep-sky objects by aperture ranges of 4-6, 8-10, 12-14, 16-18 and(occasionally) 20-22 inches. The smallest aperture for which a visual description of NGC 1003 is given is for the 12-14-inch range. In the Observing Handbook and Catalogue of Deep-Sky Objects, authors Christian Luginbuhl and Brian Skiff describe it as “easily visible in 15 cm (8 inches). Can this galaxy be glimpsed with smaller apertures? To capture NGC 1003 with a 4 – 6-inch scope will require extremely dark sky conditions and a well-trained, dark-adapted eye.

Telescopically, NGC 1003 appears as a faint east-west smudge, concentrated towards the center. Measurements hint at a distance of 33 light years, which translates to a true diameter of 54,000 light years. NGC 1003 is located about a degree northwest of the 5th magnitude star 12 Persei. It’s interesting to note that when constellation boundaries were formally defined by the International Astronomical Union in 1930, the borderline between Perseus and Andromeda cut through the western part of NGC 1003 – the galaxy literally resides in two constellations!

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