My first Magazine Sky & Telescope - 01.2019

Observing in the Park 7822 vdB 8 W I 31 Ced 214 3 3053 Y CASSIOPEIA Tr 3 3 163 IC 289 IC 1871 Cr 34 1027 Cr 33 E IC 1795 896 IC 1805 Mrk 6 IC 1848 884 H 957 Tr 2 DM PERSEUS 9 869 KK 9 K 637 559 7790 12 225 654 663 659 Stock 2 6 381 V770 M103 IC 63 Ruchbah D 436 F Sh2-188 Double Cluster 457 V465 (c) 136 129 IC 59 Caph G U 2 IC 10 TV vdB 1 U 1 3 3062 H Schedar 281 T If you sweep from Epsilon (ε) at the easternmost end of Cassiopeia’s W through Delta (δ) and continue half again as far, bending slightly to the south, you land atop 5.0-magni- tude Phi (φ) Cassiopeiae. It’s the brightest star that appears within the open cluster NGC 457, though it’s probably an unrelated foreground star. Many people consider this the most attractive cluster in the constellation because its stars form a striking stick ﬁ gure, with Phi and 7.0-magnitude HD 7902 as the much brighter eyes. The ﬁ gure has many popular names, including the Owl, the E.T. (after Steven Spielberg’s ﬁ lm of the same name), and the Kachina Doll Cluster. I can see all the important stars in my 130-mm scope at 27×, but you might need more magniﬁ - cation if you have a smaller telescope. A remarkable ﬁ eld containing the open clusters M103, NGC 663, NGC 659, and NGC 654 lies east and northeast of Delta Cas. Under dark skies, my 130-mm reﬂ ector shows all four of these in the same ﬁ eld of view at 22×. But from the suburbs, NGC 654 and NGC 659 disappear completely at such low magniﬁ cations, and M103 becomes a shadow of its true self. Sadly, the high magniﬁ cations necessary to combat skyglow preclude the rich wide-ﬁ eld views that make dark-sky observing so enticing. At low power M103 appears to be just four medium-bright stars in a very tight formation reminiscent of a lower-case Greek lambda (λ). The southernmost and second-brightest of those, 8.2-magnitude HD 9365, is actually a foreground star. But when I use 81× in my 130-mm scope, I pick up another 64 JA N UA RY 2 019 • SK Y & TELESCOPE eight stars in the northern half of the cluster. Bigger scopes and darker skies show even more, revealing M103 to be a fairly rich, densely packed cluster. NGC 663 is by far the biggest and brightest of the four clusters, revealing a dozen stars at 22×, and at least twice as many at 81×. But for all its brightness, NGC 663 is some- what lacking in charm due to the fact that its stars are fairly loosely packed and don’t make any eye-catching patterns. Using averted vision at 27× I can just make out NGC 659 as a faint, unresolved blur ½° south-southwest of NGC 663, just off the tip of a prominent star triangle. Three or four stars twinkle intermittently through the haze when I raise the magniﬁ cation to 81×. The prominent reddish 7.3-magnitude star HD 10494 lies ¾° north-northwest of NGC 663, with NGC 654 just beyond. I ﬁ nd this cluster somewhat harder to make out at 27× than NGC 659, presumably because it’s camouﬂ aged by the glare of HD 10494. But at 81× NGC 654 becomes more prominent than NGC 659. Averted vision reveals a half dozen 11th-magnitude stars. Surprisingly, HD 10494 probably is a member of this cluster, despite the fact that it outshines the second-brightest star by a factor of 20. Such a big brightness gap implies that the star must be something special, and indeed spectros- copy shows that it’s a rare F-type supergiant. Supergiants are short-lived, so this in turn proves that NGC 654 must be quite young. Indeed, NGC 654 is about 14 million years old, compared to roughly 120 million years for the mature p TAKE THE ATLAS WITH YOU All the objects described in this article are plotted and labeled in Sky & Telescope’s Pocket Sky Atlas. Because it shows only the brightest deep-sky objects, the Pocket Sky Atlas is ideal for stargazers whose views are impaired by light pollution.

My first Magazine Sky & Telescope - 01.2019 | Page 66