My first Magazine Sky & Telescope - 01.2019

JANUARY 2019 OBSERVING Deep-Sky Wonders by Sue French Meridian Observing Viewing is at its best when an object is at its highest in the night sky. T 54 JA N UA RY 2 019 • SK Y & TELESCOPE p NGC 869 and NGC 884, together known as the Double Cluster, are approximately the same age (14 million years old) and lie about the same distance (7,500 light-years) from Ea rth. These measurements suggest that the two clusters formed in the same stellar nursery. orange stars adorn the area, all vari- ables. One of these vermillion jewels (BU Per) hovers north of NGC 869, and another (AD Per) rests in the south- ern reaches of the pair, about halfway between the clusters. FZ Per colors NGC 884’s western outskirts, while V0439 and V0403 Per shine in the east- northeast. The smoldering ember RS Per burns east-southeast of the sparse core. The Double Cluster nearly bridges the ﬁeld through my 10-inch scope at 68×, yet the view is astounding, with each cluster ﬂaunting more than 100 stars. NGC 869’s smile and nose gain a pair of batlike ears to the north-north- west, the smiling bat covering about 3′. Recent studies indicate the clusters are not merely a line-of-sight coinci- dence. According to a 2010 paper by Thayne Currie and colleagues in the Astrophysical Journal u The light from the open cluster M34 takes about 1,500 years to reach Earth. M34 lies about halfway between the stars Alpha (α) and Beta (β) Persei. Supplement Series, these youthful clus- ters are approximately 14 million years old. Four different estimates loosely place NGC 869 in a realm 7,650 light- years away from us, but with NGC 884 systematically in the foreground by about 176 light-years. Also in Perseus, Messier 34 is an odd-looking open cluster through the 130-mm scope at 37×. The outer boundary looks boxy, but with a rounded southwestern corner. Bright stars near the middle of the northern and southern borders shine orange and deep yellow, respectively. There’s a bizarre pattern of stars in the core, like a bug-eyed guy running in terror with his arms ﬂung wide. His eyes blaze a bit northwest of the cluster’s center, and his bent legs stretch southeastward. About 75 stars lodge within ½° of sky. M34 was most likely discovered by Giovanni Battista Hodierna, as men- tioned in the text of his 1654 De Admiran- dis Coeli Characteribus (On the Admirable AG he celestial meridian is an imagi- nary line in the sky that runs due north to due south and passes through a point straight overhead. For those of us in the Northern Hemisphere, the wonders of the night sky are best wit- nessed when they traverse the merid- ian between Polaris and the southern horizon. That’s when they’re highest in our sky and least diminished by Earth’s atmosphere. This month’s deep-sky tour will showcase marvels berthed near the meridian on the all-sky chart at the center of this magazine. Our ﬁrst stop is the outstanding Double Cluster in Perseus, NGC 869 and NGC 884. The pair is easily seen as a gauzy smudge to the unaided eye from my semirural home. It was likely familiar to the ancients, but the earliest known record comes from the Greek astronomer Hipparchus of Nicaea, who lived during the second century BC. The Double Cluster is breathtaking through my 130-mm refractor at 48×. NGC 869’s central concentration holds about 25 stars, including a U-shaped group of ﬁve stars that looks like a big smile with a bright nose star west- northwest. At least 60 additional suns plump out the cluster. NGC 884 is less concentrated with only 10 or so stars clumped in the core and about 70 stars strewn around them. Together the clus- ters span nearly 1°, their edges blending gradually into the background sky. Most of the cluster stars gleam white to blue-white, but some strikingly red-

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