Sky and Telescope - February 2016 - 51

Sue French

Sue French welcomes your comments at scfrench@nycap.rr.com.

white, 3.6-magnitude primary. The noted 19th-century
double-star observers William H. Smyth and Thomas
William Webb described the secondary as pale green
and garnet, respectively. In her book Double Stars for
Small Telescopes, Sissy Haas enthusiastically describes
this showcase pair: "Fantastic colors - this is a bright

HD 41312

POSS-II / CALTECH / STSCI / PALOMAR OBSERVATORY

ESO 489-1

ESO 489-1, a possible open cluster remnant, twinkles southeast
of HD 41312. Use the yellow-orange K3III star, HD 41312, as a
waymark.
CARNEGIE-IRVINE GALAXY SURVEY (LUIS C. HO / AARON J. BARTH / SONG HUANG / ZHAO-YU LI / CHIEN Y. PENG)

Always fond of ﬂat galaxies, I sought out nearby NGC
1886, a miniature version of the Needle Galaxy (NGC
4565 in Coma Berenices). Look for it 54′ northwest of
M79 and east of an 11′-long line of stars, magnitudes 9.3
to 10.0. If you follow the line from southeast to northwest,
you'll see the galaxy sitting beside the second star in the
line. Through my 10-inch scope at 166×, NGC 1886 is
a wispy streak of light tipped east-northeast. It appears
quite faint and is best seen with averted vision, so I had
no hope of spotting the dark lane that runs its length. I
suspect that would take a very large telescope. Is a view of
the dark lane beyond reach with even the largest scopes
of amateur skygazers? Tell me if you snare it.
Tucked in the southeastern corner of Lepus, ESO
489-1 is a lovely collection of stars that may be an open
cluster remnant, the relic of a cluster whose stars have
mostly dispersed. Such groups are depleted in low-mass
stars but possess a comparatively high fraction of stable
multiple systems. ESO 489-1 is thought to be about 3,200
light-years distant and roughly 700 million years old.
ESO 489-1 is parked 36′ southeast of the yelloworange, 5.0-magnitude star HD 41312 (SAO 171180). In
my 10-inch reﬂector at 44×, it's an easily noticed group
of stars, 10th magnitude and fainter. The four brightest form a 3.3′ × 2′ parallelogram at the cluster's center.
Viewed at 90×, about 20 stars join the parallelogram,
many in raggedy chains spanning 10′.
An imaginary line drawn from Beta to Gamma (γ)
Leporis and then extended the same distance will take us
to our next target, the spiral galaxy NGC 2139. My 10-inch
scope at 44× merely shows a small, round smudge, a bit
brighter toward the center, bracketed by a 10th-magnitude
star south and a star pair north-northwest, magnitudes 11
and 12½. At 118× the galaxy appears mottled and slightly
oval. It spans about 1½′ and embraces a brighter core and
stellar nucleus. There's a dim star near NGC 2139's northern edge, and two extremely faint stars are intermittently
visible at its western ﬂank.
NGC 2139 looks positively ﬂuﬀ y in deep images. It's
a late-type spiral, which means that it has ﬂeecy arms
and a small core. NGC 2139 bears distorted features that
could be evidence of a merger with another galaxy some
tens of millions of years ago. The event may have also
sparked formation of the large star cluster, perhaps 800
thousand solar masses, that's slightly oﬀset from the
galaxy's center. This remarkable galaxy is roughly 95
million light-years distant.
Gamma (γγ ) Leporis, one of the pointer stars we used
to locate NGC 2139, is a colorful double star that's easily
split at low power. Its components are widely separated
even at 17× through my 105-mm refractor. The orange,
6.3-magnitude companion hovers north of its yellow-

NGC 2139

The "ﬂuﬀ y" structure of NGC 2139 will show as a circular
smudge of light, slightly brighter at the core, in your eyepiece.

Sk yandTelescope.com Februar y 2016

http://www.SkyandTelescope.com

Sky and Telescope - February 2016

Table of Contents for the Digital Edition of Sky and Telescope - February 2016