Sky and Telescope - September 2018 - 57

14

Star magnitudes

16
3
4
5
6
7
8

13

12

+40°
8
10

Σ 2894

Teutsch 39

+38°

1

Σ 2876
7426

LACERTA

h975

22h 50m

22h 40m

22h 30m

+36°

22h 20m

+34°
+56°

Be 94

7226

+54°

7245
IC 1442

LACERTA
IC 1434
Star magnitudes

blooms within the cluster through my
15-inch reﬂector at 345×. In the cluster's southern reaches, 16 stars neatly
outline two wide, basal leaves. The
bright star in the north is the ﬂower's
blossom, and a solitary star between it
and the leaves indicates a curved stem,
with the ﬂower drooping above the
western leaf. Although most of the stars
dimly shine at about 14th magnitude, I
thought it a great treat to pick out this
shy little wallﬂower.
Back in Lacerta, let's travel 2.9° east
of Beta to the open cluster Berkeley
98. At 63× the 130-mm scope serves up
seven faint stars in a skinny, 4½′-long
wedge that points northeast. A power of
164× places 13 stars in the wedge and
two more within the nominal 6′ span
of the cluster, while 234× draws out a
total of 18 stars. A better view comes
with the 10-inch scope at 187×, which
awards the group at least 25 stars.
When you gaze at Berkeley 98, you're
seeing an exceptionally elderly cluster,
about 2.5 billion years old. The stars in
most open clusters disperse within a
few hundred million years.
Our ﬁnal visit will be paid to NGC
7394, situated 1.2° east-southeast of
Berkeley 98. Two 7th-magnitude stars
13′ apart and tangent to the cluster's
eastern side help pinpoint the group.
The northern jewel gleams yellowwhite, while the southern one shines
yellow. My 130-mm refractor 23×
tenders a gathering of 11 faint stars
stretching northwest from the southern
star of the pair. At 63×, I see about 20
stars in a band that's 10′ long and 4′ to
5′ wide. The group's brightest gem glows
a warm yellow-orange. The 10-inch
scope at 68× boosts the star count to
25, and at 166× the yellow-orange star
gains a very faint companion 11′ to the
west. This is another of John Herschel's
doubles, h1820.
While NGC 7394 looks like a reasonably obvious collection of stars, its
existence as a physical group is somewhat dubious, and indeed it doesn't
appear in most cluster catalogs. The
majority of the star clusters listed in the
New General Catalogue of Nebulae and
Clusters of Stars (NGC) were discovered

3
4
5
6
7
8

7394

Be 98
7296

+52°

`

9

+50°

_
7243

4

+48°
5

23h 00m

22h 40m

by their appearance through a telescope
or on a photographic plate, at a time
when determining their true nature
was generally not possible. Some remain
questionable to this day. The next time
you eyeball NGC 7394, ask yourself

22h 20m

22h 00m

whether or not you'd log it as a possible
open star cluster.
¢ Contributing Editor SUE FRENCH likes
all manner of critters, including lizards
with or without stars.
sk yandtelescope.com * S E P TE M B E R 2 018

57
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Sky and Telescope - September 2018

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