Sky & Telescope - July 2022 - 55
I began by aiming the refractor at
+22°
orangey Delta Sagittae, one of only two
stars in the constellation I could spot
with my bare eyes. From there it was
a short hop to fainter Zeta less than
¾° northeast. Zeta looks single at low
power, but it's a strongly unbalanced
binary known as Struve (Σ) 2585. Its
primary element is magnitude 5.0,
while the secondary sun, 8.3″ away, is
four magnitudes dimmer. My apochromat
split the pair at 50×, and it was
quite appealing at 100×.
From Zeta Sagittae, I re-aimed the
apo 1° northeastward to a spot just
across the Sagitta-Vulpecula border.
There, at the foot of the Fox, my 8×50
finderscope picked up a 40′-long isosceles
triangle, the baseline of which is
anchored by two 7th-magnitude stars.
The triangle's vertex to the east-northeast
is marked by the superb low-power
double Struve Appendix Catalogue
I 48 (ΣI48). Its 7.1- and 7.3-magnitude
components, 41.7″ apart, make this an
eye-catching " headlights " double. And
those headlights gleamed nicely in my
apo at 28×.
Also on my list was 6.6-magnitude
Theta (θ) Sagittae, which glimmers
1.5° northeast of Eta (the tip of my
arrow). Theta is a triple, also designated
Σ2637AB and Σ2637AC. The 8.9-magnitude
secondary (component B) lies 11.6″
from Theta, while the 7.5-magnitude
tertiary (C) is separated by a breezy
91.9″. The triangular system was glorious
in the apo at 28×.
Main Messier Meal
After the appetizers, I was hungry for
the main course: globular cluster M71.
To be honest, though, M71 isn't a
hearty meal. Viewed in a backyard telescope,
this lower-tier globular is small,
faint, and not very globular-like.
Deep-sky observers - me included -
often comment that the visual appearance
of M71 is somewhere between an
unconcentrated globular and a remote
open cluster. The little guy is only 7.2′
in diameter and glows lamely at magnitude
8.4. Its most prominent members
are magnitude 12.1, and the vast
majority are much dimmer. The lack of
VULPECULA
θ (Σ2637)
ΣI48
η
γ
ζ (Σ2585)
SAGITTA
3
4
5
6
7
8
9
M71
Harvard 20
δ
α
+18°
13
11
10
ε
+16°
20h 10m
20h 00m
19h 50m
19h 40m
LITTLE ARROW Sagitta is tiny and dim but not hard to find in the band of the Milky Way between
much larger neighbors Cygnus and Aquila. Oddly, neither Alpha (α) nor Beta (β) Sagittae is
the constellation's brightest star - that honor goes to 3.5-magnitude Gamma (γ).
luster is a bit odd, given M71's distance
of approximately 13,000 light-years -
not far for a globular (brilliant M13 in
Hercules is almost twice as distant).
Fortunately, M71 enjoys a rich
setting in the glorious summer Milky
Way. Situated halfway between Delta
and Gamma Sagittae, M71 lies 21′
east-northeast of 9 Sagittae, a 6th-magnitude
marker 1.2° east of Delta. The
scene is attractive - a couple of 9thmagnitude
stars shine ¼° east-southeast
of the globular, while a half-dozen
mostly brighter ones (9 Sagittae among
them) are clumped a similar distance
westward. A 10th-magnitude guardian
stands protectively near the northeast
edge of the fragile cluster. Fainter sparks
are everywhere.
That lovely field, spanning about
40′, showed beautifully in the refractor
at 38×. M71 itself was a pale puff
that resembled an uncondensed, tailless
comet adrift in space. Upping the
magnification to 100× turned the comet
into a cluster. M71 exhibited a distinct
graininess bordering on partial resolution,
though with no concentration
toward the center. Increasing to 129×
didn't help, as the cluster's light was
spread too thinly to observe effectively.
My 8-inch Dobsonian working at
50× framed the field perfectly. M71
exhibited individual stars at 75× and
was pleasingly (albeit faintly) resolved
at 175×. The outskirts of the cluster
blended seamlessly into the surroundings.
To my eye, it seemed as though a
portion of the Milky Way had gathered
into a ragged pile of grain. I estimated
its diameter to be maybe 4′. Several
leading lights - possibly foreground
stars - were scattered atop the diminutive
patch. One cluster-width northeastward,
I detected a few more individual
specks of light dotting the area between
the hazy patch and the guardian star. In
the end, the best view was had at 100×.
Some folks might dismiss M71 as a
poor-quality globular. I disagree - I've
seen way worse. My nomination for the
worst glob blob (Messier division) is
M72, in Aquarius. M72 is often a noshow
in my pea-soup of a sky, whereas
the lone Sagitta Messier manages to
punch through the suburban murk.
Give it a try!
Care for a little dessert? An obscure
sk yand tele scope .o r g * JULY 2022 55
β
+20°
9
Star magnitudes
http://www.skyandtelescope.com
Sky & Telescope - July 2022
Table of Contents for the Digital Edition of Sky & Telescope - July 2022
Contents
Sky & Telescope - July 2022 - Cover1
Sky & Telescope - July 2022 - Cover2
Sky & Telescope - July 2022 - 1
Sky & Telescope - July 2022 - Contents
Sky & Telescope - July 2022 - 3
Sky & Telescope - July 2022 - 4
Sky & Telescope - July 2022 - 5
Sky & Telescope - July 2022 - 6
Sky & Telescope - July 2022 - 7
Sky & Telescope - July 2022 - 8
Sky & Telescope - July 2022 - 9
Sky & Telescope - July 2022 - 10
Sky & Telescope - July 2022 - 11
Sky & Telescope - July 2022 - 12
Sky & Telescope - July 2022 - 13
Sky & Telescope - July 2022 - 14
Sky & Telescope - July 2022 - 15
Sky & Telescope - July 2022 - 16
Sky & Telescope - July 2022 - 17
Sky & Telescope - July 2022 - 18
Sky & Telescope - July 2022 - 19
Sky & Telescope - July 2022 - 20
Sky & Telescope - July 2022 - 21
Sky & Telescope - July 2022 - 22
Sky & Telescope - July 2022 - 23
Sky & Telescope - July 2022 - 24
Sky & Telescope - July 2022 - 25
Sky & Telescope - July 2022 - 26
Sky & Telescope - July 2022 - 27
Sky & Telescope - July 2022 - 28
Sky & Telescope - July 2022 - 29
Sky & Telescope - July 2022 - 30
Sky & Telescope - July 2022 - 31
Sky & Telescope - July 2022 - 32
Sky & Telescope - July 2022 - 33
Sky & Telescope - July 2022 - 34
Sky & Telescope - July 2022 - 35
Sky & Telescope - July 2022 - 36
Sky & Telescope - July 2022 - 37
Sky & Telescope - July 2022 - 38
Sky & Telescope - July 2022 - 39
Sky & Telescope - July 2022 - 40
Sky & Telescope - July 2022 - 41
Sky & Telescope - July 2022 - 42
Sky & Telescope - July 2022 - 43
Sky & Telescope - July 2022 - 44
Sky & Telescope - July 2022 - 45
Sky & Telescope - July 2022 - 46
Sky & Telescope - July 2022 - 47
Sky & Telescope - July 2022 - 48
Sky & Telescope - July 2022 - 49
Sky & Telescope - July 2022 - 50
Sky & Telescope - July 2022 - 51
Sky & Telescope - July 2022 - 52
Sky & Telescope - July 2022 - 53
Sky & Telescope - July 2022 - 54
Sky & Telescope - July 2022 - 55
Sky & Telescope - July 2022 - 56
Sky & Telescope - July 2022 - 57
Sky & Telescope - July 2022 - 58
Sky & Telescope - July 2022 - 59
Sky & Telescope - July 2022 - 60
Sky & Telescope - July 2022 - 61
Sky & Telescope - July 2022 - 62
Sky & Telescope - July 2022 - 63
Sky & Telescope - July 2022 - 64
Sky & Telescope - July 2022 - 65
Sky & Telescope - July 2022 - 66
Sky & Telescope - July 2022 - 67
Sky & Telescope - July 2022 - 68
Sky & Telescope - July 2022 - 69
Sky & Telescope - July 2022 - 70
Sky & Telescope - July 2022 - 71
Sky & Telescope - July 2022 - 72
Sky & Telescope - July 2022 - 73
Sky & Telescope - July 2022 - 74
Sky & Telescope - July 2022 - 75
Sky & Telescope - July 2022 - 76
Sky & Telescope - July 2022 - 77
Sky & Telescope - July 2022 - 78
Sky & Telescope - July 2022 - 79
Sky & Telescope - July 2022 - 80
Sky & Telescope - July 2022 - 81
Sky & Telescope - July 2022 - 82
Sky & Telescope - July 2022 - 83
Sky & Telescope - July 2022 - 84
Sky & Telescope - July 2022 - Cover3
Sky & Telescope - July 2022 - Cover4
https://www.nxtbook.com/nxtbooks/aas/st_202411
https://www.nxtbook.com/nxtbooks/aas/st_202410
https://www.nxtbook.com/nxtbooks/aas/st_202409
https://www.nxtbook.com/nxtbooks/aas/st_202408
https://www.nxtbook.com/nxtbooks/aas/st_202407
https://www.nxtbook.com/nxtbooks/aas/st_202406
https://www.nxtbook.com/nxtbooks/aas/st_202405
https://www.nxtbook.com/nxtbooks/aas/st_202404_qr
https://www.nxtbook.com/nxtbooks/aas/st_202404
https://www.nxtbook.com/nxtbooks/aas/st_202403
https://www.nxtbook.com/nxtbooks/aas/st_202402
https://www.nxtbook.com/nxtbooks/aas/st_202401_aus
https://www.nxtbook.com/nxtbooks/aas/st_202401
https://www.nxtbook.com/nxtbooks/aas/st_202312_aus
https://www.nxtbook.com/nxtbooks/aas/st_202312
https://www.nxtbook.com/nxtbooks/aas/st_202311
https://www.nxtbook.com/nxtbooks/aas/st_202310
https://www.nxtbook.com/nxtbooks/aas/st_202309
https://www.nxtbook.com/nxtbooks/aas/st_202308
https://www.nxtbook.com/nxtbooks/aas/st_202307
https://www.nxtbook.com/nxtbooks/aas/st_202306
https://www.nxtbook.com/nxtbooks/aas/st_202305
https://www.nxtbook.com/nxtbooks/aas/st_202304
https://www.nxtbook.com/nxtbooks/aas/st_202304_qr
https://www.nxtbook.com/nxtbooks/aas/st_202303
https://www.nxtbook.com/nxtbooks/aas/st_202302
https://www.nxtbook.com/nxtbooks/aas/st_202301
https://www.nxtbook.com/nxtbooks/aas/st_202212
https://www.nxtbook.com/nxtbooks/aas/st_202211
https://www.nxtbook.com/nxtbooks/aas/st_202210
https://www.nxtbook.com/nxtbooks/aas/st_202209
https://www.nxtbook.com/nxtbooks/aas/st_202208
https://www.nxtbook.com/nxtbooks/aas/st_202207
https://www.nxtbook.com/nxtbooks/aas/st_202206
https://www.nxtbook.com/nxtbooks/aas/st_202205
https://www.nxtbook.com/nxtbooks/aas/st_202204
https://www.nxtbook.com/nxtbooks/aas/st_202203
https://www.nxtbook.com/nxtbooks/aas/st_202202
https://www.nxtbook.com/nxtbooks/aas/st_202201
https://www.nxtbook.com/nxtbooks/aas/st_202112
https://www.nxtbook.com/nxtbooks/aas/st_202111
https://www.nxtbook.com/nxtbooks/aas/st_202110
https://www.nxtbook.com/nxtbooks/aas/st_202109
https://www.nxtbook.com/nxtbooks/aas/st_202108
https://www.nxtbook.com/nxtbooks/aas/st_202107
https://www.nxtbook.com/nxtbooks/aas/st_202106
https://www.nxtbook.com/nxtbooks/aas/st_202105
https://www.nxtbook.com/nxtbooks/aas/st_202104
https://www.nxtbook.com/nxtbooks/aas/st_202103
https://www.nxtbook.com/nxtbooks/aas/st_202102
https://www.nxtbook.com/nxtbooks/aas/st_202101
https://www.nxtbook.com/nxtbooks/aas/skywatch_2021
https://www.nxtbook.com/nxtbooks/aas/st_202012
https://www.nxtbook.com/nxtbooks/aas/st_202011
https://www.nxtbook.com/nxtbooks/aas/st_202010
https://www.nxtbook.com/nxtbooks/aas/st_202009
https://www.nxtbook.com/nxtbooks/aas/st_202008
https://www.nxtbook.com/nxtbooks/aas/st_202007
https://www.nxtbook.com/nxtbooks/aas/st_202006
https://www.nxtbook.com/nxtbooks/aas/st_202005
https://www.nxtbook.com/nxtbooks/aas/st_202004
https://www.nxtbook.com/nxtbooks/aas/st_202003
https://www.nxtbook.com/nxtbooks/aas/st_202002
https://www.nxtbook.com/nxtbooks/aas/st_202001
https://www.nxtbook.com/nxtbooks/aas/st_201912
https://www.nxtbook.com/nxtbooks/aas/st_201911
https://www.nxtbook.com/nxtbooks/aas/st_201910
https://www.nxtbook.com/nxtbooks/aas/st_201909
https://www.nxtbook.com/nxtbooks/aas/st_201908
https://www.nxtbook.com/nxtbooks/aas/st_201907
https://www.nxtbook.com/nxtbooks/aas/st_201906
https://www.nxtbook.com/nxtbooks/aas/st_201905
https://www.nxtbook.com/nxtbooks/aas/st_201904
https://www.nxtbook.com/nxtbooks/aas/st_201903
https://www.nxtbook.com/nxtbooks/aas/st_201902
https://www.nxtbook.com/nxtbooks/aas/st_201901
https://www.nxtbook.com/nxtbooks/aas/st_201812
https://www.nxtbook.com/nxtbooks/aas/st_201811
https://www.nxtbook.com/nxtbooks/aas/st_201810
https://www.nxtbook.com/nxtbooks/aas/st_201809
https://www.nxtbook.com/nxtbooks/aas/st_201808
https://www.nxtbook.com/nxtbooks/aas/st_201807
https://www.nxtbook.com/nxtbooks/aas/st_201806
https://www.nxtbook.com/nxtbooks/aas/st_201805
https://www.nxtbook.com/nxtbooks/aas/st_201804
https://www.nxtbook.com/nxtbooks/aas/st_201803
https://www.nxtbook.com/nxtbooks/aas/st_201802
https://www.nxtbook.com/nxtbooks/aas/st_201801
https://www.nxtbook.com/nxtbooks/aas/st_201712
https://www.nxtbook.com/nxtbooks/aas/st_201711
https://www.nxtbook.com/nxtbooks/aas/st_201710
https://www.nxtbook.com/nxtbooks/aas/st_201709
https://www.nxtbook.com/nxtbooks/aas/st_201708
https://www.nxtbook.com/nxtbooks/aas/st_201707
https://www.nxtbook.com/nxtbooks/aas/st_201706
https://www.nxtbook.com/nxtbooks/aas/st_201705
https://www.nxtbook.com/nxtbooks/aas/st_201704
https://www.nxtbook.com/nxtbooks/aas/st_201703
https://www.nxtbook.com/nxtbooks/aas/st_201702
https://www.nxtbook.com/nxtbooks/aas/st_201701
https://www.nxtbook.com/nxtbooks/aas/st_201612
https://www.nxtbook.com/nxtbooks/aas/st_201611
https://www.nxtbook.com/nxtbooks/aas/st_201610
https://www.nxtbook.com/nxtbooks/aas/st_201609
https://www.nxtbook.com/nxtbooks/aas/st_201608
https://www.nxtbook.com/nxtbooks/aas/st_201607
https://www.nxtbook.com/nxtbooks/aas/st_201606
https://www.nxtbook.com/nxtbooks/aas/st_201605
https://www.nxtbook.com/nxtbooks/aas/st_201604
https://www.nxtbook.com/nxtbooks/aas/st_201603
https://www.nxtbook.com/nxtbooks/aas/st_201602
https://www.nxtbook.com/nxtbooks/aas/st_201601
https://www.nxtbook.com/nxtbooks/aas/st_201512
https://www.nxtbook.com/nxtbooks/aas/st_201511
https://www.nxtbook.com/nxtbooks/aas/st_201510
https://www.nxtbook.com/nxtbooks/aas/st_201509
https://www.nxtbook.com/nxtbooks/aas/st_201508
https://www.nxtbook.com/nxtbooks/aas/st_201507
https://www.nxtbook.com/nxtbooks/aas/st_201506
https://www.nxtbook.com/nxtbooks/aas/st_201505
https://www.nxtbook.com/nxtbooks/aas/st_201504
https://www.nxtbook.com/nxtbooks/aas/st_201503
https://www.nxtbook.com/nxtbooks/aas/st_201502
https://www.nxtbook.com/nxtbooks/aas/st_201501
https://www.nxtbook.com/nxtbooks/aas/st_201412
https://www.nxtbook.com/nxtbooks/aas/st_201411
https://www.nxtbook.com/nxtbooks/aas/st_201410
https://www.nxtbook.com/nxtbooks/aas/st_201409
https://www.nxtbook.com/nxtbooks/aas/st_201408
https://www.nxtbook.com/nxtbooks/aas/st_201407
https://www.nxtbook.com/nxtbooks/aas/st_201406
https://www.nxtbook.com/nxtbooks/aas/st_mars
https://www.nxtbook.com/nxtbooks/aas/st_201405
https://www.nxtbook.com/nxtbooks/aas/st_201404
https://www.nxtbook.com/nxtbooks/aas/st_201403
https://www.nxtbook.com/nxtbooks/aas/st_201402
https://www.nxtbook.com/nxtbooks/aas/st_201401
https://www.nxtbook.com/nxtbooks/aas/st_201312
https://www.nxtbook.com/nxtbooks/aas/st_201311
https://www.nxtbook.com/nxtbooks/aas/st_201310
https://www.nxtbook.com/nxtbooks/aas/st_201309
https://www.nxtbook.com/nxtbooks/aas/st_201308
https://www.nxtbook.com/nxtbooks/aas/st_201307
https://www.nxtbook.com/nxtbooks/aas/st_201306
https://www.nxtbook.com/nxtbooks/aas/st_201305
https://www.nxtbook.com/nxtbooks/aas/st_201304
https://www.nxtbook.com/nxtbooks/aas/st_201303
https://www.nxtbook.com/nxtbooks/aas/st_201302
https://www.nxtbook.com/nxtbooks/aas/st_201301
https://www.nxtbook.com/nxtbooks/aas/st_201212
https://www.nxtbook.com/nxtbooks/aas/st_201211
https://www.nxtbook.com/nxtbooks/aas/st_201210
https://www.nxtbook.com/nxtbooks/aas/st_201209
https://www.nxtbook.com/nxtbooks/aas/st_201208
https://www.nxtbook.com/nxtbooks/aas/st_201207
https://www.nxtbook.com/nxtbooks/aas/st_201206
https://www.nxtbook.com/nxtbooks/aas/st_201205
https://www.nxtbook.com/nxtbooks/aas/st_201204
https://www.nxtbook.com/nxtbooks/aas/st_201203
https://www.nxtbook.com/nxtbooks/aas/st_201202
https://www.nxtbook.com/nxtbooks/aas/st_201201
https://www.nxtbook.com/nxtbooks/aas/st_201112
https://www.nxtbook.com/nxtbooks/aas/st_201111
https://www.nxtbook.com/nxtbooks/aas/st_201110
https://www.nxtbook.com/nxtbooks/aas/st_201109
https://www.nxtbook.com/nxtbooks/aas/st_201108
https://www.nxtbook.com/nxtbooks/aas/st_201107
https://www.nxtbook.com/nxtbooks/aas/st_201106
https://www.nxtbook.com/nxtbooks/aas/st_201105
https://www.nxtbook.com/nxtbooks/aas/st_201104
https://www.nxtbook.com/nxtbooks/aas/st_201103
https://www.nxtbook.com/nxtbooks/aas/st_201102
https://www.nxtbook.com/nxtbooks/aas/st_201101
https://www.nxtbook.com/nxtbooks/aas/st_201012
https://www.nxtbook.com/nxtbooks/aas/st_201011
https://www.nxtbook.com/nxtbooks/aas/st_201010
https://www.nxtbook.com/nxtbooks/aas/st_201009
https://www.nxtbook.com/nxtbooks/aas/st_201008
https://www.nxtbook.com/nxtbooks/aas/st_201007
https://www.nxtbook.com/nxtbooks/aas/st_201006
https://www.nxtbook.com/nxtbooks/aas/st_201005
https://www.nxtbook.com/nxtbooks/aas/st_201004
https://www.nxtbook.com/nxtbooks/aas/st_201003
https://www.nxtbook.com/nxtbooks/aas/st_201002
https://www.nxtbook.com/nxtbooks/aas/st_201001
https://www.nxtbookmedia.com