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NGC 6388 — Globular Cluster in Scorpius

Globular Cluster Excellent (70/100)
Magnitude 6.9m GlobularCluster Scorpius (Sco) Visible
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1Properties

Magnitude 6.9
Angular Size 8.4′
glob. cl. , vB, L, R, pg, psvmbM, rrr, st 17...

Position & Identifiers

RA 17h 36m 18.0s
Dec -44° 43' 60.0"
Constellation Scorpius (Sco)
Catalog NGC 6388
Physical size
9.8 light-years across — tens of light-years across — wider than the solar neighbourhood

2How easy to spot?

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Telescope Bortle 3 Bortle 4 Bortle 5
80mm refr. Easy Easy Easy
150mm Newt. Easy Easy Easy
C8 203mm Easy Easy Easy
Easy Medium Hard Very hard Impossible

Bortle 3 = rural · 4 = outer suburbs · 5 = suburbs

Easy on Seestar S50

3Visibility

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Best season May – Jul (peak: Jun)

4 Eyepiece View

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125x TFOV: 0.4° Lim. mag: 13.6
N E

NGC 6388 · 8.4′ diameter · N up, E left

5 Best Magnification

6Metallicity

-2.5 -2.0 -1.5 -1.0 -0.5 0.0 Ancient halo Disc / bulge M92 M3 M71 NGC 6388 [Fe/H] = -0.55

[Fe/H] = -0.55 — these stars formed from gas about 3.5× poorer in iron than the Sun.

7Concentration class

I II III IV V VI VII VIII IX X XI XII Dense (I) Loose (XII) III Core / half-light / tidal tidal 6.8′ half 0.5′ core 0.12′

Shapley-Sawyer class III — extremely centrally concentrated core.

Explore

8 Classification Decoder

Nearby in the Sky

Other targets within a few degrees — pan your scope a little and keep exploring.

Visibility scores assume a 150 mm Newton at Bortle 4.

Sargas
HIP 86228; Theta Scorpii
Easy
Easy double, sep 6.5″
Double Star mag 1.87 1.7° Scorpius
NGC 6322
Easy
Rich open cluster
Open Cluster mag 6.0 3.7° Scorpius
NGC 6496
Easy
Globular cluster — dense ball of ancient stars
Globular Cluster mag 9.2 4.1° Scorpius
NGC 6352
Easy
Globular cluster — dense ball of ancient stars
Globular Cluster mag 8.2 4.1° Ara
NGC 6541
Easy
Globular cluster — dense ball of ancient stars
Globular Cluster mag 6.6 5.8° Corona Australis
NGC 6441
Easy
Globular cluster — dense ball of ancient stars
Globular Cluster mag 7.4 8.1° Scorpius
V861 Sco
Medium
Eclipsing binary, period 7.8d
Variable Star mag 6.15 8.3° Scorpius
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