Theta Ophiuchi — Double Star in Ophiuchus
Observe
1Physical Properties
Magnitude
3.27
Range
3.26 - 3.29
Period
3.4 hours
Variable Type
Beta Cephei (Pulsating)
Spectral Type
B2 IV
subgiant
Star Color
Blue
(B-V -0.22)
Distance
436 ly
2Position & Identifiers
RA
17h 22m 00.6s
Dec
-24° 59' 58.0"
Constellation
Ophiuchus
(Oph)
HR
6453
HIP
84970
HD
157056
SAO
185320
Bayer
Theta
Flamsteed
42 Oph
Variable ID
The Oph
Querying VizieR catalog...
3How easy to spot?
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| Equipment | Bortle 3 | Bortle 4 | Bortle 5 |
|---|---|---|---|
| Naked eye Naked eye | Easy | Easy | Medium+ |
| 50 mm finder 50mm finder | Easy | Easy | Easy |
| 150 mm telescope 150mm scope | Easy | Easy | Easy |
Easy
Medium
Hard
Very hard
Impossible
Bortle 3 = rural · 4 = outer suburbs · 5 = suburbs
4Visibility
Set a location in User Settings to see visibility data.
Best season
May – Jul
(peak: Jun)
5Light Curve
6Multiple Star System
Separation
0.1″
Companion Mag
6.2
Position Angle
55°
Star Colors
A: Blue
B: White
Discoverer
CHR 182
Separation over time
Period: 28.2 y
Eccentricity: 0.400
Now: 0.10", PA 233°
+ 0.17" in 5 years
Apparent separation over time, computed from ORB6 orbital elements. Steep curves indicate fast-changing pairs — catch them while they're splittable.
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8
Size Comparison
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9
Compare Stars
10
Spectral Classification
11
Hertzsprung-Russell Diagram
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12
Stellar Lifecycle
13
Blackbody Spectrum
14
Stellar Absorption Spectrum
Simulated absorption spectrum based on spectral type. Hover over lines to identify elements.
15
Stellar Fusion
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16Stellar Notes
Beta C 3.25 - 3.31V, multi-periodic 0.140531 and others ranging from 0.0464 to 0.1399d.
3.6, 5.6v, sep. 0.00003", 11.44d. K 5.25k/s, V0 -1.5k/s. Also 0.29d.
Sco OB2; Sco-Cen cluster; Sco-Cen assoc.; upper Sco.
17
Light Travel Time Machine
18
Relativistic Travel
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.
39 Oph
Colorful double, sep 10.7″
Double Star
mag 5.20
1.2°
Ophiuchus
NGC 6355
Compact globular cluster
Globular Cluster
mag 9.6
1.4°
Ophiuchus
Guniibuu
HIP 84405; 36 Ophiuchi
Easy double, sep 5.2″
Double Star
mag 5.07
2.2°
Ophiuchus
Xi Oph
Colorful double, sep 4.1″
Double Star
mag 4.39
3.9°
Ophiuchus
3 Sgr
Pulsating variable, period 7.0d
Variable Star
mag 4.54
6.4°
Sagittarius
NGC 6469
Open cluster
Open Cluster
mag 8.0
7.6°
Sagittarius
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