Epsilon Equulei — Double Star in Equuleus
Observe
1Physical Properties
Magnitude
5.23
Spectral Type
F6IV
subgiant
Star Color
Yellow
(B-V 0.46)
Distance
155 ly
2Position & Identifiers
RA
20h 59m 04.4s
Dec
+04° 17' 37.0"
Constellation
Equuleus
(Equ)
HR
8034
HIP
103569
HD
199766
SAO
126428
Bayer
Epsilon
Flamsteed
1 Equ
Double Cat
14499
Querying VizieR catalog...
3How easy to spot?
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| Equipment | Bortle 3 | Bortle 4 | Bortle 5 |
|---|---|---|---|
| Naked eye Naked eye | Medium | Hard+ | Hard |
| 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
Jun – Aug
(peak: Jul)
5Multiple Star System Quadruple
Components
4 (quadruple)
Component IDs
AB
Separation
0.2″
Companion Mag
6.3
Companion Sp
dF4
Position Angle
109°
Star Colors
A: Yellow
B: Yellow-white
Discoverer
STF2737
AB 6.0 F5IV, 6.3 F7IV, 101.485y, a = 0.647". Combined mag., colors. Component C, 7.2v G0V at 11", CPM.
Separation over time
Period: 98.0 y
Eccentricity: 0.712
Now: 0.16", PA 104°
-0.09" 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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6
Size Comparison
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7
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8
Spectral Classification
9
Hertzsprung-Russell Diagram
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10
Stellar Lifecycle
11
Blackbody Spectrum
12
Stellar Absorption Spectrum
Simulated absorption spectrum based on spectral type. Hover over lines to identify elements.
13
Stellar Fusion
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14Stellar Notes
2.0313d, K 15.8k/s, V0 +7.8k/s, asini 0.435.
0.020".
15
Light Travel Time Machine
16
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.
13 Del
Tight double — a rewarding split at 1.5″
Double Star
mag 5.58
3.3°
Delphinus
NGC 6964
Elliptical galaxy
Galaxy
mag 12.7
4.9°
Aquarius
NGC 6934
Globular cluster — dense ball of ancient stars
Globular Cluster
mag 8.9
6.9°
Delphinus
Kappa Del
Easy double, sep 214.6″
Double Star
mag 5.05
7.6°
Delphinus
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