20 Hydrae — Double Star in Hydra
Observe
1Physical Properties
Magnitude
5.46
Spectral Type
G8II
bright giant
Star Color
Orange
(B-V 1.01)
2Position & Identifiers
RA
09h 09m 35.5s
Dec
-08° 47' 16.0"
Constellation
Hydra
(Hya)
HR
3641
HIP
44961
HD
78732
SAO
136622
Flamsteed
20 Hya
Querying VizieR catalog...
3How easy to split?
Primary
5.5 mag
Companion
9.2 mag
Separation
7.8″
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| Telescope | Bortle 3 | Bortle 4 | Bortle 5 |
|---|---|---|---|
| 80 mm refractor 80mm refr. | Medium+ | Medium+ | Medium+ |
| 150 mm Newton 150mm Newt. | Easy | Easy | Easy |
| Celestron C8 (203 mm SCT) C8 203mm | 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
Jan – Mar
(peak: Feb)
5Multiple Star System
Separation
7.8″
Companion Mag
9.2
Position Angle
182°
Star Colors
A: Orange
Discoverer
BRT 426
Eyepiece View
80x
Dawes: 1.9″
TFOV: 0.6°
Realistic = true angular size
A: 5.5 · B: 9.2 · Sep: 7.8″ · PA: 182° · N up, E right
Resolved · Rayleigh: 2.3″ · Dawes: 1.9″ · Eff: 2.3″
Explore
6
Size Comparison
Querying VizieR for stellar data…
7
Compare Stars
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
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.
21 Hya
Eclipsing binary, period 7.7d
Variable Star
mag 6.11
1.8°
Hydra
27 Hya
Colorful double, sep 229.1″
Double Star
mag 4.80
2.8°
Hydra
NGC 2855
Bright spiral galaxy
Galaxy
mag 11.6
4.3°
Hydra
Alphard
HIP 46390; Alpha Hydrae; 30 Hydrae
Bright naked-eye star, mag 2.0
Double Star
mag 1.98
4.4°
Hydra
15 Hya
Tight double — a rewarding split at 1.2″
Double Star
mag 5.54
4.7°
Hydra
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