Delta Hydrae — Double Star in Hydra
Observe
1Physical Properties
Magnitude
4.16
Spectral Type
A1Vnn
Star Color
White
(B-V 0.00)
Distance
99 ly
2Position & Identifiers
RA
08h 37m 39.4s
Dec
+05° 42' 13.0"
Constellation
Hydra
(Hya)
HR
3410
HIP
42313
HD
73262
SAO
116965
Bayer
Delta
Flamsteed
4 Hya
Querying VizieR catalog...
3How easy to split?
Primary
4.2 mag
Companion
10.7 mag
Separation
2.7″
Sign in
and configure your equipment and default location to see a personalized row.
| Telescope | Bortle 3 | Bortle 4 | Bortle 5 |
|---|---|---|---|
| 80 mm refractor 80mm refr. | V. hard | V. hard | V. hard |
| 150 mm Newton 150mm Newt. | V. hard | V. hard | V. hard |
| Celestron C8 (203 mm SCT) C8 203mm | V. hard+ | V. hard+ | V. hard+ |
Easy
Medium
Hard
Very hard
Impossible
Bortle 3 = rural · 4 = outer suburbs · 5 = suburbs
To reach "Medium" at Bortle 3, you'd need at least a 520 mm reflector.
4Visibility
Set a location in User Settings to see visibility data.
Best season
Dec – Feb
(peak: Jan)
5Multiple Star System C: optical
Separation
2.7″
Companion Mag
10.7
Position Angle
263°
Star Colors
A: White
Discoverer
DRS 9
Eyepiece View
80x
Dawes: 1.9″
TFOV: 0.6°
Realistic = true angular size
A: 4.2 · B: 10.7 · Sep: 2.7″ · PA: 263° · N up, E right
Resolved · Rayleigh: 2.3″ · Dawes: 1.9″ · Eff: 2.3″
Explore
7
Size Comparison
Querying VizieR for stellar data…
8
Compare Stars
9
Spectral Classification
10
Hertzsprung-Russell Diagram
Loading HR diagram…
11
Stellar Lifecycle
12
Blackbody Spectrum
13
Stellar Absorption Spectrum
Simulated absorption spectrum based on spectral type. Hover over lines to identify elements.
14
Stellar Fusion
Discover
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.
Explore Nightbase
Related knowledge, tools, and stories — no observation planning required.
Hydra
Mythology, bright stars, and deep-sky highlights.
Constellation
Double Stars — A Guide for Observers
Two suns where one appeared — how to find, split, and appreciate the night sky's finest pairs. From Albireo's gold-and-blue to the Sirius B challenge.
Article
Venus
Phases, transits, and the brightest planet in the sky.
Deep dive
