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Hydra

Genitive: Hydrae

Equatorial 1303 sq° Hya

Brightest star: Alphard

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Mythology

The Water Snake, representing the Lernaean Hydra with multiple heads slain by Heracles as his second labor. Each time he cut off a head, two grew back.

Observing Highlights

The largest constellation in the sky, stretching over 100 degrees. Contains M48 (open cluster), M68 (globular), M83 (Southern Pinwheel Galaxy), and the Ghost of Jupiter Nebula (NGC 3242).

Main Stars

20
Alphard

HIP 46390; Alpha Hya; 30 Hya

1.98 mag 284.4″ B: 9.7 K3IIIa
Gamma Hya

HIP 64962; Gamma Hya; 46 Hya

3.00 mag G8IIIa
Zeta Hya

HIP 43813; Zeta Hya; 16 Hya

3.11 mag G8.5III
Nu Hya

HIP 52943; Nu Hya

3.11 mag K1.5III Hdel-0.5
Pi Hya

HIP 68895; Pi Hya; 49 Hya

3.27 mag K1III-IV
Ashlesha

HIP 43109; Epsilon Hya; 11 Hya

3.38 mag 0.2″ B: 5.6 G7III + A8III-IV:
Xi Hya

HIP 56343; Xi Hya

3.54 mag 74.6″ B: 10.7 G7III
Lambda Hya

HIP 49841; Lambda Hya; 41 Hya

3.61 mag K0III CN+1
Mu Hya

HIP 51069; Mu Hya; 42 Hya

3.81 mag K4III
Theta Hya

HIP 45336; Theta Hya; 22 Hya

3.88 mag 20.6″ B: 9.9 A0V
HIP 41307
3.90 mag A1V
Ukdah

HIP 47431; Iota Hya; 35 Hya

3.91 mag K2 III
Zhang

HIP 48356; Upsilon1 Hya; 39 Hya

4.12 mag G7-III
Delta Hya

HIP 42313; Delta Hya; 4 Hya

4.16 mag 2.7″ B: 10.7 A1Vnn
Beta Hya

HIP 57936; Beta Hya

4.28 mag 0.6″ B: 5.5 B9IIIpSi
Eta Hya

HIP 42799; Eta Hya; 7 Hya

4.30 mag B3V
12 Hya

HIP 43067; 12 Hya

4.32 mag G8-IIIFe-1
Rho Hya

HIP 43234; Rho Hya; 13 Hya

4.36 mag 12.2″ B: 11.9 A0Vn
58 Hya

HIP 72571; 58 Hya

4.41 mag K4III
Minchir

HIP 42402; Sigma Hya; 5 Hya

4.44 mag K1+III

Double Stars

15
HIP 66400
5.78 mag 10.2″ B: 6.6 A7III
HIP 56280
5.64 mag 9.6″ B: 5.7 F8V
17 Hya

HIP 43822; 17 Hya

6.67 mag 4.0″ B: 6.9 A2m
HIP 43798
5.75 mag 64.2″ B: 7.2 K2-3III
20 Hya

HIP 44961; 20 Hya

5.46 mag 7.8″ B: 9.2 G8II
54 Hya

HIP 72197; 54 Hya

4.94 mag 8.1″ B: 7.2 F2III-IV
HIP 56620
5.74 mag 3.4″ B: 7.8 K0III
HIP 52795
6.67 mag 65.9″ B: 7.0 A0III
HIP 42951
6.41 mag 4.7″ B: 7.5 F2IV
HIP 51475
6.51 mag 29.4″ B: 10.2 F7III
R Hya

HIP 65835

4.97 mag 3.5 - 10.9 M M7IIIe
Tau Hya

HIP 46509; Tau1 Hya; 31 Hya

4.60 mag 65.7″ B: 7.3 F6V
HIP 53252
5.24 mag 119.6″ B: 9.6 F6V
HIP 59307
6.17 mag 3.8″ B: 8.0 A0V
Theta Hya

HIP 45336; Theta Hya; 22 Hya

3.88 mag 20.6″ B: 9.9 A0V

Variable Stars

5
R Hya

HIP 65835

4.97 mag 3.5 - 10.9 M M7IIIe
V Hya

HIP 53085

6.00 mag 6.0 - 12.3 SRA C
U Hya

HIP 52009

4.82 mag 4.56 - 5.40 SRB C5II
21 Hya

HIP 45184; 21 Hya

6.11 mag 6.11 - 6.58 EA/DM A3III:m+A0V:
LN Hya

HIP 63159

6.62 mag 6.57 - 6.90 SRD F3Ia

Deep Sky Objects

30
Open Cluster (1)
Messier 48

NGC 2548

5.5 mag 54.
Globular Cluster (1)
Messier 68

NGC 4590

7.8 mag 12.0
Galaxy (27)
Messier 83

NGC 5236

7.6 mag 11.2 SABc
NGC 3621
10.0 mag 10.0 SBcd
NGC 3109
10.0 mag 14.5 SBm
NGC 2835
11.0 mag 6.3 Sc
NGC 2784
10.1 mag 5.1 S0
NGC 3717
12.0 mag 5.8 Sb
NGC 2713
11.7 mag 3.9 SBb
NGC 2992
11.9 mag 4.1 Sa
NGC 2811
11.3 mag 2.7 SBa
NGC 2889
11.8 mag 2.0 SABc
NGC 2935
12.0 mag 3.5 Sb
NGC 3054
12.0 mag 3.9 Sb
NGC 3124
12.0 mag 3.2 Sbc
NGC 3145
12.0 mag 3.3 SBbc
NGC 3312
12.0 mag 3.6 Sb
NGC 3390
12.2 mag 4.0 Sb
NGC 3673
12.0 mag 3.5 Sb
NGC 5078
12.0 mag 3.2 Sa
NGC 5085
12.0 mag 3.4 Sc
NGC 5556
12.0 mag 3.1 Scd
IC 4351
12.0 mag 5.6 Sb
NGC 2989
13.0 mag 1.4 SABb
NGC 2993
12.6 mag 1.6 Sa
NGC 5150
13.0 mag 1.4 SBbc
NGC 5464
13.0 mag 1.0 SBm
NGC 2708
14.0 mag 3.0 SABb
NGC 2815
13.0 mag 3.5 SBb
Planetary Nebula (1)
Ghost of Jupiter

NGC 3242

C59

7.8 mag 0.3