Hydra

Hydra (abbreviation: Hya), the Water Serpent, is the largest constellation of all (following the dismantling of Argo Navis), stretching across a huge swathe of the southern sky. See below for details of the constellation's brightest stars and interesting deep sky objects.

Stars brighter than magnitude 4.0
star	vis mag	abs mag	spec type	distance (ly)	RA (h m s)	Dec (° ' ")
Alpha (Alphard)	1.99	-1.69	K3III	177	09 27 35	-08 39 31
Gamma	2.99	-0.55	G8IIIa	132	13 18 55	-23 10 17
Zeta	3.11	-0.22	G8III	151	08 55 24	+05 56 44
Nu	3.11	-0.03	K0III	139	10 49 37	-16 11 37
Pi	3.25	0.75	K2III-IIIbCN	101	14 06 22	-26 40 56
Epsilon	3.38	0.29	G0III	135	08 46 47	+06 25 07
Xi	3.54	0.55	G8III	129	11 33 00	-31 51 27
Lambda	3.61	0.88	K0IIICN	115	10 10 35	-12 21 15
Mu	3.83	-0.58	K4.5III	248	10 26 05	-16 50 11
Theta	3.89	0.90	B9.5V	129	09 14 22	+02 18 51

Other objects of interest
name	type of object	notes
Ghost of Jupiter	planetary nebula	NGC 3242. See separate entry
M48 (NGC 2548)	open cluster	On the boundary of Hydra and Monoceros and at the edge of naked-eye visibility. Magnitude 5.8; diameter 54'; RA 08h 13.8m, Dec –05° 48'
M68 (NGC 4590)	globular cluster	Discovered by Pierre Méchain in 1780. Magnitude 8.2; diameter 12'; distance 39,000 light-years; RA 12h 39.5m, Dec –26° 45'
M83 (NGC 5236)	galaxy	A face-on type Sc spiral just outside the Local Group. Magnitude 8.2; distance 8.5 million light-years; RA 13h 37.0m, Dec –29° 52'