Basic object information
Object name: NGC 4639
Object type: Galaxy
Magnitude: 11.4
Size: 2.9'x2.0'
Position angle: 123
Object classification: SBbc Ring
Description: pB,S,E,R,*12 sf 1'
Notes: H II 125;comp 2.9';NGC 4654 @ 17.5'

Catalog information
RA (J2000.0): 12h 42m 54.0s
Dec (J2000.0): +13 15' 00"
Constellation: Virgo

Observer: Iiro Sairanen
Obs. place: Ania, Pirkkala, Finland
Date/Time: 18/19.4.2009 2:50

Telescope: Newton 300/1500 mm

Magn: 300x
Field: 14'
Background sky: 2 (21.05)Visuality: II

Filter:
NE Lim.mag: 6.9
Seeing: 3
Height: 36

Weather: -6C, gusts of wind

Weak arcs of ring-structure were visible on the NW and SE side of the elliptical core. NW arc is larger and easier.