The sky around RCW 4, 3° across, north up low-power eyepiece, 1° NE 1°
The sky around RCW 4 at true scale, north up and east left, with stars to magnitude 8. The circles show the field of a low-power eyepiece and of 10×50 binoculars.

RCW 4

Emission nebula (H II region) in Monoceros

Emission nebula (H II region) in Monoceros.

MONOCEROS

The box shows where RCW 4 sits in Monoceros.

Constellation
MonocerosMon
Magnitude
-visual
Size
1°apparent
Distance
-light-years
Best month
Februaryat 9 pm
Best with
Telescope

RCW 4 is an emission nebula (H II region) in Monoceros

RCW 4 is an emission nebula (H II region) in the constellation Monoceros. spans 1°. It is a telescope object, 6 inches or larger, and it is highest in the evening sky in February.

Nebula: a cloud of gas and dust. Emission nebulae glow on their own, lit by ultraviolet light from hot young stars; reflection nebulae shine by starlight scattered from dust; dark nebulae block the light behind them.

RCW 4 is RCW 4 in the RCW catalog of southern H-alpha regions

A. W. Rodgers, C. T. Campbell and J. B. Whiteoak listed it in their catalog of H-alpha emission regions in the southern Milky Way (1960), from photographs taken at Mount Stromlo Observatory.

Finding RCW 4 from Sirius

Sirius RCW 4 MONOCEROS

RCW 4 lies 12.5° northeast of Sirius, the magnitude -1.4 star. A fist held at arm's length covers about 10°.

RCW 4 is highest in the evening in February

JAN FEB MAR APR MAY JUN JUL AUG SEP OCT NOV DEC 60°N JAN at 60°N: 14° high at 9 pm FEB at 60°N: 21° high at 9 pm MAR at 60°N: 20° high at 9 pm APR at 60°N: 12° high at 9 pm MAY at 60°N: -1° high at 9 pm JUN at 60°N: -16° high at 9 pm JUL at 60°N: -29° high at 9 pm AUG at 60°N: -38° high at 9 pm SEP at 60°N: -37° high at 9 pm OCT at 60°N: -28° high at 9 pm NOV at 60°N: -13° high at 9 pm DEC at 60°N: 1° high at 9 pm 50°N JAN at 50°N: 21° high at 9 pm FEB at 50°N: 31° high at 9 pm MAR at 50°N: 30° high at 9 pm APR at 50°N: 18° high at 9 pm MAY at 50°N: 2° high at 9 pm JUN at 50°N: -18° high at 9 pm JUL at 50°N: -35° high at 9 pm AUG at 50°N: -47° high at 9 pm SEP at 50°N: -46° high at 9 pm OCT at 50°N: -33° high at 9 pm NOV at 50°N: -14° high at 9 pm DEC at 50°N: 5° high at 9 pm 40°N JAN at 40°N: 28° high at 9 pm FEB at 40°N: 40° high at 9 pm MAR at 40°N: 39° high at 9 pm APR at 40°N: 25° high at 9 pm MAY at 40°N: 4° high at 9 pm JUN at 40°N: -19° high at 9 pm JUL at 40°N: -41° high at 9 pm AUG at 40°N: -57° high at 9 pm SEP at 40°N: -55° high at 9 pm OCT at 40°N: -37° high at 9 pm NOV at 40°N: -15° high at 9 pm DEC at 40°N: 8° high at 9 pm 30°N JAN at 30°N: 35° high at 9 pm FEB at 30°N: 50° high at 9 pm MAR at 30°N: 48° high at 9 pm APR at 30°N: 30° high at 9 pm MAY at 30°N: 7° high at 9 pm JUN at 30°N: -19° high at 9 pm JUL at 30°N: -45° high at 9 pm AUG at 30°N: -66° high at 9 pm SEP at 30°N: -63° high at 9 pm OCT at 30°N: -41° high at 9 pm NOV at 30°N: -14° high at 9 pm DEC at 30°N: 11° high at 9 pm 20°N JAN at 20°N: 40° high at 9 pm FEB at 20°N: 59° high at 9 pm MAR at 20°N: 57° high at 9 pm APR at 20°N: 35° high at 9 pm MAY at 20°N: 9° high at 9 pm JUN at 20°N: -19° high at 9 pm JUL at 20°N: -47° high at 9 pm AUG at 20°N: -73° high at 9 pm SEP at 20°N: -69° high at 9 pm OCT at 20°N: -43° high at 9 pm NOV at 20°N: -14° high at 9 pm DEC at 20°N: 13° high at 9 pm 10°N JAN at 10°N: 45° high at 9 pm FEB at 10°N: 68° high at 9 pm MAR at 10°N: 65° high at 9 pm APR at 10°N: 39° high at 9 pm MAY at 10°N: 11° high at 9 pm JUN at 10°N: -19° high at 9 pm JUL at 10°N: -48° high at 9 pm AUG at 10°N: -78° high at 9 pm SEP at 10°N: -72° high at 9 pm OCT at 10°N: -43° high at 9 pm NOV at 10°N: -13° high at 9 pm DEC at 10°N: 16° high at 9 pm 0° JAN at 0°: 48° high at 9 pm FEB at 0°: 76° high at 9 pm MAR at 0°: 71° high at 9 pm APR at 0°: 42° high at 9 pm MAY at 0°: 13° high at 9 pm JUN at 0°: -17° high at 9 pm JUL at 0°: -46° high at 9 pm AUG at 0°: -75° high at 9 pm SEP at 0°: -70° high at 9 pm OCT at 0°: -42° high at 9 pm NOV at 0°: -12° high at 9 pm DEC at 0°: 18° high at 9 pm 10°S JAN at 10°S: 49° high at 9 pm FEB at 10°S: 79° high at 9 pm MAR at 10°S: 73° high at 9 pm APR at 10°S: 43° high at 9 pm MAY at 10°S: 14° high at 9 pm JUN at 10°S: -15° high at 9 pm JUL at 10°S: -43° high at 9 pm AUG at 10°S: -68° high at 9 pm SEP at 10°S: -64° high at 9 pm OCT at 10°S: -39° high at 9 pm NOV at 10°S: -10° high at 9 pm DEC at 10°S: 19° high at 9 pm 20°S JAN at 20°S: 48° high at 9 pm FEB at 20°S: 75° high at 9 pm MAR at 20°S: 70° high at 9 pm APR at 20°S: 43° high at 9 pm MAY at 20°S: 15° high at 9 pm JUN at 20°S: -13° high at 9 pm JUL at 20°S: -39° high at 9 pm AUG at 20°S: -59° high at 9 pm SEP at 20°S: -56° high at 9 pm OCT at 20°S: -35° high at 9 pm NOV at 20°S: -8° high at 9 pm DEC at 20°S: 20° high at 9 pm 30°S JAN at 30°S: 46° high at 9 pm FEB at 30°S: 66° high at 9 pm MAR at 30°S: 63° high at 9 pm APR at 30°S: 41° high at 9 pm MAY at 30°S: 16° high at 9 pm JUN at 30°S: -10° high at 9 pm JUL at 30°S: -33° high at 9 pm AUG at 30°S: -50° high at 9 pm SEP at 30°S: -48° high at 9 pm OCT at 30°S: -30° high at 9 pm NOV at 30°S: -6° high at 9 pm DEC at 30°S: 20° high at 9 pm 40°S JAN at 40°S: 42° high at 9 pm FEB at 40°S: 57° high at 9 pm MAR at 40°S: 55° high at 9 pm APR at 40°S: 38° high at 9 pm MAY at 40°S: 16° high at 9 pm JUN at 40°S: -8° high at 9 pm JUL at 40°S: -27° high at 9 pm AUG at 40°S: -40° high at 9 pm SEP at 40°S: -39° high at 9 pm OCT at 40°S: -24° high at 9 pm NOV at 40°S: -3° high at 9 pm DEC at 40°S: 19° high at 9 pm below horizon low 20-40° 40-60° overhead-ish

The chart gives its height above the horizon at 9 pm through the year, from 60°N to 40°S. It can be seen from the whole southern hemisphere and north to about 81°N.

The distance to RCW 4 is not well measured

Objects within 6° of RCW 4

RCW 4 catalog data

FieldValue
Typeemission nebula (H II region)
ConstellationMonoceros
Right ascension (J2000)07h 23.9m
Declination (J2000)-08° 36′
Apparent size1°
Best monthFebruary
Best withTelescope
RCW numberRCW 4