The sky around RCW 161, 4° across, north up M17 low-power eyepiece, 1° NE 1°
The sky around RCW 161 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 161

Emission nebula (H II region) in Serpens

Emission nebula (H II region) in Serpens.

SERPENS

The box shows where RCW 161 sits in Serpens.

Constellation
SerpensSer
Magnitude
-visual
Size
1.3°apparent
Distance
-light-years
Best month
Augustat 9 pm
Best with
Telescope

RCW 161 is an emission nebula (H II region) in Serpens

RCW 161 is an emission nebula (H II region) in the constellation Serpens. spans 1.3°. It is a telescope object, 6 inches or larger, and it is highest in the evening sky in August.

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 161 is RCW 161 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 161 from Sinistra

Sinistra RCW 161 SERPENS

RCW 161 lies 7.6° southeast of Sinistra, the magnitude 3.3 star. Three fingers held at arm's length cover about 5°.

RCW 161 is highest in the evening in August

JAN FEB MAR APR MAY JUN JUL AUG SEP OCT NOV DEC 60°N JAN at 60°N: -41° high at 9 pm FEB at 60°N: -45° high at 9 pm MAR at 60°N: -39° high at 9 pm APR at 60°N: -26° high at 9 pm MAY at 60°N: -12° high at 9 pm JUN at 60°N: 2° high at 9 pm JUL at 60°N: 12° high at 9 pm AUG at 60°N: 15° high at 9 pm SEP at 60°N: 10° high at 9 pm OCT at 60°N: -1° high at 9 pm NOV at 60°N: -15° high at 9 pm DEC at 60°N: -30° high at 9 pm 50°N JAN at 50°N: -49° high at 9 pm FEB at 50°N: -55° high at 9 pm MAR at 50°N: -46° high at 9 pm APR at 50°N: -29° high at 9 pm MAY at 50°N: -10° high at 9 pm JUN at 50°N: 8° high at 9 pm JUL at 50°N: 21° high at 9 pm AUG at 50°N: 25° high at 9 pm SEP at 50°N: 18° high at 9 pm OCT at 50°N: 4° high at 9 pm NOV at 50°N: -14° high at 9 pm DEC at 50°N: -33° high at 9 pm 40°N JAN at 40°N: -57° high at 9 pm FEB at 40°N: -65° high at 9 pm MAR at 40°N: -52° high at 9 pm APR at 40°N: -30° high at 9 pm MAY at 40°N: -8° high at 9 pm JUN at 40°N: 14° high at 9 pm JUL at 40°N: 29° high at 9 pm AUG at 40°N: 35° high at 9 pm SEP at 40°N: 27° high at 9 pm OCT at 40°N: 9° high at 9 pm NOV at 40°N: -13° high at 9 pm DEC at 40°N: -35° high at 9 pm 30°N JAN at 30°N: -62° high at 9 pm FEB at 30°N: -74° high at 9 pm MAR at 30°N: -57° high at 9 pm APR at 30°N: -31° high at 9 pm MAY at 30°N: -5° high at 9 pm JUN at 30°N: 19° high at 9 pm JUL at 30°N: 38° high at 9 pm AUG at 30°N: 45° high at 9 pm SEP at 30°N: 34° high at 9 pm OCT at 30°N: 14° high at 9 pm NOV at 30°N: -11° high at 9 pm DEC at 30°N: -36° high at 9 pm 20°N JAN at 20°N: -65° high at 9 pm FEB at 20°N: -83° high at 9 pm MAR at 20°N: -59° high at 9 pm APR at 20°N: -30° high at 9 pm MAY at 20°N: -3° high at 9 pm JUN at 20°N: 24° high at 9 pm JUL at 20°N: 46° high at 9 pm AUG at 20°N: 55° high at 9 pm SEP at 20°N: 42° high at 9 pm OCT at 20°N: 18° high at 9 pm NOV at 20°N: -9° high at 9 pm DEC at 20°N: -36° high at 9 pm 10°N JAN at 10°N: -64° high at 9 pm FEB at 10°N: -83° high at 9 pm MAR at 10°N: -58° high at 9 pm APR at 10°N: -28° high at 9 pm MAY at 10°N: -0° high at 9 pm JUN at 10°N: 28° high at 9 pm JUL at 10°N: 53° high at 9 pm AUG at 10°N: 65° high at 9 pm SEP at 10°N: 48° high at 9 pm OCT at 10°N: 22° high at 9 pm NOV at 10°N: -6° high at 9 pm DEC at 10°N: -35° high at 9 pm 0° JAN at 0°: -60° high at 9 pm FEB at 0°: -74° high at 9 pm MAR at 0°: -54° high at 9 pm APR at 0°: -26° high at 9 pm MAY at 0°: 3° high at 9 pm JUN at 0°: 32° high at 9 pm JUL at 0°: 59° high at 9 pm AUG at 0°: 75° high at 9 pm SEP at 0°: 53° high at 9 pm OCT at 0°: 26° high at 9 pm NOV at 0°: -4° high at 9 pm DEC at 0°: -32° high at 9 pm 10°S JAN at 10°S: -54° high at 9 pm FEB at 10°S: -64° high at 9 pm MAR at 10°S: -49° high at 9 pm APR at 10°S: -23° high at 9 pm MAY at 10°S: 5° high at 9 pm JUN at 10°S: 34° high at 9 pm JUL at 10°S: 63° high at 9 pm AUG at 10°S: 84° high at 9 pm SEP at 10°S: 57° high at 9 pm OCT at 10°S: 28° high at 9 pm NOV at 10°S: -1° high at 9 pm DEC at 10°S: -29° high at 9 pm 20°S JAN at 20°S: -47° high at 9 pm FEB at 20°S: -55° high at 9 pm MAR at 20°S: -43° high at 9 pm APR at 20°S: -19° high at 9 pm MAY at 20°S: 8° high at 9 pm JUN at 20°S: 36° high at 9 pm JUL at 20°S: 64° high at 9 pm AUG at 20°S: 84° high at 9 pm SEP at 20°S: 57° high at 9 pm OCT at 20°S: 30° high at 9 pm NOV at 20°S: 1° high at 9 pm DEC at 20°S: -24° high at 9 pm 30°S JAN at 30°S: -39° high at 9 pm FEB at 30°S: -45° high at 9 pm MAR at 30°S: -35° high at 9 pm APR at 30°S: -14° high at 9 pm MAY at 30°S: 10° high at 9 pm JUN at 30°S: 36° high at 9 pm JUL at 30°S: 61° high at 9 pm AUG at 30°S: 75° high at 9 pm SEP at 30°S: 56° high at 9 pm OCT at 30°S: 30° high at 9 pm NOV at 30°S: 4° high at 9 pm DEC at 30°S: -19° high at 9 pm 40°S JAN at 40°S: -30° high at 9 pm FEB at 40°S: -35° high at 9 pm MAR at 40°S: -27° high at 9 pm APR at 40°S: -10° high at 9 pm MAY at 40°S: 12° high at 9 pm JUN at 40°S: 35° high at 9 pm JUL at 40°S: 56° high at 9 pm AUG at 40°S: 65° high at 9 pm SEP at 40°S: 51° high at 9 pm OCT at 40°S: 30° high at 9 pm NOV at 40°S: 7° high at 9 pm DEC at 40°S: -14° 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 75°N, and never sets south of 75°S.

The distance to RCW 161 is not well measured

Objects within 6° of RCW 161

RCW 161 catalog data

FieldValue
Typeemission nebula (H II region)
ConstellationSerpens
Right ascension (J2000)18h 20.9m
Declination (J2000)-15° 08′
Apparent size1.3°
Best monthAugust
Best withTelescope
RCW numberRCW 161