RCW 157 is an emission nebula (H II region) in Sagittarius
RCW 157 (IC 4701, LBN 55, Ced 158) is an emission nebula (H II region) in the constellation Sagittarius . spans 1°. 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.
Finding RCW 157 from Kaus Borealis
Kaus Borealis
RCW 157
SAGITTARIUS
RCW 157 lies 9.0° north of Kaus Borealis , the magnitude 2.8 star. A fist held at arm's length covers about 10°.
RCW 157 is highest in the evening in August
JAN
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APR
MAY
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AUG
SEP
OCT
NOV
DEC
60°N
JAN at 60°N: -43° high at 9 pm FEB at 60°N: -47° high at 9 pm MAR at 60°N: -41° high at 9 pm APR at 60°N: -27° high at 9 pm MAY at 60°N: -13° high at 9 pm JUN at 60°N: 1° high at 9 pm JUL at 60°N: 10° high at 9 pm AUG at 60°N: 13° high at 9 pm SEP at 60°N: 8° high at 9 pm OCT at 60°N: -2° high at 9 pm NOV at 60°N: -17° high at 9 pm DEC at 60°N: -31° high at 9 pm 50°N
JAN at 50°N: -51° high at 9 pm FEB at 50°N: -56° high at 9 pm MAR at 50°N: -47° high at 9 pm APR at 50°N: -29° high at 9 pm MAY at 50°N: -11° high at 9 pm JUN at 50°N: 7° high at 9 pm JUL at 50°N: 19° high at 9 pm AUG at 50°N: 23° high at 9 pm SEP at 50°N: 16° high at 9 pm OCT at 50°N: 3° high at 9 pm NOV at 50°N: -16° high at 9 pm DEC at 50°N: -35° high at 9 pm 40°N
JAN at 40°N: -58° high at 9 pm FEB at 40°N: -66° high at 9 pm MAR at 40°N: -53° 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: 13° high at 9 pm JUL at 40°N: 28° high at 9 pm AUG at 40°N: 33° high at 9 pm SEP at 40°N: 25° high at 9 pm OCT at 40°N: 8° high at 9 pm NOV at 40°N: -14° high at 9 pm DEC at 40°N: -37° high at 9 pm 30°N
JAN at 30°N: -64° high at 9 pm FEB at 30°N: -76° 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: 37° high at 9 pm AUG at 30°N: 43° high at 9 pm SEP at 30°N: 32° high at 9 pm OCT at 30°N: 12° high at 9 pm NOV at 30°N: -12° high at 9 pm DEC at 30°N: -38° high at 9 pm 20°N
JAN at 20°N: -66° high at 9 pm FEB at 20°N: -84° high at 9 pm MAR at 20°N: -58° high at 9 pm APR at 20°N: -30° high at 9 pm MAY at 20°N: -2° high at 9 pm JUN at 20°N: 24° high at 9 pm JUL at 20°N: 45° high at 9 pm AUG at 20°N: 53° high at 9 pm SEP at 20°N: 40° high at 9 pm OCT at 20°N: 17° high at 9 pm NOV at 20°N: -10° high at 9 pm DEC at 20°N: -37° high at 9 pm 10°N
JAN at 10°N: -65° high at 9 pm FEB at 10°N: -81° high at 9 pm MAR at 10°N: -57° 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: 29° high at 9 pm JUL at 10°N: 53° high at 9 pm AUG at 10°N: 63° high at 9 pm SEP at 10°N: 46° high at 9 pm OCT at 10°N: 21° high at 9 pm NOV at 10°N: -8° high at 9 pm DEC at 10°N: -36° high at 9 pm 0°
JAN at 0°: -60° high at 9 pm FEB at 0°: -72° high at 9 pm MAR at 0°: -53° high at 9 pm APR at 0°: -25° 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°: 73° high at 9 pm SEP at 0°: 52° high at 9 pm OCT at 0°: 24° high at 9 pm NOV at 0°: -5° high at 9 pm DEC at 0°: -33° high at 9 pm 10°S
JAN at 10°S: -54° high at 9 pm FEB at 10°S: -63° high at 9 pm MAR at 10°S: -47° high at 9 pm APR at 10°S: -21° high at 9 pm MAY at 10°S: 6° high at 9 pm JUN at 10°S: 35° high at 9 pm JUL at 10°S: 64° high at 9 pm AUG at 10°S: 82° high at 9 pm SEP at 10°S: 56° high at 9 pm OCT at 10°S: 27° high at 9 pm NOV at 10°S: -2° high at 9 pm DEC at 10°S: -29° high at 9 pm 20°S
JAN at 20°S: -46° high at 9 pm FEB at 20°S: -53° high at 9 pm MAR at 20°S: -41° high at 9 pm APR at 20°S: -17° high at 9 pm MAY at 20°S: 9° high at 9 pm JUN at 20°S: 37° high at 9 pm JUL at 20°S: 65° high at 9 pm AUG at 20°S: 85° high at 9 pm SEP at 20°S: 57° high at 9 pm OCT at 20°S: 29° 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: -37° high at 9 pm FEB at 30°S: -43° high at 9 pm MAR at 30°S: -33° high at 9 pm APR at 30°S: -13° high at 9 pm MAY at 30°S: 11° high at 9 pm JUN at 30°S: 38° high at 9 pm JUL at 30°S: 63° high at 9 pm AUG at 30°S: 76° 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: -29° high at 9 pm FEB at 40°S: -33° high at 9 pm MAR at 40°S: -25° high at 9 pm APR at 40°S: -8° high at 9 pm MAY at 40°S: 13° high at 9 pm JUN at 40°S: 37° high at 9 pm JUL at 40°S: 57° high at 9 pm AUG at 40°S: 67° high at 9 pm SEP at 40°S: 52° 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: -13° 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 73°N, and never sets south of 73°S.
The distance to RCW 157 is not well measured
Objects within 6° of RCW 157
RCW 156, emission nebula (H II region), 42′ M18, open cluster, 44′ M17 Omega Nebula, diffuse nebula, 1.1° RCW 155, emission nebula (H II region), 1.5° M24 Small Sagittarius Star Cloud, cloud, 1.7° RCW 159, emission nebula (H II region), 1.9° RCW 161, emission nebula (H II region), 1.9° RCW 153, emission nebula (H II region), 2.7°
RCW 157 catalog data
Field Value
Designations IC 4701, LBN 55, Ced 158 Type emission nebula (H II region) Constellation Sagittarius Right ascension (J2000) 18h 17.2m Declination (J2000) -16° 48′ Apparent size 1° Best month August Best with Telescope RCW number RCW 157
