Emission nebula · Cepheus

Sh2-155 Cave Nebula

Also known as: C9, LBN 529

mag 7.750′ across

About

Sh2-155, the Cave Nebula, is an emission nebula of magnitude 7.7 in Cepheus, about 50′ across.

Sh2-155 is in the constellation Cepheus.
Best evenings: around late October it is highest at about 9 pm (10 pm in summer time); a month earlier, two hours later.
Where on Earth: it is seen well, at least 10° up, from north of 17° S.

When it rises and sets tonight, how high it climbs and how much the Moon gets in the way are worked out in your browser for your place.

EyesNot visible to the naked eye.
Binoculars (10×50)A faint glow from a dark site; a nebula filter helps.
Telescope (6–8 inch)A faint glow — a UHC or OIII filter and a dark sky make the difference.

For a dark country sky with no Moon. From a city, faint galaxies and nebulae can disappear completely.

Designations	Sh2-155, C9, LBN 529
Type	Emission nebula
Magnitude	7.7The smaller the number, the brighter.
Apparent size	50′ × 30′position angle 90°; the full Moon is 31′ across
Constellation	Cepheus
Right ascension (J2000)	22h 57m 54.0s
Declination (J2000)	+62° 31′ 06″