This is the Witch Head Nebula, so named because of its shape which takes on the profile of a cackling witch's face even down to the sinister hooked nose and pointy chin.  The nebula is classed as a reflection nebula reflecting the light from the blue super giant Rigel in Orion.  There is also a slight bit of emission nebulosity from hydrogen gas within the cloud and again irradiated by Rigel that adds a red tint to the blue reflected light giving the nebula its violet hue.

The nebula is very faint and large.  This image spans approximately 2.75 degrees of sky or almost six full moon widths from top to bottom.  South is generally up in this image so this image is upside down as normally seen in the night sky from the northern hemisphere.  Rigel, the bright blue star in the southwest corner of Orion is to the right of the nebula as shown here while east of the nebula in the night sky.  Rigel's solar winds are "blowing" the gas and dust of the cloud into the profile of the witches face and are also compressing the gases giving opportunities for star birth within the gas cloud.

The nebula is believed to be a supernova remnant of a long dead super giant star and lies in the constellation Eridanus, the River just west of Orion and Rigel.

AKA:  IC 2118, Cederblad 41