Witch Head Nebula (IC 2118)
Characteristics:
FOV: Approximately 6 x 6
degrees
RA (J2000): 05h 09m 48s
Dec (J2000): Minus 08 degrees 18' 31"
Position Angle: 179 degrees
Description:
This is a 5 hour exposure of the Witch Head Nebula (IC2118), a large
and very faint reflection nebula in the constellation Eridanus, taken
through the Samyang 135mm f2.0 lens (stopped
down to f3.1 using step down rings) and a full-spectrum modified Canon
T7i DSLR. The nebula is located left of center, and Rigel is the bright
star located right of center. The molecular
cloud that forms this nebula contains carbon monoxide, which is a
surrogate marker of molecular hydrogen and a characteristic of stellar
nurseries such as those common in the Orion OB1 complex.
Although IC2118 is a reflection nebula
that is often
portrayed as more blue in color due to preferential scattering of blue
light by dust particles within the molecular cloud, in my image the
nebula clearly has a reddish hue. In
my location in a suburb of Boston, MA,
IC2118 was as low as 26 degrees at the start of
the session and rose to only 40
degrees altitude during this image.
Thus, I suspect that the low altitude of
this target in my location has resulted in
atmospheric extinction of blue light, with relative enhancement of
red and, to a lesser extent, green light. More information about
this
region can be found on
Rob
Gendler's website.
Photographic Details:
Dates: November 28, 2022.
Scope: Samyang 135mm f2.0 prime lens on the
Skywatcher Star Adventurer portable tracker.
Autoguider: ASI178M with the
SvBony 30mm guidescope (focal length 120mm, f4). PhD2 was used
for guiding.
Camera: Self-modified Canon T7i (full spectrum).
Filters: Astronomik
CLS-CCD clip on EOS filter.
Exposures: 60 second subs for a
total of 5 hours data.
Processing:
PixInsight for Preprocessing (WBPP and NSG
scripts)
. Photoshop for Postprocessing.
Please
note: Graphics on this website may not be reproduced without
author permission.
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