Size: Roughly 3 degrees across.
Distance: 2,450 light years
RA: 21h 39m 31s (J2000)
Dec: 57degrees 29' 59" (J2000)
IC1396 is a large emission nebula in Cepheus. The above image was
obtained using two different kinds of narrowband filters: one
that passes light emitted from singly
ionized hydrogen (HII), and another that passes light from doubly
ionized oxygen (OIII). Both hydrogen and oxygen are ionized as a
result of UV irradiation from the central
star HD206267. Radiation from this star has cleared out a central
portion from the nebula and has also blown away gas and dust radially,
resulting in a variety of dark globules that roughly point towards the
center. These are called "cometary globules"
in recognition of their overall shape, which consists of a head
followed by a tail of dust that is being blown backwards by HD206267's
solar wind. The most conspicuous globule is 1396A, also known as
the "Elephant Trunk,"
which contains a subtle reflection nebula vdb142.
Other cometary globules can be appreciated in the 60% size
hydrogen alpha version of this image. Although
the dark gas and
dust are opaque to visible light, infrared light passes through this
region easily, permitting a view of the inner workings of the Elephant
Trunk. Please click here
for an infrared view of this area taken through the Space InfraRed
Telescope Facility (SIRTF), now known
as the Spitzer Space Telescope. Please be sure to check out
the larger sized images for greater detail. Rob
Gendler has an excellent
description of IC1396 on his website.
Date Posted: June 9, 2007
FSQ106 at f5 on the G11 Losmandy
Autoguider: SBIG ST-402 with
Camera: STL11K -20C.
Filters: Baader 7 nm
Ha filter; Baader 8.5 nm OIII filter.
Exposures: Ha, 10
x 20'; OIII, 8 X 15' (unbinned,
exposure 5.3 hours.
Calibrated, astrometric aligned, and Sigma
in Maxim, followed
in ImagesPlus (IP). Further processing in Photoshop CS (16
bit format). The Ha and OIII images were combined using my Bicolor
note: Graphics on this website
may not be reproduced without author permission.
Back to Nebulae