NGC 7331 ~ Deer Lick Group
| Optics: |
Ritchey–Chrétien 20" F/8.2 (4166mm FL) |
Processing: |
PixInsight, Photoshop |
| Camera: |
SBIG STXL-11000 with Adaptive Optics |
Date: |
2014 Á 2020 |
|
11 Megapixel (4008 x 2672 16-bit sensor) |
Location: |
Columbus, Texas |
| Exposure: |
LRGB = 1600:160:160:180 minutes |
Imager: |
Kent E. Biggs |
NGC 7331 is the flagship galaxy in a group of visually
associated galaxies call the NGC 7331 group or “The Deer Lick
Group.” The name “Deer Lick” is attributed to author,
photographer and amateur astronomer, Tomm Lorenzin who named it
such in honor of an extremely fine night of viewing this group
of galaxies at Deer Lick Gap in the North Carolina mountains.
NGC 7331, also cataloged as
Caldwell 30, is about 40 million
light-years
away in the direction of the constellation
Pegasus, the white winged horse of Greek mythology.
It is only a coincidence that visually places NGC 7331 with the
other member galaxies of this group including NGC 7335, 7336,
7337, and 7340. All of these visually smaller galaxies are
nearly 8 times further way placing them somewhere between 290 to
370 million light-years! This makes all the galaxies comparable
in size to NGC 7331 even though they appear smaller. Some have
compared the visually larger NGC 7331 to our own
Milky Way
galaxy in both mass and appearance. However, while it may indeed
have similar mass and star count, NGC 7331 is an
unbarred spiral galaxy, whereas our Milky Way is a
barred spiral galaxy making our galaxy more similar to NGC
7337 in this image (above and left of center of NGC 7331 as
annotated in the image above). NGC 7336 in the image is also a
barred spiral, however the other galaxies in the group appear to
all be unbarred spiral or elliptical galaxies. All of these
galaxies including NGC 7331 contain from 100 to 300 billion or
more stars.
William
Herschel discovered NGC 7331 in 1784. While NGC 7331 is
likely circular or slightly elliptical in shape, it is
relatively flat and, like a dinner plate tilted toward us, nearly
edge-on from our point of view. Nevertheless, its spectacular spiral arms of mostly
white and bluish white stars are beautiful both visually and
photographically. What makes NGC 7331 a bit unusual is that in
most galaxies the central nucleus of stars and surrounding disk
rotates with the rest of the galaxy, however measurements of
spectra shifts the central region of NGC 7331, show it to be
rotating in the opposite direction compared to the outer spiral
arms. NGC 7331 is home to several
supernovae
recorded throughout the 1900’s and early 2000’s.
Note in
the insets above, several of the galaxies have been enlarged to
see more detail. Click on the image to see a full screen and
zoomable image. In the lower left portion of the image is
annotated 3 very distant galaxies much further than the 40
million light years to NGC 7331, and even much further than the
300 million or so light years to the other background galaxies
visible here.
The below image shows the same NGC 7331
group but without stars. Every star visible in the image above
is in our own Milky Way galaxy, but when they are removed using
AI algorithms, hundreds of other very faint galaxies become more
visible, some as far as a billion light-years way or further!
This is nearly 10 percent to the edge of the
observable universe, that part of the universe that expands
away from us at sub-light speeds. According to physics, nothing
can travel faster than light, but because of the way the
universe seems to expand proportionally to the distance between
objects, about 99.9% of objects in our universe are now
traveling away from us at speeds faster than light and therefore
will never be observable by humans. In other words, the universe
is about 1000 times bigger than we can every see!
NGC 7331 without Stars!
The image below shows a zoomed in view of the NGC 7331 group.
The image below shows a brightened view of the NGC 7331 group Note the additional dust and gas visisble, some of it between galaxies and others in our own galaxy.
NGC 7331 Zoomed In
The images below are older images processed with my Generaion 0 and Generation 1 processing techniques. The bottom image was taken with the previous generation 3.4 megapixel camera.
NGC 7331 ~ The Milky Way's Twin?
| Optics: |
RC Optical System 20" F/8.2 (4165.6 mm Focal Length) |
Date: |
June-August 2020 |
| Camera: |
SBIG STXL-11000 with AO-X Adaptive Optics |
Location: |
Columbus, Texas |
| Exposure: |
LRGB = 820:80:80:100 minutes |
Imager: |
Kent E. Biggs |
NGC 7331 is an
unbarred spiral galaxy about 40 million light years away in the
direction of the constellation Pegasus, the winged horse of
ancient Greek mythology. The words "in the direction of" is used
here, since no astronomical object is ever really "in" a
constellation. Constellations are made up collections of stars
by humans that are as fleeting as cloud shapes on an
astronomical scale. NGC 7331 appears to be surrounded by a group
of galaxies, but all of the other galaxies highlighted in this
image are much much further away at 300 and 400
million light years distant. Hovering over the image will show
the names of the other brighter galaxies in this image. Until
the early 2000s, it was believed that NGC 7331 was very
similar to our own Milky Way galaxy and hence called its twin.
However, discoveries have proven that our galaxy, although
similar in size and number of stars, is actually a barred spiral
galaxy that has a bar structure running through the center. NGC
7331 cleary has no bar and is therefore different from our own
galaxy. One interesting observation about NGC 7331 is that if
you look closely enough you will see that the center core of the
galaxy is not perfectly centered, as it favors the left side in
this image. Furthermore, it appears slightly inclined compared to the
disk of the entire galaxy. Amazing enough, this central disk is
actually rotating in the opposite direction of the galaxy, a
mystery among many others about the nature of galaxy formation
and their behaviors.
NGC 7331 - Earlier Imaging and Gen1 Processing.
| Optics: |
RC Optical System 20" F/8.2 (4165.6 mm Focal Length) |
Date: |
October 2010 |
| Camera: |
SBIG ST10XME with Adaptive Optics |
Location: |
Columbus, Texas |
| Exposure: |
LRGB = 400:120:80:120 minutes |
Imager: |
Kent E. Biggs |
NGC 7331 is one of
the most impressive spiral galaxies in the sky. It is the
brightest galaxy not to be included in the famous Messier
catalog of 100+ objects familiar to most amateurs. Some refer to
this galaxy as our own Milky Way Galaxy's twin due to its
appearance, but recent research suggests that our galaxy is
actually a barred spiral. NGC 7331 is often called the Deer Lick
Group named by Tomm Lorenzin coinciding with his best view of
the group during a trip to the Deer Lick Gap in the Smokey
Mountains. At 40-50 million light years, NGC 7331 is moving away
from us at over 500 miles per second and is slightly larger than
our own galaxy. The "smaller" galaxies in the image are far in
the distant and probably of similar size and mass to this
galaxy. The stats for this galaxy are RA: 22h 37m 04.5s, Dec:
+34° 25' 00", Mag: 9.4 (V), Size: 14.5'x3.7', Class: SA(s)b.