|
|
Click the image for a higher
resolution
view. (2100 x 1400 - 1.12 MB)
|
Instrument |
12.5" RCOS @
~f/9 (2880 mm fl) at 0.64 arcsec/pixel. Shown at 2.77 and 0.99 arcsec/pixel. |
|
Mount |
Paramount ME |
|
Camera |
SBIG STL-11000 w/
FW8 filter wheel, AstroDon Gen-2 Filters |
|
Acquisition Data |
10/21/2014
to 11/27/2014 Chino Valley, AZ... with CCDAutoPilot, CCD Commander & CCDSoft,
AOL guided. |
|
Exposure |
|
Lum |
360 min. (24 x
15 min.) Bin 1x1 |
|
RGB |
810 min. (18 x 15 min.
each) Bin 2x2 |
|
|
Software & Processing Notes |
-
CCDSoft, CCDStack,
PixInsight & Photoshop CS6.
-
eXcalibrator
v4.25 for (g:r) color balancing, using 50 stars from the
SDSS-DR9 database.
-
CCDBand-Aid to repair
KAI-11000M vertical bars.
-
CCDStack to
calibrate the sub
exposures.
-
PixInsight
processing includes sub exposure registration and stacking, RGB
creation, gradient repair and non-linear stretching with HistogramTransformation.
Selective use of HDRMultiscaleTransform, with various layer
counts, was used to individually enhance the detail of the four
galaxies.
-
PhotoShop for
combining the images with varying galaxy detail, creating the
LRGB and final touch up.
|
|
Comment |
The image is shown
with north to the top.
This field of view, in
the constellation Aries, is a great example of galaxy diversity.
From left to right, the galaxies are ARP 31, NGC 691, NGC 680 and
NGC 678. Their respective distances from Earth are 118, 106, 118 and
113 million light years.
ARP 31 is in an irregular barred spiral galaxy with only two arms.
NGC 691 is a smoother than normal face on Sc spiral galaxy. NGC 680
is an asymmetrical elliptical that also shows the characteristics of
a shell galaxy. Deeper exposures revealed two tidal tales with one
extending towards the nearby galaxy, NGC 678. This suggests that the
two are an interacting pair. Finally, NGC 678 is an edge view of an
SBb spiral galaxy with an interesting dust lane. |
|
