Messier 101
| Optics |
TEC 140APO with Flattener at f7.2 |
| Mount |
AstroPhysics 900GoTo |
| Camera |
STL11000M |
| Filters |
Baader LHaRGB |
| Date |
February-May 2012 |
| Location |
Antares Observatory |
| Sky Conditions |
mag 5 sky |
| Exposure |
LHaRGB = 24.3,5.3,5.8,4.7,5.5h
total: 45.6h |
| Programs used |
PixInsight, Photoshop CS4 |
| Notes |
First light of TEC140APO |
My goal with this image was to show the extremely faint outer spiral arms of Messier 101. A master Luminance
channel was created using all the luminance and color filtered images. The resulting image includes more than 40
hours of data. All frames were captured at a time when M101 was near the zenith in order to keep the atmospheric extinction
and effects from light pollution as low as possible. Click on the thumbnails below to find some crops in 100% and
150% resolution:
An interesting feature is visible around NGC5485. Up to now it is not clear if the stellar-stream-looking
structure is really associated with the NGC5485 or if it is a foreground nebula. If you have any information
regarding this object, please drop me an email! Below you find an inverted image
from luminance dat at 100% resolution showing the circular stellar stream candidate around NGC5485 and an
additional possible associated structure to the left. North is to the right.
click here for a 70% size image, 2764x1824 (3262KB)
The total luminance image (2410 minutes) is shown below on the left and an inverted image for better visibility
of the faint outer spiral arms is shown on the right side. Click on each to find a larger version.
Beside the faint spiral arms a faint background nebula is visible. This galactic cirrus becomes prominent when the image contrast
is strongly enhanced. This however also enhances possible image calibration errors (i.e. flat field calibration).
Although image calibration and background correction was done very carefully, some of the structures might still
be due to bad image calibration. A comparison of the IRAS survey images (low resolution) however confirms most of
the structures seen here.
