The Pleiades (M45)
Characteristics:
Magnitude: 1.6
Distance: 380 light years
RA: 3h 46m 31s
Dec: 23 degrees 57' 36"
Description:
The Pleiades (M45, the "Seven Sisters")
convey a sense of stately, quiet winter beauty. This open star
cluster has been recognized since antiquity, with the oldest recorded
observation being approximately 1000 years BC. Within this
cluster, it is possible to resolve between 7-11 stars with the naked
eye, depending upon seeing conditions (and eyesight!). Through
the telescope, the cluster is known to contain about 500 stars that are
gravitationally bound to each other. The age of this cluster is
estimated to be about 65 million years old, meaning that it was "born"
around the time of the dinosaur extinction. The beauty of this
cluster is due to the impressive amount of blue nebulosity that
surrounds many of the stars, most notably Merope (surrounded
by the brightest reflection nebulae of this group, NGC 1435). In
contrast to emission nebulae, the blue color of this nebula is due to
reflected light from nearby young stars. During visual
observation, there is a hint of nebulosity in a small scope such as an
8" SCT,
although the full extent can only be observed in longer exposure photos
such as this one. Please click here
for a higher resolution image.
Photographic Details:
Date: November 22, 2003
Scope: Takahashi Sky 90 at f4.5 with field flattener/focal
reducer, piggybacked on LX90 (which is mounted on a Meade Superwedge).
Autoguider: STV with e-finder.
Camera: Canon 10D.
Filter: IDAS LPS.
Exposures: 12 x 5' at ISO 800.
Conditions: Temperature 35 degrees F;
below average transparency; average seeing; very dewy; calm.
Post-processing: Raw
conversion, adaptive dark frame calibration, alignment, min/max
excluded averaging done in ImagesPlus; Levels, curves, and layer mask adjustments in Photoshop.
I was not satisfied with my initial processing, since
star coloration was washed out in the process of curves adjustment.
I
reprocessed this on 12/21/03 using a mask to protect the stars from
bloating
and color loss, resulting in a more pleasing image (also check high
resolution
link).
Please
note: Graphics on this website may not be reproduced without
author permission.
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