The Pleiades (M45)
Distance: 380 light years
RA: 3h 46m 31s
Dec: 23 degrees 57' 36"
The beautiful Pleiades open star cluster (M45, the "Seven Sisters") 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
about 500 stars that are gravitationally bound to each other.
age of this cluster is estimated to be about 65 million years old,
that it was "born" around the time of the dinosaur extinction.
beauty of this cluster is due to the impressive amount of blue
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 on the following
link to observe a higher
Dates: September 29, 2003 (Merope region) and October 6,
2003 (5 additional regions to complete the mosaic)
Scope: LX90 at f6.3, Lumicon OAG
Autoguider: SBIG STV with e-finder
Camera: Canon 10D
Filter: IDAS LPS
Exposures: 30 exposures x 6 to 9 minutes each at ISO1600.
Total exposure time 3.5 hours.
49 degress F; average transparency; average seeing; wind minimal
(September 29). Temperature 39 degrees F on October 6.
Post-processing: This represents
a mosaic of a total of 6 different sections of M45 (each section is an
average stack of 5 frames). The frames for each section were
processed as follows: raw conversion, adaptive dark frame
calibration, alignment, autograding, min/max excluded averaging, and
background compensation done in ImagesPlus; levels and curves
adjustment in Photoshop; final smoothing done in Pleiades SGBNR
software. Mosaic was constructed in Photoshop using the technique
described by Rob Gendler. Total processing time was
approximately 20 hours over a period of 3 days.
note: Graphics on this website may not be reproduced without
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