Messier 94
Characteristics:
Magnitude: 8.2
Size: approximately 10' (not considering outer halo)
Distance: 14.5 million light years
RA: 12h 50.9m
Dec: 41 degrees 07'
Description:
M94 is a face-on spiral galaxy in Canes Venatici. It was
discovered by Pierre Mechain in 1781, who then reported it to his
friend, Charles Messier. I decided to obtain a relatively deep
luminance exposure and combined the subs with the drizzle technique,
which brought out added detail best seen in the higher resolution view.
M94 has a distinct outer halo which is oval in shape and very obvious
in the above image. Additional information about M94
may be found here.
Photographic
Details:
Date: May 10,
2005
Scope: Takahashi
FS-102 at f6 with TOA-130 focal reducer, on the G11 Losmandy
Mount.
Autoguider: SBIG STV with
e-finder.
Camera: SXV-H9
Filter: Astronomik
clear filter.
Exposures: 30 x 5' each; Total
exposure duration 150 minutes.
Conditions: Temperature 55 degrees F; excellent
transparency; poor seeing; clear; slight breeze. A great night
with the smell of nearby cherry blossoms filling the air and a
sparkling stellar dome overhead.
Post-processing: No darks,
although bias-subtracted flats were used for this image.
Calibration done in ImagesPlus. I used the same procedure as for
my image of M63.
Drizzle combined with coefficient
sampling of 1.2 in IRIS.
DDP was
performed in ImagesPlus. Subsequent
levels and curves adjustments in Photoshop CS (16 bit format).
Final sharpening done with high pass filtering. I did not
dither the subs during image acquisition. The slight subpixel
drift between exposures appears to satisfy the needs of the drizzle
algorithm.
Please
note: Graphics on this website may not be reproduced without
author permission.
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