M101
Characteristics:
RA (J2000): 14h 3m 10s
Dec (J2000): 54 degrees 21' 45"
Position Angle (Pinpoint): plus 0 degrees
Description:
M101 is a large, beautiful spiral galaxy in Ursa Major. For
visual observation, M101 is best seen using a low power eyepiece under
dark skies. Despite being relatively bright at magnitude 8.5, it
has low surface brightest due to its large size. There are many
smaller, faint galaxies in this FOV. More information about M101
may be found here.
Photographic
Details:
Dates: May 11, 13, 14,
2023.
Scope: Takahashi
FSQ106 at f5 on the Takahashi NJP
Mount.
Autoguider: ASI178 autoguider with SvBony 30mm guidescope, focal length
120mm.
Camera: ZWO ASI294MM at -10C,
with
7 position ZWO filter wheel. Pixel size is 2.3 microns (Bin 1x1),
yielding an image scale with the FSQ (530mm focal length) of 0.90
"/pixel (well matched for my seeing of 3 arcseconds).
Camera gain set to 50 (e-gain
2.13 electrons/ADU), offset 25.
Read noise at this gain level was 2.18 electrons rms.
Filters: Baader LUM,
R, G, B filters; 2 inch.
Image acquisition
software: MaximDL for camera control and autoguiding; CCD
Commander for automation.
Exposures: Total
exposure 11 hours (LUM: 5 hours, 60 second subs; RGB 6 hours, 120
second subs).
Processing:
Calibration, registration, local
normalization, cropping, dynamic background extraction,
BlurXterminator, NoiseXterminator, and histogram transformation in
Pixinsight; Subsequent LRGB processing in Photoshop.
Please
note: Graphics on this website may not be reproduced without
author permission.
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