Messier 91 (M91) & NGC 4571
Also Known as: NGC 4548 (M91), IC 3588 (NGC 4571)
Object Type: Barred Spiral Galaxy
Constellation: Coma Berenices
Distance from Earth: 63 million light years (M91), 58 million light years (NGC 4571)
Apparent Magnitude: 11.0 (M91), 11.8 (NGC 4571)
Coordinates: RA 12H 35M 26.4S DEC 14deg 35min 26.4sec (M91), RA 12H 36M 56.4S DEC 14deg 13min 02 (NGC 4571)sec
Actual Size: 100,000 light years in diameter (M91)
Apparent Dimensions: 5.4 arc-minutes x 4.3 arc-minutes (M91), 3.6 arc-minutes x 3.2 arc-minutes (NGC 4571)
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Environmental Data
Date: May 22, 2024 Start Time: 8:56PM End Time: 1:41AM SQM: 15.44
Moon Age: 13.9 days Moonrise: 7:34PM Moon Illumination: 99.1%
Temperature: 62 degrees F Humidity: 99% Dew Point: 62 degrees F
Location: Westport, Massachusetts 02790 Sky Condition: Murky
Comment: Very bright Moon after 9PM. Sky bright and mirky. Started only a few minutes prior to meridian flip.
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Imaging Scope Data
Mount: iOptron CEM120 Camera: ZWO ASI2600 OSC Focuser: Optec QuickSync FT20
Telescope: Celestron 11 inch SCT Edge Focal Length: 1960mm
Focal Reducer/Field Flattener: 0.7 focal reducer Filter: None
Rotator: Pegasus Falcon Rotator Power Control: Pegasus Ultimate Powerbox V2 Dew Heater: Kendrick dew strip
Imaging Software
Mount: iOptron Commander Focuser: Optec FocusLynx Commander
Imaging: Sequence Generator Pro Platesolve: ASTAP Rotator/Control: Pegasus Unity Platform
Imaging Status
Imaging Software: Sequence Generated Focus HFR 3.74 Platesolve: Good on 2nd attempt
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Guide Scope Data
Telescope: Stellarvue SV90 refractor Camera: ZWO ASI290 Focuser: Optec DirectSync SVX30
Dew Heater: Kendrick dew strip Software: PHD2 Exposure: 1-2 sec Binning: 1x1 Tracking Result: 0.65 arc-seconds RMS
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Images Taken
Number of light frames: 129 Duration: 2 minutes Gain: 100
Camera Temperature: -10 degrees C Binning: 1x1 F-Stop: 7.0
Total Integration Time: 4.3 hours
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Number of flat frames: 50 Duration: 0.05 seconds Gain: 100
Camera Temperature: -10 degrees C Binning: 1x1 F-Stop: 7.0
Flat Field Illumination: All-Pro 'Spike-a-Flat Field standard' illuminated panel
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Number of Dark frames: 50 (from library) Duration: 2 minutes Gain:U100
Camera Temperature: -10 degrees C Binning: 1x1 F-Stop: 7.0
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Number of Bias frames: 50 (from library) Duration: 0.001 seconds Gain: 100
Camera Temperature: -10 degrees C Binning: 1x1 F-Stop: 7.0
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Imaging Processing
Imaging Processing Software: PixInsight
Processes utilized: Linear - calibration/integration: Flats ImageCalibration with Master Bias, Flat ImageIntegration, Images ImageCalibration with Flat Master & Dark Master, Debayer, SubFrameSelector, StarAlign, ImageIntegration
Linear - Background extraction, Color correction, deconvolution, noise reduction: GradientCorrection, AutoColor, BlurXTerminator, NoiseXterminator
Non-Linear: GeneralizedHyperbolicStretch script, CurvesTransformation, MultiscaleLinearTransform for smoothing, HistogramTransformation
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Notes:
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