NGC 4725, NGC 4712, NGC 4747
Also Known as: UGC 7989, PGC 43451 (NGC 4725), UGC 7977 (NGC 4512), UGC 8005, PGC 43586 (NGC 4747)
Object Type: Intermediate Spiral Galaxy (NGC 4725), Spiral Galaxy (NGC 4712), Barred Spiral Galaxy (NGC 4747)
Constellation: Coma Berenices
Distance from Earth: 40 million light years (NGC 4725), 224 million light years (NGC 4712), 32 million light years (NGC 4747)
Apparent Magnitude: 10.1 (NGC 4725), 13.5 (NGC 4512), 12.4 (NGC 4747)
Coordinates: RA 12H 50M 26.56S DEC 25 deg 30 min 02.74 sec (NGC 4725), RA 12H 49M 33S DEC 25 deg 28 min 11 sec (NGC 4712), RA 12H 51M 45.9S DEC 25 deg 46 min 37 sec (NGC 4747)
Actual Size: 150,700 light years in diameter (NGC 4725), 35,000 light years in diameter (NGC 4747)
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Environmental Data
Date: April 28 & April 30 2025 Start Time: 8:54 PM (April 28) 8:59 PM (April 30) End Time: 11:50 PM (April 28), 2:24AM (April 30) SQM: 17.06 (April 28)
Moon Age: 1.1 days (April 28) 3.5 days (April 30) Moonset: 9:18PM (April 28) 11:51PM (April 30) Moon Illumination: 1.4% (April 28) 13.1% (April 30)
Temperature: 57.4 degrees F (April 28) 61 Degrees (April 30) Humidity: 48% (April 28) 39% (April 30) Dew Point: 37.9 degrees F (April 28) 36 degrees (April 30)
Location: Westport, Massachusetts 02790 Sky Condition: Scattered clouds. Heavy at ~11:50PM (April 28)
Comment:
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Imaging Scope Data
Mount: iOptron CEM120 Camera: ZWO ASI2600 monochrome Focuser: Optec QuickSync FT20
Telescope: Celestron 11 inch SCT Edge Focal Length: 1960mm
Focal Reducer/Field Flattener: 0.7 focal reducer Dew Heater: Kendrick dew strip
Filter Wheel : ZWO EFW 7 position 2 inch Filter(s): Baader Lum CMOS optimized 2 inch, Baader RED CMOS optimized 2 inch, Baader GREEN CMOS optimized 2 inch, Baader BLUE CMOS optimized 2 inch
Rotator: Pegasus Falcon 2 Power Control: Pegasus Ultimate Powerbox V2
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 2.78 (Red) (April 28) HFR 4.88 April 30 Platesolve: Success on 2nd attempt
Guide Scope Data
Telescope: Stellarvue SVX130 refractor Camera: ZWO ASI290 Focuser: Optec DirectSync SV35
Dew Heater: Kendrick dew strip Software: PHD2 Exposure: 3 sec Binning: 1x1 Tracking Result: 0.55 arc-seconds RMS (April 28), 0.85 arc-seconds RMS (April 30)
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Images Taken
Number of light frames (LUM): 37 (April 28) 41 (April 30) Duration: 2 minutes Gain: 100
Number of light frames (Red): 37 (April 28) Duration: 2 minutes Gain: 100
Number of light frames (Green): 35 (April 30) Duration: 2 minutes Gain: 100
Number of light frames (Blue): 35 (April 30) Duration: 2 minutes Gain: 100
Camera Temperature: 0 degrees C Binning: 1x1 F-Stop: 7.0
Total Integration Time: 6.17 hours
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Number of flat frames (LUM): 40 Duration: 0.022 Gain:100
Number of flat frames (Red): 40 Duration: 0.072 Gain: 100
Number of flat frames (Green): 40 Duration: 0.047 Gain: 100
Number of flat frames (Blue): 40 Duration: 0.094 Gain: 100
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: 100
Number of Bias frames: 50 (from library) Duration: 0.001 seconds Gain: 100
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Imaging Processing
Imaging Processing Software: PixInsight
Processes utilized: Linear - calibration/integration:
For each of the LUM, RED, GREEN, and BLUE lights: Flats ImageCalibration with Master Bias, Flat ImageIntegration, Images ImageCalibration with Flat Master & Dark Master, SubFrameSelector
StarAlign all calibrated lights using best LUM image as reference, ImageIntegration of each of the LUM, RED, GREEN, and BLUE sets
Linear - Background extraction, Color correction, deconvolution, noise reduction:
LUM GradientCorrection, BlurXTerminator, NoiseXterminator
RED/GREEN/BLUE GradientCorrection, LRGBCombination to create color image using only Red/Green/Blue, ImageSolve, SpectroPhotometricColorCalibration, BlurXTerminator, NoiseXterminator
Non-Linear:
LUM: GeneralizedHyperbolicStretch script, MultiScaleLinearTransform to sharpen, CurvesTransformation
COLOR: GeneralizedHyperbolicStretch script, CurvesTransformation for saturation, HistogramTransformation
ImageBlend script to combine LUM and COLOR masters, CurvesTransformation for Saturation, DynamicCrop.
Notes: Autoguider needed refocusing at ~ 1AM (April 30)
Click Below Image for Full Size:
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