Galaxies
The Whirlpool Galaxy
The Whirlpool Galaxy (Messier 51) and companion NGC 5195 in Canes Venatici, photographed by Pete Lawrence – published in BBC Sky at Night.
Target details
The Whirlpool Galaxy (Messier 51a, NGC 5194) is a spiral galaxy in Canes Venatici, between 15 and 35 million light-years away, and was the first galaxy to be recognised as a spiral. It's interacting with its smaller companion, NGC 5195, and has an active core of the type called Seyfert 2. The pair are easy to find, even in binoculars, and professional astronomers study them closely to understand spiral arms and how galaxies affect each other.
This image was published in the Hotshots section of BBC Sky at Night magazine, June 2018. It was the first image of mine that was published.
Capture details
Data captured 20th & 21st March, 2018.
32x 3 minute exposures with Blue filter (Binned 2x2).
28x 3 minute exposures with Green filter (Binned 2x2).
30x 3 minute exposures with Red filter (Binned 2x2).
137x 3 minute exposures with Luminance filter.
Total Exposure = 11.3 hours.
Equipment details
Skywatcher Quattro 200 CF
NEQ6 Pro
Atik 428EX Mono
Skywatcher ST-80
QHY5L-II
Processing details
This image was processed in Pixinsight & Lightroom.
Calibration and Stacking in Pixinsight using Batch PreProcessing
Dynamic Crop - To remove black edges & integration artifacts. (Each Channel)
Automatic Background Extraction - To remove gradients. (RGB & Lum separately)
Channel Combination - To combine RGB channels.
Background Neutralisation - To neutralise background.
Colour Calibration - To calibrate colours.
SCNR - To remove green cast.
Deconvolution - To bring out some fine detail & tighten stars, 50 iterations. (Luminance only)
Multiscale Linear Transform - Noise reduction. (RGB & Lum separately)
Histogram Transformation - To stretch the RGB & Lum. (Using statistics process to keep background levels evenly)
LRGB Combination - To blend my luminance image with my RGB image.
Histogram Transformation - To clip blacks.
UnsharpMask - To sharpen with mask in place to exclude stars & background.
Curves Transformation - To boost contrast.
TVGDenoise - To denoise background, with previous sharpening mask in place but inverted.
Morphological Transformation: Erosion - To reduce stars slightly.
Clonestamp - To remove two large dust donuts.
Export as JPEG and import into Lightroom.
Increase Saturation (+15)
Export final JPEG for upload.
Quick facts
- What is The Whirlpool Galaxy?
- The Whirlpool Galaxy (Messier 51a, NGC 5194) is a spiral galaxy in Canes Venatici, between 15 and 35 million light-years away, and was the first galaxy to be recognised as a spiral. It's interacting with its smaller companion, NGC 5195, and has an active core of the type called Seyfert 2.
- Where is it in the sky?
- In the constellation Canes Venatici.
- What are its catalogue names?
- NGC 5194, NGC 5195
- When was this photo taken?
- 21 March 2018
- How long was the total exposure?
- 11.3 hours
- What equipment was used?
- Skywatcher Quattro 200 CF, NEQ6 Pro, Atik 428EX Mono, Skywatcher ST-80, QHY5L-II
- Where was it taken from?
- Lisburn, Northern Ireland.