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Diamonds on black velvet


Hughsie

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Moving on from galaxies for a bit, I decided to explore the world of Globular Clusters and in particular Messier 3.

Messier 3 is situated in the constellation Canes Venatici and as it is above 40 degrees above the horizon and rising, it made a good target over three relatively moonless nights from my back garden.

Situated some 33,900 light years away, M3 is estimated to be 11 billion years old. Having decided to image M3 I really wanted to avoid a ‘crunchy’ image that sometimes occurs with globular clusters as well as show it in a warmer light rather than stark whites and blues. Hopefully you feel I have gone some way to achieving this.

For those interested in the techy bit, read on.....

Equipment used
WilliamOptics Z103 refractor
ZWO ASI 1600mm Pro Cool camera
SkyWatcher EQ6R- Pro mount
Sesto Senso motor focuser
William Optics Flat 6AII reducer/flattener
Chroma LRGB 1.25” filters

Data captured
Luminance 182 x 1 minute
Luminance 31 x 5 minutes
Red 31 x 2 minutes (Bin 2x2)
Green 34 x 2 minutes (Bin 2x2)
Blue 39 x 2 minutes (Bin 2x2)
Total Integration Time 9.2 hours

Dark Frames x 50
Dark Flats x 50
Flat Frames x 50

Software used
PHD2 for guiding
Sequence Generator Pro for image acquisition
PixInsight for processing the image

Processing Workflow post calibration of images
Luminance 1 minute and 5 minute data
Combine 1 minute and 5 minute data sets using HDRComposition to provide contrast and not over expose the core of M3.
Noise reduction using MultiLinearTransformation
Stretch data to produce a permanent image using MaskedStretch so as not to over expose the core.
Lighten image using Curves

Red, Green & Blue Channels (RGB)
Combine R, G & B data sets to produce a single colour image using ChannelCombination
Neutralise image to produce a flat background using BackgroundNeutralisation
Balance the colour using ColourCalibration
Reduce background noise using MultiLinearTransformation.
Small stretch to the image using HistogramTransformation
MaskedStretch to improve lightness without over exposing core.
Increase colour saturation using Curves
Calibrate colour again using ColourCalibration to produce a ‘warmer’ image.
Combine Luminance with RGB using LRGBCombination
Further noise reduction using TGVDenoise
Tweaks of colour/brightness using Curves and appropriate masks.
Subtle sharpening of image using UnsharpMask
..... and a beer or three!

I hope you enjoy my rendition of M3 and feel free to share your thoughts and feedback.

John

M3_LRGB_Border.png

M3_Platesolve.jpg

Edited by Hughsie
Uploaded larger file images
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