Re-processed 12th August 2017 using the new PhotometricColorCalibration tool from Pixinsight.
This function seeks to adjust the colour balance of the image by plate solving the image and comparing the colour of the stars in the image with the colour values for these stars as stored in various databases.
( please click / tap on image to see larger / sharper )
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Trifid Nebula ( M20, NGC 6514 )
I manged to capture another 60 odd 240sec images in late July to add to the data I captured at the end of June ( Trifid Nebula WIP )
Trifid Nebula in Sagittarius ( Messier 20, NGC 6514 )
( please click / tap on image to see larger and sharper )'
and a crop of the main part of the nebula ...
I am quite pleased with how the colour balance turned out - especially the colours of the stars ( my goal has been to get the colours of the stars as close as I can to how they would look with "daylight" whitebalance and no light pollution / sky glow).
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"High Dynamic Range" ( HDR ) image of the Trifid Nebula - built from exposures ranging from 1/8 to 240 seconds in duration.
Image details:
from nova.astrometry.net:
Size: 52.2 x 35.5 arcmins.
Centre: 18h 2 min 30.8 sec, -22deg 57' 37.7''.
Orientation: up is -88.2 East of North ( ie. E^ N> ).
Telescope:
Orion Optics CT12 Newtonian ( mirror 300mm, fl 1200mm, f4 ).
Corrector: ASA 2" Coma Corrector Quattro 1.175x.
Effective Focal Length / Aperture : 1410mm f4.7.
Mount:
Skywatcher AZ Eq6 GT.
Guiding:
TSOAG9 Off-Axis-Guider, Starlight Xpress Lodestar X2, PHD2 .
Camera:
Nikon D5300 (unmodified) (sensor 23.5 x 15.6mm, 6016x4016 3.9um pixels).
Location:
Blue Mountains, Australia
Moderate light pollution ( pale green zone on darksitefinder.com map ).
Capture:
12 sets of sub-images with exposure duration for each set doubling ( 1/8s to 240s ) all at ISO800.
Processing:
Calibration: master bias, master flat and no darks.
Integration in 12 sets.
105 x 240sec main image.
5 each for exposures 1/8 to 120sec - to caputure highlights.
HDR combination using Pixinsight's PixelMath function.