Trip to Chile, May 2012

Even in early morning, SMC was lying pretty low above the horizon (10° elevation max.)

Object information

Wikipedia The Small Magellanic Cloud (SMC) is a dwarf galaxy. It has a diameter of about 7,000 light-years and contains several hundred million stars. It has a total mass of approximately 7 billion times the mass of our Sun. Some speculate that the SMC was once a barred spiral galaxy that was disrupted by the Milky Way to become somewhat irregular. It contains a central bar structure.

At a distance of about 200,000 light-years, it is one of the Milky Way's nearest neighbors. It is also one of the most distant objects that can be seen with the naked eye. With a mean declination of approximately -73 degrees, it can only be viewed from the Southern Hemisphere and the lower latitudes of the Northern Hemisphere. It is located in the constellation of Tucana and appears as a hazy, light patch in the night sky about 3 degrees across. It looks like a detached piece of the Milky Way. Since it has a very low surface brightness, it is best viewed from a dark site away from city lights. It forms a pair with the Large Magellanic Cloud (LMC), which lies a further 20 degrees to the east. The Small Magellanic Cloud is a member of the Local Group.

Processing details

[i]Preprocessing using DSS[/i]

Darks and lights added using Sigma clipping method (kappa=2, 5 its)

[i]Processing using PixInsight[/i]

BackgroundNeutr (thr=0.1), DynamicCrop (remove dead border lines)

DynamicBackgroundExtraction : raw image contains a strong linear vertical gradient, since object was reaaly low on the horizon (tol=2, shad relax=4, samples radius=25, samples/row=10 + manual samples)

HistogramTransform

Masks generation : starMask (ATrousWavelets 7 layers, keep 6 first), galaxyMask (ATousWavelets 7 layers, keep only last), lheMask (PixelMath : Min(inv(starMask),galaxyMask))

No HDRMultiscaleWavelets

Star size reduction, using Morphology (starMask active, 55% amount)

LocalHistogramEqualization (lheMask active, radius=70, contrast=2.5)

ACDNR (lightness mask: m=0.46, s=0.12, h=0.57, stdev lum=2, stdev chrom=3)

SCNR (green only)

Saturation boost, using Curves (S channel, 3 steps)

Final histogram correction yith HistogramTransformation (RGB + R blackpoint + G blackpoint)