Faint, obscured by stars, but Huge!

This is a very faint object swamped by the rich star fields along the border of Auriga and Taurus. Note how large an area this super nova remnant subtends on the night sky in comparison to the full moon, here added digitally for scale! Were only human eyes sensitive to the light of hydrogen alpha emission, we would readily see this knotted skein of fibrous tendrils glowing large in the night sky on moonless nights. As it is, the object is invisible to the eye even in telescopes! It bears the name Simeis147 or Simeiz147 from its entry in a catalogue compiled by the Crimean Astrophysical Observatory, located at Simeis in the Ukraine, at which it was discovered. Despite its huge apparent size on the night sky, it is so faint, and so ensnarled in the rich field of stars surrounding it, that it was discovered on red-sensitive photographic plates only in 1952! It is the expanding remnant of a star which exploded some 40,000 years ago. Its progenitor star, reduced to a pulsar, hides in its core. This sprawling supernova remnant lies some 3,000 light years distant from earth.

HaRGB Mosaic Combination

Data
Taking Camera SBIG STL11002M	Nova Scotia, Winter 2014 ~mag 6.4 @-20C
Imaging OTA	Takahashi FSQ106EDXIII with QE Reducer
Equivalent focal length and ratio	385mm f3.6
Mount	AP1600
Guiding	PHD2/MMOAG/Lodestar X2
HaRGB Combination - Total Integration Time 46hrs	Three Panel Mosaic-Each Panel Ha-25X30min, R4x10min, G-4x10min, B4X10min-Astrodon 5nm Ha and Gen 2 I series RGB Filters. All Binned 1X1
Calibration and Stacking	Darks,Flats and Bias - PixInsight
Reprocessed Feb 2023	PixInsight, Affinity Photo v2.04 and Bob Franke's CCDBand-Aid