Polaris (SAO 308): The Great Star That Pivots the Sky

Into the north window of my chamber glows the Pole Star with uncanny light. All through the long hellish hours of blackness it shines there. And in the autumn of the year, when the winds from the north curse and whine, and the red-leaved trees of the swamp mutter things to one another in the small hours of the morning under the horned waning moon, I sit by the casement and watch that star. Down from the heights reels the glittering Cassiopeia as the hours wear on, while Charles’ Wain lumbers up from behind the vapour-soaked swamp trees that sway in the night-wind. Just before dawn Arcturus winks ruddily from above the cemetery on the low hillock, and Coma Berenices shimmers weirdly afar off in the mysterious east; but still the Pole Star leers down from the same place in the black vault, winking hideously like an insane watching eye which strives to convey some strange message, yet recalls nothing save that it once had a message to convey. Sometimes, when it is cloudy, I can sleep.

— H. P. Lovecraft, “Polaris” (1918)

More than a century after the publication of this dramatic and atmospheric story, the North Star is still there — inviting us to photograph it with modern cameras and image-compositing techniques.

Image data was captured from a balcony over four summer nights (August 19, 20, 23, and 25, 2017).

Equipment:

• Pentacon 50mm f/1.8 lens (stopped down to f/2.8)
• ZWO ASI174MM camera with a Baader Planetarium UV/IR cut filter
• Sky-Watcher EQ3-2 mount with a single-axis electric drive
• Nikon D5100 with a Nikon 18–105mm kit lens for capturing star colors

Exposure:

• 280 × 200 s for the L channel (total integration time: 15.5 hours)
• 60 × 30 s for star colors

Software:

• MaximDL (calibration and stacking)
• Astra Image (histogram stretching, deconvolution)
• PixInsight LE (sky gradient removal)
• Adobe Photoshop (post-processing, LRGB combination)

Polaris barely moves, which makes long exposures forgiving and tracking almost effortless. Ironically, that same stillness makes it harder to frame: centering a star that refuses to drift is a small but persistent challenge.