NGC 5907 — Galaxy in Draco

NGC 5907, the Splinter or Knife Edge Galaxy, is one of the thinnest edge-on spirals known, located in Draco about 50 million light-years away. Its slender, almost ruler-straight profile spans more than 12 arcminutes, with a remarkably small bulge and a long disk that fades smoothly into the surrounding space. Deep imaging has revealed an extraordinary feature: a giant, looping stellar stream wrapping around the galaxy several times, a relic of a small companion galaxy that NGC 5907 cannibalized over the past few billion years. At magnitude 10.3, the main disk is a comfortable telescopic target; the stream is purely photographic.

A 4-inch at moderate power shows a long, narrow streak with no obvious central concentration — the bulge is so small that it barely marks the centre of the disk. An 8-inch at 150-200x reveals the thin profile beautifully, with a faint dust lane just visible along the eastern edge from very dark sites. A 12-inch begins to bring out the lane and the very gradual fade-out of the disk's tips. Star-hop from Iota Draconis (Edasich) about 4 degrees south. Best observed April through August.

Discovered by William Herschel on 5 May 1788. The galaxy was relatively obscure until the early 2000s, when a team led by amateur astrophotographer R. Jay GaBany and astronomer David Martínez-Delgado published deep amateur-driven images revealing the giant looping stellar stream — a landmark in showing that minor mergers leave persistent fossil records around even apparently undisturbed galaxies.