Lewis Swift discovered NGC 100 = Sw. III-1 on 10 Nov 1885 with a 16" refractor at his Warner Observatory. His description reads "vF; pS; vE" and the position matches UGC 231 = PGC 1525, the flattest galaxy in the NGC. Guillaume Bigourdan observed the galaxy on 7 Sep 1891 and mentioned its "form and extension are incredible."

400/500mm - 17.5" (10/8/88): very faint, thin edge-on 7:1 WSW-ENE, moderately large, 2.0'x0.3', weak concentration. NGC 99 lies 42' S.

900/1200mm - 48" (11/8/15): bright, extremely large and thin edge-on 10:1 WSW-ENE, extends at least 4.0'x0.4'. A brighter central region extends ~2' in length and the outer extensions fade significantly and taper towards the tips as they dim out. A mag 15.3 star is just beyond the east end of the galaxy. Four mag 15.2-16.2 stars (in an E-W string) lie within 2.5' south of the galaxy.

PGC 1509358 is just south of the southwestern tip of the galaxy. At 488x it appeared very faint (V = 17.2), very small, slightly elongated, ~10"x7". With careful averted vision, I could just hold the galaxy continuously. A fairly difficult mag 17+ star is 30" SW. The redshift based light-travel time (based on z = .10) is 1.2 billion years.

Notes by Steve Gottlieb