Lewis Swift discovered NGC 7803 = Sw. VI-98 on 5 Aug 1886 and recorded pF; pS; F * nr np; near and between the 2 preceding of 3 stars in a line; np of 2 [with NGC 7810?]." His position is 12 seconds of RA west and 50" north of UGC 12906 (3' error), the brightest galaxy in HCG 100. Howe measured an accurate position in 1897.

400/500mm - 17.5" (11/10/96): fairly faint, fairly small, elongated nearly 2:1 WSW-ENE, brighter core. A pair of mag 14/15 stars lie 1' WNW. This galaxy is the brightest in the compact HCG 100 group. Forms a close pair with HCG 100B 1.5' E. The fainter companion is very faint, small, round, 0.4' diameter. Sandwiched between NGC 7803 1.5' W and a mag 11 star 46" ENE.

17.5" (9/15/90): faint, small, elongated 3:2 WSW-ENE, almost even surface brightness. A pair of mag 14 and 14.5 stars is 1' WNW. Collinear with two stars mag 12.5 and mag 11 2.3' E and 4.0' E, respectively. NGC 7810 lies 18' ESE.

600/800mm - 24" (11/7/18): at 375x; moderately bright and large, oval ~3:2 E-W, ~45"x30". Contains a relatively large, very bright core region that gradually increases towards the center. A pair of mag 14.5/15 stars lie 1' NW. Forms a close pair with HCG 100B 1.5' E. The companion was faint, fairly small, slightly elongated N-S, 25"x20", low even surface brightness. A mag 12 star lies 45" E. HCG 100C, 2.5' NW, appeared very faint, small, slightly elongated WSW-ENE, 20"x15". Often visible with careful averted vision but could not nearly hold. Mrk 935 (not a HCG 100 member but same redshift) at 6' E of NGC 7803 was almost fairly faint, small, roundish, 20" diameter.

900/1200mm - 48" (10/24/11): at 610x appeared bright, oval 3:2 WSW-ENE, 0.8'x0.5'. Sharply concentrated with a very small, very bright core. A 17" pair of mag 14.4/15.1 stars is 1' NW. Flanked by HCG 100B 1.5' E and 100D 1.2' W. All 4 galaxies in HCG 100 fit within a circle of radius 2'. In addition, MCG +02-01-013, an extremely faint galaxy, lies 1.2' SE of 100D and Mrk 935 lies 4.7' ESE of 100D.

Notes by Steve Gottlieb