William Herschel discovered NGC 5898 = H III-138 = h3597, along with NGC 5903, on 21 May 1784 (sweep 222) and recorded both as "Two, vF, R nebula, not vS, about 7' distance from each other and nearly in the same parallel." John Herschel made a single observation, reporting "pB; R; pgbM; 15"." Vincenzo Cerulli measured an accurate micrometric position in 1895 (given in the IC2 Notes) at his private Italian observatory while searching unsuccessfuly for Comet 1889 V (Brooks).

200/250mm - 8" (7/5/83): faint, small, round.

300/350mm - 13.1" (7/5/83): moderately bright, small, round, gradually increases to a small bright nucleus. Forms a close pair with similar NGC 5903 5.5' ENE.

400/500mm - 18" (6/22/09): moderately bright, moderately large, irregularly round, 1.1'x1.0', sharply concentrated with a small, very bright core. First in a trio with NGC 5903 5.5' ENE and ESO 514-003 5.3' ESE.

18" (6/17/04): moderately bright, moderately large, 1.2'x1.0', sharply concentrated with an intense 20" core. Forms a similar close pair with NGC 5903 5.5' ENE.

Notes by Steve Gottlieb