William Herschel discovered NGC 5557 = H I-99 = h1776 on 1 May 1785 (sweep 405) and recorded "cB, S, R, bM." On 16 May 1787 he logged "vB, S, R, vsmbM." JH made two observations and recorded on sweep 28 "B; R: vsmbM to a *; vF at the borders." He published a sketch in his 1811 paper (Fig. 25) as an illlustration of "nebulae that are suddenly much brighter in the middle."

A total of 11 observations were made at Birr Castle. On 26 Apr 1848, Lord Rosse, or assistant William Rambaut, logged "Nucleus manifested a decidedly spiral arrangement; the neb becomes eF towards the edges; from the upper [sff] par of the nucleus proceeds a circular spiral, only seen by glimpses (as also spirality of nucleus)." The observation was made during the period when spiral structure was sometimes overzealously described. NGC 5557 was included in the list of "Spiral or curvilinear" in LdR's 1850 PT paper, though it is a standard E-type galaxy and the 1861 publication mentions "frequently observed, nothing certain”.

200/250mm - 8" (4/24/82): fairly faint, bright core.

400/500mm - 17.5" (3/23/85): bright, fairly small, small bright core dominates. A very faint star is involved at SE side. The NGC 5544/NGC 5545 pair lies 16' NW and the thin edge-on NGC 5529 is 38' WSW.

Notes by Steve Gottlieb