Messier 87

Possibly discovered by Johann Gottfried Koehler on May 5, 1779.
Discovered independently by Charles Messier on March 18, 1781.

Messier: M87.

March 18, 1781. 87. 12h 19m 48s (184d 57' 06") +13d 38' 01"
"Nebula without star, in Virgo, below & very near a star of eighth magnitude, the star having the same Right Ascension as the nebula, & its Declination was 13d 42' 21" north. This nebula appears at the same luminosity as the two nebulae Nos. 84 and 86."

Koehler:

[Mr. Koehler has discovered], on May 5, again three other somewhat nebulous stars in the area of the northern shoulder of Virgo, at quite a distance of each other.
[Wolfgang Steinicke speculates these may be M84, M86, and M87]

William Herschel

[Unpublished Observations of Messier's Nebulae and Clusters. Scientific Papers, Vol. 2, p. 660]
1784, Apr. 12 (SW. 189). Two S.F. [small, faint) and one L.B. (large, bright) nebula, the two first like the p. [preceding, Western] two [i.e. II.121, 122 (NGCs 4485 and 4461)], the B. [bright] one R. mbM. [round, much brighter to the middle].
1784, Apr. 17 (SW. 199). Three nebulae, the two first vF. S. [very faint, small], the third L. B. mbM. [large, brighte, much brighter to the middle], but diminishing very gradually in brightness. The two first are II.123, 124 [NGCs 4476, 4478].

John Herschel (1833): h 1301.

h 1301 = M87.
Sweep 22 (March 13, 1826)
RA 12h 22m 8.7s, NPD 76d 40' 9" (1830.0). [Right Ascension and North Polar Distance]
vB; R; 60". (Mistaken for II.124)
Very bright; round; 60" [diameter].

Sweep 191 (May 2, 1829)
RA 12h 22m 12.3s, NPD 76d 41' 35" (1830.0).
vB; vL; R
Very bright; very large; round.

Sweep 192 (May 4, 1829)
RA 12h 22m 12.7s, NPD 76d 40' 4" (1830.0).
pB; L; R
Pretty bright; large; round.

Sweep 245 (March 23, 1830)
RA 12h 22m 17.7s, NPD 76d 40' 58" (1830.0).
vB; vL; R; psmbM; r; 3' diam.
Very bright; very large; round; pretty suddenly much brighter toward the middle; mottled; 3' diameter.

Sweep 19 (March 10, 1826)
RA 12h 22m 17.7s, NPD 76d 41' 34" (1830.0).
vB; R; bM. (Taken past merid; PD too great)
Very bright; round; brighter toward the middle. (Taken past meridian [transit]; [N]PD too great)

Smyth

[from the description of M88]
[has it in a chart]
.. "in the immediate nebulous neighborhood" of 88 Messier ..

John Herschel, General Catalogue: GC 3035.

GC 3035 = h 1301 = M87.
RA 12h 23m 44.0s, NPD 76d 50' 39.2" (1860.0). [Right Ascension and North Polar Distance]
vB; vL; R; mbM. 7 observations by W. & J. Herschel.
Very bright; very large; round; much brighter toward the middle.

Dreyer: NGC 4486.

NGC 4486 = GC 3035 = h 1301; M 87.
RA 12h 23m 44s, NPD 76d 50.1' (1860.0). [Right Ascension and North Polar Distance]
vB, vL, R, mbM, 3rd of 3; = M87
Very bright, very large, round, much brighter toward the middle, 3rd of 3 [easternmost].

Curtis

[Descriptions of 762 Nebulae and Clusters photographed with the Crossley Reflector. Publ. Lick Obs., No. 13, Part I, p. 9-42]
NGC 4486, RA=12:25.8, Dec=+12:57. Exceedingly bright; the sharp nucleus shows well in 5m exposure. The brighter central portion is about 0.5' in diameter, and the total diameter is about 2'; nearly round. No spiral structure is discernible. A curious straight ray lies in a gap in the nebulosity in p.a. 20deg, apparently connected with the nucleus by a thin line of matter. The ray is brightest at its inner end, which is 11" from the nucleus. 20 s.n.