The following observational history of M42 = NGC 1976 = h360 is largely from Wolfgang Steinicke and http://seds.org/messier/more/m042_dis.html

The Orion Nebula was probably discovered in November 1610 by Nicholas-Claude Fabri de Peiresc (1580-1637), a French lawyer, who turned his telescope (given to him by Galileo) to Orion and reported a "small illuminated cloud" near the middle star of Orion's Sword. This sighting, however, was not published, but only reported in Peiresc's personal documents and mentioned by Bigourdan in 1916. Jesuit astronomer Johann Baptist Cysat (1588-1657) of Lucerne was independently found it the following year. In 1619 he compared it to a comet he had observed in 1618. Cysat's work also did not get widely circulated but was found and reported by Rudolf Wolf in 1854. So, Dreyer included Cysat under the "Other Observers" column in the NGC. The first known (very rough) sketch of the Orion nebula was created by Sicilian astronomer Giovanni Batista Hodierna before 1654 and included three stars, probably Theta1, Theta2A and Theta2B. As he was little-known, his work was lost and not rediscovered until the 1980's.

None of the early discoveries were known when Christian Huygens rediscovered the nebula in 1656 with a 50mm refractor and published the first printed sketch which appeared in his "Systema Saturnium" in 1659, gaining credit for a long time as the discoverer, as reported by Halley and Messier. Huygens's sketch included 3 stars in the trapezium and the general shape of the bright central part of the nebula. Messier's more detailed sketch [made in 1769] showing the wings and the "fish's mouth" near the trapezium was published in 1771 (M?moires de l'Acad?mie Royale), though soon after William Herschel trained his large mirrors towards M42 (first observations in March 1774) and obtained much more detailed views. He called it "altogether the most wonderful object in the heavens." (16 Oct 1784)

M42 was one of the objects Lord Rosse attempted to "resolve" in 1845 and 1846 using his new 72-inch. After several bouts of poor weather, in February of 1846 he wrote "we are still in doubt as to the resolvability of the Nebula in Orion. The great instrument has shown us an immense number of stars in it, dense groups in the immediate vicinity of the Trapezium, but further evidence is I think wanting." A month later he was more convinced, writing in a letter "...there can be little if any doubt as to the resolvability of the nebulae...we could plainly see that all about the trapezium is a mass of stars; the rest of the nebula also abounding with stars, and exhibiting the characteristics of resolvability strongly marked." Most astronomers accepted these claims, though a few such as Wilhelm Struve challenged the alleged resolution. Clearly the Orion was a poor choice to decide resolvability as there are many stars associated with it, but the Irish observers also claimed resolvability for the Crab Nebula and the Ring Nebula (especially by Romney Robinson). George Bond, son of William Cranch Bond and Director of the Harvard College Observatory, claimed to have confirmed Rosse's resolution using HCO's new 15" refractor. In his first examination on 21-22 Sep 1847, he scrawled in his notebook, "Resolved. Mottled. Abundance of Stars." He reported to Harvard's president that "You will rejoice with me that the great Nebula in Orion has yielded to the powers of our incomparable telescope!"

Ronald Stoyan, in "Sketching the Orion Nebula" (Astronomy, Feb 2013), stated that Bond determined the positions of all stars he could perceive through the 15-inch (HCO refractor) in a 20' radius around the Trapezium. Working through seven winter seasons from 1857 to 1864 and finally reaching a field of 3.36? square, he catalogued 1,101 stars as faint as 15th magnitude, observed numerous various stars, and described M42 in metriculous detail like no one before. But above all, he sketched what he saw at the eyepiece - the first complete and accurate "image" of this region. His eye for detail was so that that the engraver [for the 1867 "Observations upon the Great Nebula in Orion" in http://adsabs.harvard.edu/full/1867AnHar...5D...3B] had to look through the telescope to adequately reproduce Bond's impressions. The result was the most accurate and elaborate astronomical drawing ever done. Bond's cousin, American astronomer Edward S. Holden, said in 1882 that it was the "most satisfactory representation of any celestial object." [A biography of George Bond, as well as his sketch of the Orion Nebula is at http://ejamison.net/bond.html]

The Orion Nebula was reported early on by various observers as possibly variable, with changes in both shape and brightness. Edward Holden gives a comprehensive history of observations of the Orion Nebula by 44 individuals, from Cysat in 1619 to Draper in 1880. See http://openlibrary.org/books/OL7237514M/. Henry Draper took the first photograph of the Orion Nebula on 30 Sep 1880 with an 11-inch Clark refractor, though the resolution and details were very poor. In 1882-83, Ainslee Common obtained a number of impressive long-exposure photographs using his 36-inch silver-on-glass reflector (first to show details not visible naked-eye) and in 1889 Isaac Roberts produced some excellent wide-field photographs of M42 using a 20-inch Grubb reflector.

400/500mm - 17.5" (10/12/85): best emission nebula in northern sky, fantastic view under all conditions, bright colored wings sweep to the east and south. The remarkable structure is difficult to describe but includes bays, filaments, knots, nebulous stars and a huge outer loop. Definite colors are visible including pale greens and pinks. Highlighted by the Trapezium which contains six stars and appears to reside in a darker hollow. The bright portion surrounding Theta probably has the highest surface brightness of any HII region in the sky with an "electric" appearance. Dark streaks and a dark wedge = "fish's mouth" intrudes on the NE side. Using an H-Beta filter, the nebulosity significantly dims in general but there is one outer wing or loop on the west side (oriented N-S) which obviously increases in contrast with the filter!

900/1200mm - 48" (4/1/11): the Trapezium was first object viewed while the sky was still darkening. The "H" star (discovered by Barnard in 1888 with the Lick 36" was easily visible without reference to a chart, though I apparently missed the G star inside the Trapezium and a fainter companion to H at 1.3" separation. The "E" component was seen for the first time with a vivid orange color! In addition, due north of the A-E pair is a faint double star near the edge of the darker central pocket containing the Trapezium. On the opposite side (SE) of the Trapezium (at the edge of the inner pocket) are a wide pair of stars (~20") oriented E-W with possibly a third extremely difficult star between and a bit further east. Although I didn't take notes or try to sketch the main features of M42, there were several faint pink or red stars peppered over the glow of the nebula!

Notes by Steve Gottlieb