Messier 42 - NGC 1976

No dss image available for Messier 42
Aladin viewer for the region around Messier 42
Great Nebula of Orion, Orion Nebula, Ori Nebula, Fish's Head
Bode 10, h 360, GC 1179, 3C 145, LBN 209.13-19.35, LBN 974

Type  Bright Nebula
Magnitude  4
Size  90' x 66'
Right Ascension  5h 35' 17"  (2000)
Declination  5° 23' 28" S
Constellation  Orion
Description  !!!, Theta Orionis and the great nebula M42
Classification  E+R
Observing Notes

Andrew Cooper
Feb 6, 2018    Waikoloa, HI (map)
20cm f/6 Newtonian, Cave Astrola @ 127x
Seeing: 7 Transparency: 7 Moon: 0%

Bright and beautiful!! first light for the newly restored 8" Astrola! The nebula complex fills the field, as the center is the Trapezium, four stars in a tight box, this is at the southern end of a dark void in the nebula, from the center two large sweeps of gas extend east and west over 25', the northern margin is quite abrupt while the southern margin fades gradually into the background, just to the north is a round body of gas (M43) about 10' in diameter surrounding the single 6.8 magnitude star NU Ori, the rift between M42 and M43 is quite dark, NGC1977 The Running Man Nebula is visible further north, the cluster NGC1980 visible to the south

Andrew Cooper
Feb 14, 2016    Waikoloa, HI (map)
20cm f/10 SCT, Celestron C8 @ 57x
Seeing: 6 Transparency: 5 Moon: 25%

Large, bright, beautiful even with a first quarter Moon at zenith just 30° away. trapezium sharp, quite a bit of structure visible along the northern edge

Andrew Cooper
Sep 14, 2015    Hale Pohaku, HI (map)
15cm f/5 Newtonian, Makaʻiki @ 19x
Seeing: 8 Transparency: 6 Moon: 0%

Beautiful! A 40mm eyepiece in the RFT allows the whole complex to be seen from NGC1980 to NGC1981. The main nebula is bright with sweeps of gas spreading to either side of ΘOri, with averted vision the loop is almost closed to the south
Commisioning a new 'scope, Makaʻiki, first light on M42, Bob Goff often declared his desire to visit this nebula in sprit after his death, here and now under a dark sky and beside a hand-made telescope I remember

Andrew Cooper
Nov 17, 2009    Hale Pohaku, HI (map)
46cm f/4.5 Newtonian, Deep Violet @ 95x
Seeing: 7 Transparency: 7 Moon: 0%

Absolutely sublime under a dark sky and with the big 'scope, a great deal of detail to be seen, the northern edges are well defined great sweeps of gas, the central core around the trapezium is notably mottled, six stars easily made out in the central cavity, the entire structure is vividly green in color, just a hint of salmon on the northern edge

Andrew Cooper
Oct 22, 2006    TIMPA, Avra Valley, AZ (map)
12x36 Canon Image Stabilized Binoculars

Beautiful! large! bright! extensive nebula over a degree across, several involved stars, trapezium not split, the entire region from NGC1981 to Iota Ori fills the field with beauty

Andrew Cooper
Jan 12, 2002    Las Cienegas, Sonoita, AZ (map)
46cm f/4.5 Deep Violet

Very large, bright, clearly green with a hint of red around the margins. a squarish bright region around the trapezium with the 'wings' spreading east-west from there, the eastern loop is visible for 180 degrees around to the south of the main core

Rev. T.W. Webb
May 19, 1885    Hardwick, Herefordshire, England (map)

The Great Nebula, one of the most wonderful objects in the heavens; readily visible to the naked eye, yet strangely missed, as Humbolt says, by Galileo, who paid great attention to Orion.

Telescope shows an irregular branching mass or greenish haze, in some directions moderately well defined where the dark sky penetrates it in deep openings: in others melting imperceptibly away over such an extent that Se., by moving his telescope rapidly to gain full contrast, has traced it in singular convolutions, and with a considerable break near σ through 5½° of Decl., and 4° of R.A. —from ζ to 49, and probably H. V 38 -a prodigious diffusion.

Bond II also found it encompassed by a distant nebulous loop; and in various parts detected about 20 curved wreaths, indicating somewhat of a spiral structure, Its real nature was long a profound mystery. It resisted H.'s 40-ft. refl., in which it was one of the first objects viewed, and, together with the Andromeda, suggested to him the widely discussed Nebula Hypothesis, which would see here an unformed fiery mist, the chaotic material of future suns. h. found but the aspect of 'a curdling liquid, or a surface strewed over with flocks of wool, or the breaking up of a mackerel sky.'

The E. of Rosse, with his 3-ft. refl., La., with his 2-ft. spec. in the Maltese sky, could advance no further; it was long believed that the 6-ft. mirror of the E. of Rosse had lifted the veil, and distinguished in some places its starry composition; Bond, too, arrived at the same conclusion; and Se. with smaller, but very perfect means, though he could detect the glittering 'star dust.'

Yet, though this would imply a permanent form, there were some strange discrepancies in the drawings of the best hands. h., in England, the same observer at the Cape of Good Hope, Bond, La., Liapounov with a 9-½in. achr. at Kazan. OΣ, at Poulkova, all differ in various ways; the latter even believed that the brightness of the central part was in a state of continual variation; and the subsequently published labors or Rosse, La., and Se., are far from correspondent in detail. All this is strange; and the spectrum analysis of Huggins has only added to the wonder by exhibiting it as a mass of incandescent gasses.

In the densest part, four stars, 6, 7, 7.5, 8 mg., form a trapezium known as Theta Orionis. Sm. gives their colors pale w., faint lilac, garnet, reddish. OΣ thinks that several involved stars are subject to change, and remarks that 'the existence of so many variable stars on such a small space in the central part of the most curious nebula in the heavens must of course induce us to suppose these phenomena intimately connect with the mysterious nature of that body.' (abridged)
― Celestial Objects for Common Telescopes, T. W. Webb, 1917

Captain William Henry Smyth
Jan 26, 1834    No. 6 The Crescent, Bedford, England (map)
150mm f/17.6 refractor by Tully 1827

[From entry CCXVI for θ1 Ori...] Ptolemy, Tycho Brahé, and Hevelius, ranked θ of the 3rd magnitude, as did Bayer in his Uranometria, all evidently supposing the two contiguous stars and the bright spot constituted a single star. The effulgent nebula in which it is placed, familiarly called the Fish's head, with its streaming appendages, certainly has an irregular resemblance to the head of some monster of the polyneme genus.

Its brilliancy is not equal throughout, but the glare of the brighter parts gives intensity to the darkness which they bound, and excites a sensation of looking through it into the luminous regions of illimitable space, a sensation not entirely owing to any optical illusion of contrast. This supposition must have forced itself upon Huygens, independently of any recollection of the empyrean heaven of the ancients; and had Voltaire seen the object under powerful means, he would hardly have lashed Dr. Derham for asking, whether nebube be not this shining region, seen through a chasm of the primum mobile. Another wonderful singularity is, that the nebulous and apparently attenuated matter seems to recede from the stars of the trapezium, so as to leave a black space around each, between them and the glow, as though they were either repelling or absorbing it.

This is a most splendid object under any telescope, but the greater the optical power applied, the more inexplicable does it become. My own telescope showed it to very great advantage, but it is here where the light-grasping quality of reflectors is brought advantageously to bear. Thus in the twenty-foot telescope at Slough, Sir John Herschel gained perceptions of its modification which were not decided to my view: "I know not," he says, "how to describe it better than by comparing it to a curdling liquid, or a surface strewed over with flocks of wool, or to the breaking up of a mackerel sky, when the clouds of which it consists begin to assume a cirrous appearance. It is not very unlike the mottling of the sun's disc, only, if I may so express myself, the grain is much coarser, and the intervals darker; and the flocculi, instead of being generally round, are drawn into little wisps. They present, however, no appearance of being composed of stars, and their aspect is altogether different from that of resolvable nebulas." Such, at present, are the only ascertained peculiarities of the wondrous mass.

It is pronounced to be of the singular nature termed milky nebulosity by Sir William Herschel: "to attempt," he remarks, "even at a guess at what this light may be, would be presumptuous. If it should be surmised, for instance, that this nebulosity is of the nature of the zodiacal light, we should then be obliged to admit the existence of an effect without its cause. An idea of a phosphorical condition is not more philosophical, unless we could show from what source of phosphorical matter such immeasurable tracts of luminous phenomena could draw their existence, and permanency: for though minute changes have been observed, yet a general resemblance, allowing for the difference of telescopes, is still to be perceived in the great nebulosity of Orion, ever since the time of its first discovery." This illustrious astronomer was, at first, inclined to consider all the nebulae as resolvable, but this milky instance, with that in Andromeda, contradicted the notion, and led him to inferences respecting nebulous matter, and its possible gradation to stars by condensation, so as to form a distinct and plausible theory of cosmogony; with the originality of which neither the A'kásah., fifth element of the Brahmans, of which the heavens are formed, nor the vague notions of Tycho Brahé and Kepler, can properly be said to interfere. From these bold and almost overwhelming ideas we may yet become conscious, as well of the operations of the powerful agents by which whole systems are formed, as of those tremendous forces by which others are destroyed.

We are told that this nebula was one of the first fruits of Galileo's telescope; but it is certain that Huygens discovered it by accident in 1656, as stated in his Systema Saturnium. where he notes, "Portentum, cui certe simile aliud nusquàm apud reliquas fixas potuit animadverti." From a comparison of the descriptions and drawings of this object, since his time, great alterations might be inferred; but astronomical delineation was not then sufficiently advanced to render the diagrams at all satisfactory, nor were the instruments sufficiently powerful. Thus, while one man thinks his 3½ foot telescope indicated "myriads upon myriads " of stars in its composition, Lord Rosse, with the most powerful and perfect instrument extant, gained no appearance of re-solution. It may therefore be concluded, that the first rigidly accurate representation of it, is that by Sir John Herschel; and he who wishes to acquire all the actual knowledge we at present possess on the subject, cannot refer to a better description than that contained in his paper, published in the second volume of the Memoirs of the Astronomical Society. "Several astronomers," says Sir John, "on comparing this nebula with the figures of it handed down to us by its discoverer, Huygens, have concluded that its form has undergone a perceptible change; but when it is considered how difficult it is to represent such an object duly, and how entirely its appearance will differ even in the same telescope, according to the clearness of the air, or other temporary causes, we shall readily admit that we have no evidence of change that can be relied on." To the drawing which illustrates that account, posterity will refer with confidence, in order to "catch Nature in the fact:" meantime, it seems clear, that if the parallax of this nebula be no greater than that of the stars, as one hypothesis assumes, its breadth cannot be less than a hundred times that of the diameter of the Earth's orbit: but if, as is still more probable, at a vast distance beyond, its magnitude must be utterly inconceivable.

This luminous spot is so well known to all star-gazers, that it is hardly necessary to add, that a line projected from α Orionis, through ζ, the third of the belt, will pass upon θ and the nebula, in the sword-scabbard. The portion called the Fish's mouth, with the well-known trapezium, may be rudely sketched as in the preceding figure*.
― A Cycle of Celestial Objects Vol II, The Bedford Catalogue, William Henry Smyth, 1844

Johann Elert Bode
Sep 22, 1775    Berlin Observatory, Germany (map)

The location of the remarkable nebulous region at the sword of Orion is given very indefinite in most of the sky charts and astronomical scripts known to us. But the 15th figure depicts its actual location correctly. The star Theta, which is the one in the middleat the sword, and was described as double by Flamsteed, is situated in the middle of this nebula. 1. Theta appears fourfold in good telescopes, as it has 3 small stars close to it to the east; 2. Theta is close to the east near the previous one and has two small stars east and near it. These indicated seven stars are all involved ina vivid nebula or luminous glow, which appears inclined from evening to morning, in an elongated and curved tongue-shaped figure. Close to the north of this nebula, a small star appears which has something nebulous around it [M43]. About 32' north of 1 and 2 Theta are the stars 1 and 2 c Ori; and about equally south of them is the star Iota after Flamsteed.

Charles Messier
Jan 4, 1769    

Position of the beautiful nebula in the sword of Orion, around the star Theta which contains with three other smaller stars which one cannot see but with good instruments. Messier has entered into treat details in this great nebula; he has created a drawing, made with the greatest care, which one can see in the Memoirs of the Academy for 1771, plate VIII. It was Huygens who discovered it in 1656: it has been observed since by many astronomers. Reported in the English Atlas.
― Connaissance des Temps, 1781
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Messier 42