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[M 81]

Messier 81

Observations and Descriptions

Discovered by Johann Elert Bode in 1774.
Independently discovered by Johann Gottfried Koehler 1772-1778.
Independently rediscovered by Pierre Méchain in August 1779.

Messier: M81.
February 9, 1781. 81. 9h 37m 51s (144d 27' 44") +70d 07' 24"
Méchain: (144d 27' 00") +70d 04' 00"
"A nebula near the ear of the great Bear [Ursa Major], on the parallel of the star d, of fourth or fifth magnitude: its position was determined from that star. This nebula is a little oval, the center clear, & one can see it well in an ordinary telescope of 3.5 feet [FL]. It was discovered by M. Bode at Berlin on December 31, 1774, & by M. Méchain, in the month August 1779."

Bode: Bode 17.
[with M82] "Two small nebulae 3/4 degrees separated."
"On December 31 [1774], I found through the seven-foot telescope, closely above the head of UMa, east near the star d at its ear, two small nebulous patches separated by about 0.75 degrees, the positions of which relative to the neighbored small stars are shown in the tenth figure. The patch Alpha (M81) appears mostly round and has a dense nucleus in the middle. The other, Beta, on the other hand, is very pale and of elongated shape. I could determine the separation of Alpha to d as 2deg 7', to Rho as 5deg 2' and to 2 Sigma as 4deg 32' with some acuracy; Beta was too faint and disappeared from my eyes as soon as I shifted apart the halves of the objective glass."

Koehler: Koehler No. 8a
[With M82] "Two nebulous stars at the ear of the Great Bear [Ursa Major]."

William Herschel
[SP2 p. 659]
1801, Nov. 8 (Sw. 1100). eB [extremely bright], the bright part confined to a very small place; the nebulosity is of the milky kins, vm. E. npsf. [very much extended north preceding (NW) to south following (SE)].
1802, Sept. 30 (Sw. 1112). vB. eL. [very bright, extremely large]; it very nearly fills all the field, it loses itself imperceptibly, m. E. npsf. [much extended north preceding (NW) to south following (SE)]; I can trace it nearly 1/2 deg in extent beyond the bright part.
1810, Nov. 26, Review. I viewed the nebula with the large 10 feet. It has a bright, resolvable nucleus, certainly coonsisting either of 3 or 4 stars or something resembling them. It is about 15 or 16' long. The object was already too low to be seen to an advantage.

John Herschel (1833): h 649.
h 649 = M82 [actually M81]
Sweep 377 (October 28, 1831)
RA 9h 41m 16.9s, NPD 20d 7' 49" (1830.0) [Right Ascension and North Polar Distance]
eB; eL; E, pos=156 deg; gb and then vsmbM, with faint rays of light nearly to extremities of field (15'). The most condensed part is 4'l and 3' br.
extremely bright; extremely large; elongated, at position angle 156 deg; gradually brighter and then very suddenly much brighter toward the middle, with faint rays of light nearly to extremities of field (15'). The most condensed part is 4' long and 3' broad.

Smyth: CCCLXIX [369]. M81 and M82.
CCCLXIX. 81 M. and 82 M. Ursae Majoris.
AR 9h 42m 10s, Dec N 69d 51'.8
Mean Epoch of Observation: 1837.19 [March 1837]
No. 81 is a fine bright oval nebula, of a white colour, in the Great Bear's ear, which was first registered by M. Messier in 1781, and exhibited a mottled nebulosity to WH [William Herschel]. Its major axis lies np [north preceding, NW] to sf [south following, SE]; and it certainly is brightest in the middle. There are several minute companions [stars] in the field, of which a close double star in the sp [south preceding, SW] quadrant is No. 1386 in Struve#s grand Catalogue, and by him marked vicinae; the members are both of 9th magnitude, and trend np [north preceding, NW] to <7>sf [south following, SE], about 2" apart, forming a fine though difficult object.
With a low power, No. 82 M. can be brought into the north part pf the same field of view, although they are half a degree apart. It is very long, narrow, and bright, especially at its northern limb, but rather paler than No. 81. A line drawn through three stars in the sp [south preceding, SW] to a fourth in the nf [north following, NE] passes directly through the nebula. The two nebulae precede Lambda, in the end of Draco's tail, by 25deg, but as the vicinity is deficient of large [bright] stars, they are not readily fished up.
The apparent place here taken, is that of a small star between the two nebulae, which was differentiated with 29 Ursae Majoris, and every care taken in the reduction. The bright star in the animal's chest, south of 29, viz. Phi, is pronounced to be double, both companions being of the 5th magnitude, and only half a second asunder.

John Herschel, General Catalogue: GC 1949.
GC 1949 = h 649 = M81.
RA 9h 43m 48.9s, NPD 20d 16' 10.0" (1860.0) [Right Ascension and North Polar Distance]
!; eB; eL; E 156deg.0; g,svmbMBN. 4 observations by W. & J. Herschel.
Remarkable; extremely bright; extremely large; extended in position angle 156.0 degrees; gradually, then suddenly very much brighter toward the middle where there is a bright nucleus.

GC 1953.
GC 1953 = W.H. nova? = M81??
RA 9h 44m 38.0s, NPD 20d 12' 18.9" (1860.0)
vB; cL; mE; 5 or 6 st (?) inv. 1 observation by W. Herschel.
Very bright; considerably large; much extended; 5 or 6 stars (?) involved
Remark: GC 1953 M. 81 ?? A nebula observed by W.H. as described, but differing most materially in place from M. 81. It would certainly be very extraordinary should three nebulae so extremely remarkable as M. 81 and 82 and this be found to lie so near together.

[Further Observations on the Spectra of some Nebulae, with a Mode of determining the Brightness of these Bodies. Phil. Trans. Roy. Soc., Vol. 156 (1866), p. 381-397; here p. 388]
[No. [GC] 1949. 649 h. 81 M. R.A. 9h 43m 48s.9. N.P.D. 20d 16' 10". Extremely bright; extremely large; gradually, suddenly very much brighter in the middle.]
Spectrum continuous; the red end of the spectrum wanting or very faint.

Dreyer (1877)
M. Tempel, of the Observatory at Arcetri, near Florence, has made a considerable number of drawings of Nebulae with the two fine Amici telescopes at his disposal, which it is to be hoped may soon be published. The following Nebulae have, for the first time, been carefully drawn ar Arcetri: - GC .., 1949 [M 81], 1950 [M82], 2318 [M108], .., 4315 [M 14], ..

Dreyer: NGC 3031.
NGC 3031 = GC 1949 = GC 1953 = h 649; Bode, M 81.
RA 9h 43m 56s, NPD 20d 16.7' (1860.0) [Right Ascension and North Polar Distance]
! eB, eL, E 156deg , gsvmbMBN; = M81
Remarkable, extremely bright, extremely large, extended in position angle 156 degrees, gradually, then suddenly very much brighter toward the middle where there is a bright nucleus.

[Descriptions of 762 Nebulae ans Clusters photographed with the Crossley Reflector. Publ. Lick Obs., No. 13, Part I, p. 9-42]
NGC 3031, RA= 9:47.3, Dec=+69:32. [Publ. Lick Obs.] Vol. VIII, Plate 21; M. 81. This very beautiful spiral is about 16'x10', and is too well known to require description. Short exposures show that the nucleus is almost stellar. Central part very bright. See Abs. Eff. 10 s.n.
  • Observing Reports for M81 (IAAC Netastrocatalog)

    Hartmut Frommert
    Christine Kronberg

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    Last Modification: October 21, 2005