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NGC 2070
Tarantula
Bennett 35,
ESO057-EN006
RA 05:38:37
Dec
-69° 05.7'
Bright nebula |
This nebula was discovered by Lacaille and
included in his 1755 catalogue as Class I No. 2. In his half-an-inch 8x
telescope he saw it as being "like the former [NGC 104: "like the
nucleus of a fairly bright comet] but faint."
Dunlop 142: "a pretty large ill-defined
nebula, of an irregular branched figure, with a pretty bright small star in the
south side of the centre, which gives it the appearance of a nucleus. This is
resolvable into very minute stars - Figure 4. is a very good representation of
the nebula resolved. (N.B. The 30 Doradus is surrounded by a number of nebulae
of considerable magnitudes, nine or ten in number, with the 30 Doradus in the
centre.)"
Observed by Sir John Herschel at the Cape of
Good Hope with an 18-inch f/13 speculum telescope. His wrote after his first
observation that it was "an assemblage of loops." He discussed the
object at length: "This is one of the most singular and extraordinary
objects which the heavens present, and derives no small addition to its
intrinsic interest from its situation, which is among the thickest of the
nebulae and clustering groups of the greater Nubecula, of whose total area it
occupies one-five hundredth part. For these reasons, as well as because its real
nature has been completely misunderstood, and its magnified appearance so
strangely misrepresented in the only figure which I am aware to have been made
of it as to convey an entirely erroneous impression both of its form and
structure; I have taken great pains to give as nearly as possible a perfect
representation of it as it appeared in the twenty-feet reflector on a great many
occasions, but more especially on the 29th November, 1834, when a 'very careful
drawing' was made of it by the eye alone, unaided by any micrometrical measures;
and on the 21st and 22nd December, 1835, when the nebula was worked in from the
telescope on a 'skeleton' previously prepared by an approximate reduction of the
micrometrical measures of its principle stars, forming a chart, with a system of
triangles, for its reception and for that of minute stars not susceptible of
micrometric measurement, or not considered as of sufficient importance to be so
measured. This is the only mode in which correct monographs can be executed of
nebulae of this kind which consist of complicated windings and ill-defined
members obliterated by the smallest illumination of the field of view; and in
which the small stars, when very numerous, can be mapped down with tolerable
precision. The following catalogue contains all the stars which I have been able
distinctly to perceive within the area occupied by the nebula and nearly
adjacent to it... [The catalogue contains 105 stars.] The stars thus scattered
over the area occupied by this nebula may or may not be systematically connected
with it, either as an individual object, or as part of the vast and complex
system which constitutes the Nubecula. In respect of their arrangement there is
nothing to distinguish them from those which occupy the rest of the area covered
by the Nubecula, in which every variety of condensation and mode of distribution
is to be met with. The nebula itself (as seen in the 20-feet reflector) is of
the milky or irresolvable kind - quite as free from any mottling or incipient
stellar appearance as any other nebula which I can remember to have examined
with that instrument. Its situation in the Nubecula is immediately adjacent to
two large and rich clusters [NGC 2042 and NGC 2055]. Mr Dunlop remarks that 'The
30 Doradus is surrounded by a number of nebulae of considerable magnitudes, nine
or ten in number, with the 30 Doradus in the centre.', of which nebulae he gives
a figured representation. For what objects these can be intended I am quite at a
loss to conjecture, unless they be the brighter portions of the nebulous
convolutions seen without their connecting enbranchments. But with this
supposition their relative situations, intensities, and magnitudes in the figure
alluded to, so far as I am able to judge, appear irreconcilable."
Simon Tsang notes that it "appeared
well-resolved in a 13-inch reflector at 120x, with extensions going in six
directions, some looping like an insect's legs. What eerie charm!"
The nebula and cluster lie within the LMC
O-association No. 100; the brightest star in the cluster is 11.7 mag. (Hodge,
P.W. and Lucke, P.B., Astronomical Journal, Vol 75, No. 8, 1970, p933-937).
Henize (Catalogues of Hydrogen Alpha Emission Stars and Nebulae in the
Magellanic Clouds, Astrophysical Journal Supplement 2, 1956, p315) notes that
his nebula LH N 120-157A is NGC 2070, which is equivalent to HD 38268 Pd.
Henize's nebula includes NGC 2069. He describes 157A as measuring 15.4' x 17.7'
(east-west by north-south), round with a considerably irregular outline and
showing marked structural detail. Shapley and Lindsay ("A Catalogue of
Clusters in the Large Magellanic Cloud", Irish Astronomical Journal, Vol.
6, 1963) give the dimensions as 5.7' x 4.5' and remark "bright scattered
stars in Tarantula nebula." Van den Bergh and Hagen ("UBV photometry
of star clusters in the Magellanic Clouds", Astronomical Journal, Vol. 73,
1968) find that the integrated V magnitude through a 60'' diaphragm is 8.27.
They remark: "This is the 30 Doradus cluster which is located in a 'hole'
in the emission nebula Henize N 157A. The central star of this cluster was
observed on two nights though a 15'' diaphragm yielding V=9.42 ... "
11x80: Large, bright patch
in the LMC, round or slightly elongated. (suburban skies) [AS]
10-inch f/5 Newtonian: This
is definitely the most splendid of all the nebulae in the night sky. Viewing
with a 10-inch f/5 reflector at 30x, the most striking impression is of the
convoluted, textured loops of nebulous light which grow and change appearance as
your attention wanders through the field of view. The brightest part of the
nebulosity is roughly triangular in shape, and radiating outward from this are
many large, elegant arms of gas, liberally scattered with stars. In the southern
part of this brighter triangle lies the brightest star, a 10th mag primary. The
other cluster members show as bright knots within the nebulosity. (suburban
skies) [AS]
13.1-inch f/4.4 Newtonian:
"Special! A familiar object around this time of year. The bright glow of
Buenos Aires (in the southern direction of Martinez) does not hide the principal
portions of this wonderful nebula. The cluster is detached from the background
but with slight concentration; there is a fairly central star. The nebula
totally covers the cluster and extends beyond it in a bright arc to the east,
and a fainter one to the south-west." [229x, 14', sketched] (urban) [GG] |
