Messier 33 - NGC 598

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Triangulum Galaxy
H V 17, h 131, GC 352, MCG +05-04-069, UGC 1117, PGC 5818

Type  Galaxy
Magnitude  5.7
Size  70.8' x 41.7' @ 23°
Right Ascension  1h 33' 50.9"  (2000)
Declination  30° 39' 37" N
Constellation  Triangulum
Description  eB, eL, R, vgbMN
Classification  SA(s)cd
Observing Notes

Andrew Cooper
Nov 23, 2019    Kaʻohe, Mauna Kea, HI (map)
8x42mm Nikon Prostaff 3S Binoculars @ 8x
Seeing: 6 Transparency: 7 Moon: 0%

Large, bright, a misshapen clump of glow about 1° in extent, modestly brighter to the center, easily found off the tip of Triangulum

Andrew Cooper
Aug 21, 2017    Grants Spring, OR (map)
76mm f/6 APO, TeleVue-76 @ 30x
Seeing: 7 Transparency: 7 Moon: 0%

Large, round, about 20' across, gradually brighter to the center fading smoothly into the background at the margins, easily found sweeping north from αTri

Andrew Cooper
Oct 21, 2006    TIMPA, Avra Valley, AZ (map)
12x36 Canon Image Stabilized Binoculars

Large, an oblong hazy patch with no obvious core, just slightly brighter to the center, about 1° across

Andrew Cooper
Oct 24, 2003    Farnsworth Ranch, Pima Co., AZ (map)
46cm f/4.5 Deep Violet

Fantastic! A large diffuse object with a large core, some structure visible at 60x with averted vision, at 175x much of the structure is obvious, particularly the main arms extending north-south from the core and several HII regions with separate designations NGC588, NGC592, NGC595, NGC604, as well as IC137 and IC143, on the whole a sublime and complex scene, a whole new galaxy with the 18

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

Very large, faint, ill defined, visible from its great size (h., nearly ½° n and s, in finder). A very curious object, only fit for low powers, being actually imperceptible, from want of contrast, with my 144. E.of Rosse, who saw it full of knots, found spiral arrangement; two similar curves like an S cross in the centre. Ritchey, who photographed it with the 24-in. at the Yerkes Observatory, with 4 hours' exposure, notes the central parts appear decidedly nebulous, the outer parts parts consist of very faint nebulosity, and numerous curved streams, or wisps of nebulous stars; hundreds of the star-like condensations are shown in the original negative. Closely nf is H. III 150 [NGC604], a small, bright, round neb. with gaseous spect.
― Celestial Objects for Common Telescopes, T. W. Webb, 1917

Captain William Henry Smyth
Sep 28, 1838    No. 6 The Crescent, Bedford, England (map)
150mm f/17.6 refractor by Tully 1827

A large and distinct, but faint pale white nebula, in the precincts of Triangulum, between it and the head of the Northern Fish; with a bright star a little np, and five others following at a distance, between which and the object, there is an indistinct gleam of mere nebulous matter. It was discovered by Messier in 1764; and to William Herschel had a mottled aspect under his seven-foot reflector, in 1783: but afterwards applying a larger telescope, he resolved it into stars— "the smallest points imaginable." By a method of turning the space-penetrating power of his instrument into a gradually increasing series of gauging powers, he considered the profundity of this cluster must be of the 344th order: i.e., 344 times the distance of Sirius from the earth. It is No. 131 of H.'s Catalogue of 1833; and the above place is obtained by differentiation from a Trianguli, from which it is about 4°, and just north of a line run from that star to S Andromedæ.

[It is possible to pick out individual stars in M31 or M33 in modest instruments visually. A number of amateur observers have done so in modern 15-24" telescopes. See Resolving Andromeda, Bob King, Sky & Telescope, October 5, 2016.

Sirius is 8.6 light years distant, 8.6 x 344 = 2958ly for Herschel's estimate, slightly less than the actual distance of 2.72 million light years]
― A Cycle of Celestial Objects Vol II, The Bedford Catalogue, William Henry Smyth, 1844

John Herschel
Sep 15, 1828    

Enormously large; very gradually brighter toward the middle. The nucleus taken; has a star of 12 m, north following of the nucleus. The diffused nebula extends 15' south and as much nearly to the north. It has irregularities of light, and even feeble subordinate nuclei and many small stars. Probably H V.17 is part of the diffuse nebula of M33.

Charles Messier
Aug 25, 1764    

Nebula discovered between the head of the Northern Fish & the great Triangle, a bit distant from a star of 6th magnitude: The nebula is of a whitish light of almost even density, however a little brighter along two-third of its diameter, & contains no star. One sees it with difficulty with an ordinary telescope of 1-foot. Its position was determined from α Trianguli. Seen again September 27, 1780.
― Connaissance des Temps, 1781
Other Data Sources for Messier 33
Associated objects for Messier 33
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Messier 33