M33 - NGC 598
DSS image of M33
Overlaid DSS image of M33, 120' x 120' with north at top and west to the right

Aladin viewer for the region around M33
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°
RA (2000)  1h 33' 50.9"
Dec (2000)  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

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

- None

Andrew Cooper
Aug 21, 2017    Grants Spring, OR (map)
76mm f/6 APO, TeleVue-76 @ 30x

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

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

Rev. T.W. Webb
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
Other Data Sources for M33
Associated objects for M33
Nearby objects for M33
Acknowledgements and Credits...

Drawings, descriptions and CCD photos are copyright Andrew Cooper unless otherwise noted, no usage without permission.

Positional and some physical information is from the NASA/IPAC Extragalactic Database (NED) which is operated by the Jet Propulsion Laboratory, California Institute of Technology, under contract with the National Aeronautics and Space Administration.

Additional object data from the SIMBAD database, operated at CDS, Strasbourg, France.

The Digitized Sky Survey was produced at the Space Telescope Science Institute under U.S. Government grant NAG W-2166. The images of these surveys are based on photographic data obtained using the Oschin Schmidt Telescope on Palomar Mountain and the UK Schmidt Telescope.

Dark nebulae data from E.E. Barnard, A Photographic Atlas of Selected Regions of the Milky Way. Ed. Edwin B. Frost and Mary R. Calvert. Carnegie Institution of Washington, 1927

Object descriptions of Rev. Webb from Celestial Objects for Common Telescopes sixth edition, Rev. T.W. Webb, 1917, edited by Rev T.E.Espin.

NGC & IC object notes from Harold Corwin licensed under a Creative Commons Attribution-ShareAlike 3.0 Unported License. Additional supplementary material for NGC and IC catalog objects from Courtney Seligman with non-commercial use allowed, found at https://cseligman.com