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Full database:

Entire DOCdb database of 18,816 objects.



NGC 3623 (7,755 of 18,816)


oc gc pln bn dn gx gxcl ast aka lost




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NGC 3623 (in Leo Triplet)

NGC 3623, Arp 317B, LEDA 34612, MCG+02-29-018, UGC 6328, Messier 65 (in Leo Triplet), h 854, GC 2373

RA: 11h 18m 55.78s
Dec: +13° 05′ 32.3″

Con: Leo
Ch: MSA:729, U2:191, SA:13


(reference key)

Type: galaxy (AGN LINER-type), Sa

Mag: B=9.6, V=?

Size: 8.709′ x 2.454′
PA: 174°

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Photos  (2)

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Historical observations

Lassell, W. (1866)

Bibcode: [1866MmRAS..36....1L]

Sketched and described.

Published comments

Arp (1966)

Together with NGC 3627 and NGC 3628 it is listed as No. 317 in Arp's "Atlas of Peculiar Galaxies" (Astrophysical Journal Supplement, vol. 14, 1966.)

Sandage & Tammann (1975)

Sandage, A. & Tammann, G. A. (1975) Steps toward the Hubble constant. V - The Hubble constant from nearby galaxies and the regularity of the local velocity field. ApJ, 196, 313-328. [1975ApJ...196..313S]

Sandage and Tammann (1975, Astrophysical Journal, 196, 313-328) includes this galaxy in the Leo Group. Members include NGC 3338, NGC 3351, NGC 3368, NGC 3377, NGC 3379, NGC 3384, NGC 3389, NGC 3412, NGC 3489, NGC 3593, NGC 3596, NGC 3605, NGC 3607, NGC 3608, NGC 3623, NGC 3626, NGC 3627, NGC 3628, NGC 3686 & NGC 3810.

Sulentic & Tifft (1973)

The RNGC (Sulentic and Tifft 1973) notes that this is a 10.5 mag galaxy. Their coded description reads S,EL,HISB,WDPERIPHLN.

NGC 3623 M-65 Donald J. Ware:"This galaxy is relatively large and bright, with a bright center and a stellar core. It is elongated in the north-south direction, and appears about 8'x2' in extent. It is in the same low power field of view as the next two objects."

Sandage, A. (1961) The Hubble Atlas of Galaxies

This galaxy appears on page 11 of "The Hubble Atlas of Galaxies" by Allan Sandage (1961, Washington, DC).

de Vaucouleurs, G. (1975) M66 Group

de Vaucouleurs, G. (1975) Nearby groups of galaxies. In: Kuiper, G. (ed) Stars and Stellar Systems. Volume 9: Galaxies and the Universe. Chapter 14, p557.

M66 Group: This is the well-known compact triplet of spirals including M65 (NGC 3623), M66 (NGC 3627) and NGC 3628 together with several outlying systems including probably NGC 3593, NGC 3596, and NGC 3666, and possibly NGC 3485, NGC 3489, NGC 3506 and NGC 3547.

Doig, P. (1925)

Doig, P. (1925) Notes on the nebulae and clusters in Webb's 'Celestial Objects for Common Telescopes' (Sixth edition, Vol.ii). Part II. M.N.R.A.S., 35(8), 280.

Modern observations

Hartung, E.J. (1968) Astron.Obj.South.Tel

Hartung notes: "a conspicuous haze at least 4' x 1' in pa 170 deg with bright central region . . the central axis appears to lie closer to the following edge because of a long dark absorption lane disclosed by photos near this edge, which however I have not seen as such. Even 7.5cm will show the elongated character of this nebula."

Brian Skiff

= M65

7x35mm - mod f, elong N-S w/mod concen to non*ar center. BS, 29Apr1992, TSP.

7cm - middle of three in size & brtness @ 30x. elong ~N-S, extending 1.5x distance out maj axis of m11.5 * off SW flank. halo elong 5:1. concen is mod-broad in halo, then strong-even in oval core (1/5 total length) to non*ar nuc. [sketch in notes for *] BS, 12Apr1992, Anderson Mesa.

Tom Lorenzin

Tom Lorenzin, in the electronic version of "1000+ The Amateur Astronomers' Field Guide to Deep Sky Observing", notes: "9.3M; 10' x 3' extent; large and bright with brighter center; very elongated with NNW-SSE orientation; !good supernova prospect! see photo at HAG-11; M-66 is 20' to ESE."

Danie L. Cronje


Danie Cronje, observing with 10x50 binoculars, notes that he couldn't see it from moderately light-polluted skies.

Contemporary observations

Auke Slotegraaf

2012 February 19, Sunday

Location: Paardeberg (ASSA Cape Centre dark sky site)[33:34.4S, 18:51.3E]

Time: 00:10 SAST

Binocs: 15x70 Celestron

NGC 3623 and NGC 3627 are two oval (3:1 ratio) smudges, lying in parallel, readily seen. NGC 3623 is elongated towards a 7th mag star (HD 98388) 20' north, and is the fainter of the two galaxies. NGC 3627 is brighter, and seems to have one or two small stars involved.

The pair is easy to find. Start from Chort (theta Leo, 3.3V), the faintest star of Leo's Triangle. They lie in the same binocular field as the star, less than 3 degrees to the south-east.

1994 February 13

1994-02-13 02:00 Die Boord, 11x80's tripod-mounted. Readily seen as a faint elongated glow. Fainter than NGC 3627 (M66) nearby.

Magda Streicher

(no date)

Alldays (22.50S, 20.12E, 770m).

12-inch f/10 SCT (218x, 346x)

Large, bright more extended than M66 that is a little wider. Very much defused, knotted uneven in appearance, and brightens up to the middle. Little structure. Stars form a bridge between M65 and M66. Fairly bright, oval core with fainter extensions that give the galaxy a very gentle S curve. Elongate nearly north south. With high power M65 seem to lose its curve. And you can spot a faint star gleaming along the galaxy's southwest edge. NGC 3628 lies just 36' north of M66.Its light is spread over a larger area. It shows up well Appears very long and thi, brightening gradually to a slightly brighter elongated core. The needle shape of this galaxy runs east southeast to west-northwest and it appears about eight times longer than it is wide. One of the prettiest flat galaxies in the sky.

Richard Ford

2010 May,15 Saturday


Instrument:12"Dobsonian Reflector Telescope.

Sky Conditions:The fainter parts of the Milky Way are barely visible.

Transparency of the Sky:Haziness only visible on the horizon.

Seeing:Atmosphere stable with little interference.

Limiting Magnitude:4.9.

First Impression:Galaxy.



Chart Number:No.10(Extract taken out of "Atlas of the Night Sky").

Size:26mm Eyepiece:Field Of View:57'/8=7.1'.

20mm Eyepiece:Field Of View:50'/7=7.1'.



Size in Arc Minutes:7.1'.


Brightness Profile:Low Surface Brightness.

Challenge Rating:A spectacular sight to observe this galaxy in a large telescope under crisp clear dark skies.



This galaxy is oval and well defined as a bright spiral galaxy with some dust lanes on the outskirts.This galaxy's spiral-like structure is easily noticeable with a bright central nucleus.Very close to this galaxy,I have found a few faint third to fifth magnitude stars.No darker areas as far as I am concerned have been found.I have found some areas of uneven brightness around the outskirts of this galaxy,although towards the central nucleus areas of even brightness are noted.

Tom Bryant

2007-05-11 23:00:00

Observing site: Pinnacles overlook

Telescope: C-8

[11h 18m 54s, 13 5m 0s] A bright streak in the sky, like M 66

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