Object of the Week January 23, 2022 – NGC 1532

Name: NGC 1532 = ESO 359-027 = MCG -05-11-002 = AM 0410-330 = LGG 111-003 = PGC 14638
R.A.: 04h 12m 04.3s
Dec.: -32° 52' 29" (2000)
Con: Eridanus
Type: SB(s)b pec
Size: 12.6'x3.3'
Magnitudes: 9.9V, 10.7B; Surf Br: 13.8 mag/arcmin²

James Dunlop discovered this beauty on 29 Oct 1826 with his 9-inch f/12 speculum reflector. He described "an extremely faint ill-defined nebula, rather elongated in the direction of the meridian [N-S], gradually a little brighter towards the centre." His notes mention it is situated southwest of a pretty bright star, which is mag 7.0 HD 26799.

John Herschel observed this showpiece spiral on 3 differents sweeps with his 18" reflector in South Africa. On his first observation (19 Oct 1835) he called it "Bright, very large, very much elongated, 5' long; A fine and curious object. The following and brighter of two [with NGC 1531]. In the ray is either a very faint star or a knot in the nebula."

The galaxy has hosted two supernovae. Type II SN 1981A was the first of many supernovae discoveries by the great visual observer Rev. Robert Evans. SN 2016 iae was a type Ic supernova discovered on 7 Nov 2016, which I viewed three weeks later.

This image is from the Carnegie-Irvine Survey. The notes mention "The unusual plumes in NGC 1532 suggest a tidal distortion due to an encounter. The evident candidate responsible for the perturbation is the amorphous companion NGC 1531, whose morphology is of the same class as M82. The two galaxies form a physical pair"

Attachment 4591

About a year ago in my 14.5", I logged NGC 1532 as a "bright, very large edge-on 5:1 SW-NE, ~6'x1.2', forms an impressive pair with NGC 1531. Contains a very bright core that increases towards the center.".

The view through Jimi Lowrey's 48" was spectacular --

This showpiece edge-on stretched 7'x1.2', tilting SW-NE. The galaxy is sharply concentrated with a large, elongated, very bright core that was mottled and increased to the center. The rest of the galaxy was knotty, streaky and mottled. A striking dust lane runs along the major axis, slicing the galaxy asymmetrically into two parts to the south of the core. The dust lane expands to a larger, elongated (dark) patch on the NE side of the core. The section to the south of the dust lane is much thinner and brightens to a prominent, very bright knotty 1.5' streak on the SW end [this is the brightest part of a tidal tail extending towards NGC 1531]. A very faint star (B = 18.2) is close to the southwest tip of the bright streak. The fainter strip of galaxy south of the dust lane near the core appears patchy, probably due to dust and star-forming knots. Just northwest of the core is NGC 1531, a bright elliptical that angles perpendicular to the core and forms a striking pair.

As always,

"Give it a go and let us know!
Good luck and great viewing!"

Attachment 4592

Hi,here's my observation from 1/3/2008 : ngc 1532 and 1531 galaxy pair in Eridanus ; magnitude: 9.9 size and 12.17 : 12.6' x 3.3' ; beautiful pair, ngc 1532 has a bright core and is very elongated, dust lane hinted with averted vision. Attachment 4593

Back in 2012 with a 22", 337x and a Galaxy Contrast Enhancement filter, I could see both at right angles to each other, NGC 1532 being much larger than 1531. Unfortunately, at 16 degrees altitude and almost directly South, I could not see much detail in either as described above.

I have an observation from 2008 (November 1) that I made at the late, lamented New Mexico Skies with a 25-inch F/5 reflector which I believe was a Telekit. Regrettably, I don’t have a scan of the sketch I made, but Raul’s sketch above is quite similar, if a little less detailed. My notes: “This is a bright pair of galaxies well seen at medium magnification. NGC 1531 is smaller and slightly fainter; a well-defined elongated object of high surface brightness, evenly illuminated and oriented NW/SE. NGC 1532 is very large and bright, a well-defined, almost edge-on galaxy with a bright elongated core that is the same size as the disk of NGC 1531. NGC 1532’s disk is bright and much extended, sharply defined along the NW flank and a little more diffuse to the SE. Dark patches are suspected on both sides of the core. The one to the NE splits the suspected spiral arm into two while SW of the core a tiny, brighter enhancement is suspected. NGC 1532 is oriented NE/SW. Magnification: 195x”

This pair was a definite highlight of the Dunlop catalog for me with my travel Mak from Australia, but, objectively, I only saw as much of it as Al managed from our home latitude.

Got two observations from Namibia but no sketch.

12", 150x, NELM 7m0+: large edge-on with wide extensions; at the long SE side dark band; NGC 1531 directly NW; somewhat offset IC 2041 visible

14.5", very bright, 4:1 elongated glow with shiny central region; directly NW of the centre and 90° tilted, the small NGC 1531 becomes visible; dark band indicated; brighter longish HII region in the SW part

I observed this galaxy pair tonight with my 20" dob from the Rio Hurtado valley in Chile.

NGC 1531: At 83x and 320x a small oval with a brighter center with the major axis pointing at NGC 1532.
NGC 1532: At 83x a thin galaxy with a stellar center. At 320x a long, thin smear with a stellar core and a dark lane running through it. On one end there is a thin bright lane in the galaxy. Occasionally a very faint smudge is visible next to the core.