Object of the Week June 22, 2014 - NGC 6028 - The Nearest and Brightest Hoag Ring

NGC 6028

RA/Dec: 16 01 28.9 +19 21 34
Size: 1.3'x1.2'
Mag: V = 13.5, B = 14.4
Type: S0-a Ring
Aliases: NGC 6046 = UGC 10135 = MCG +03-41-043 = CGCG 108-063 = I Zw 133 = PGC 56716

At a distance of roughly 200 million l.y., NGC 6028 is the nearest Hoag-type Ring galaxy. At 1/3 the distance of Hoag's Ring, it is significantly brighter but gets little publicity among amateurs -- probably because it has no iconic HST image.

French astronomer Guillaume Bigourdan found NGC 6028 on 4 May 1886 with the 12-inch refractor at the Paris Observatory. But it was William Herschel who originally discovered this galaxy on 14 Mar 1784 and recorded "A nebula suspected by 157 and the suspicion strengthened by 240, but the latter power does not remove all doubt. It follows 3 pretty bright stars making an arch [concave towards np or nnp direction by a diagram], south of which arch there is a still brighter star."

Herschel catalogued this object as H. III 33 (and later by Dreyer as NGC 6046), but unfortunately his position was 3.5 min of RA too far east. Modern sources may show NGC 6046 as nonexistent or lost, but Harold Corwin uncovered NGC 6046 = NGC 6028.

How close is this object in appearance to Hoag's Ring? Well, here's the SDSS image --

Attachment 1279

The core of the galaxy should show up in a 10-inch scope in good conditions, but I'm very curious how small a scope will display the outer ring? I've yet to look for the outer detached ring in my 24", but here are my notes in Jimi's 48-inch in 2012. By the way, while you're in the area, you should pick up CGCG 108-053, just 7' northwest of NGC 6028.

"This Hoag-type ring galaxy contains a bright, very small core, ~18" diameter. A star is right at the south edge of the core. A 1' diameter detached outer ring would occasionally pop into view and the ring appeared as a slightly elongated Cheerio surrounding the core!"

Attachment 1280

"GIVE IT A GO AND LET US KNOW"
GOOD LUCK AND GREAT VIEWING!

No luck detecting the outer ring using my 12" SCT under very good conditions in 2011 (179x / 27'):

A small, round patch, brighter in a round central part (clear without using AV), using AV the nucleus is faintly visible. The faint outer ring of the galaxy is not visible.
To the SSW is a mag. 15 star, twice that distance to the SW is a mag. 14 star, a little farther to the WNW is a mag. 10 star.
1/3 Fov to the NW is a very faint, slightly east to west elongated patch (=MCG+03-41-033), even in brightness.

Also no luck with the ring with 27" under normal transparency.

I noted:
27", 293x-419x, NELM 6m5+, Seeing III - very bright and small core; S following very near star, looks like a double star together with the bright core; uncertainty a very faint glow around the core with 293x, but definitely no ring structure or ring fragments visible

When I look onto the blue POSS plates I just wondering why I could not detect the ring. The galaxy is on my list to revisit, maybe or hopefully under better conditions.

The detached ring in NGC 6028 seems like it should be much easier to view than Hoag's Ring, though sometimes the DSS appearance can be deceiving. Any other failed or successful attempts?

May 10, 2010, Fort Davis, Tx
Trans. 8/10, Seeing 7/10
30" f/4.5, 226x - 550x

Small, dim galaxy with a bright core. Looked like a double star with a nebulous disk around it.

From my "magnum opus" (p. 263): “Visually, the galaxy is quite small and faint, appearing as a roundish patch of light which is a little brighter to the middle and moderately well defined.” That was with a 15-inch reflector. Certainly no ring in that aperture.

Should be clear tonight, but the sky won't nearly be truly dark in the Great White North... if I get a chance, I'll give it a go with the 18-inch.

Went out tonight and with a limiting magnitude of about +5.2 visually at midnight (it got a little darker by 1:00 a.m. local time, maybe about +5.5 mag. overhead) I observed NGC6028 as a slightly oval patch of light, extended E/W, suspected a faint star south of the core at 295x, but couldn't hold it. No ring... I suspect the minimum aperture to observe the ring might be 48-inches (ha,ha). To give you an idea of the sky conditions, I observed NGC5991, IC4553 and IC4554, NGC5975 and MCG+4-37-21, UGC9958, UGC10020 and NGC5972... tried (not too hard) for NGC5977 but was unsuccessful.

Steve,

yesterday I had the chance to revisit this galaxy under much better transparency but poor seeing with the 27".

I noted: 27", 293x-419x, NELM 6m5+, Seeing IV - small and bright core; even with searching eyepiece a faint halo could be seen around the core; best view with 293x; halo 2:3 N-S elongated and visible with averted vision; no ring structure or fragments; faint star just S of the core, under poor seeing it looks like a fuzzy double star

Pretty the same results as Jim and again unfortunately no ring structure. Maybe the ring is to broad to see it as a ring.

Object was easily located in my 18" under quite good transparency. It did not appear perfectly round, rather ellipsoid at 275X. I tried higher magnifications but the seeing could not suport them.

Attachment 1281

I went after this object last Saturday at Shot Rock. The conditions were not as good as usual due to higher than average level of particulate matter in the air.

Anyhow when I sweeping for it, it was immediately picked up as a "double" star at low powers, a second later the
compact halo is obvious. The ring was not seen. I used my 22" scope and between 230 and 575x.

I had a nice view of NGC 6028 at GSSP with a 24 " Star structure W/ Kennedy Mirror . At moments of good seeing the ring structure would pop in to view with direct vision. I have seen this ring many times with my old 25" F/5 over the years.

I didn't have any luck with the ring at TSP 2014 with my 18". (I was looking at this as part of the old TSP 2000 "Rings over TSP" list)