Two exotics gems: MCG-01-24-001 & UGC 5373 Sextan's Dwarf

[javier_gl]

Hi all

Last friday my wife Conchi and me enjoyed an humid but decently dark (21.6 SQM) observing night at our observatory in La Alcarria region, about 150 Km NE from Madrid, Spain.

After observing with the 24" f/4 several well known galaxies the first night hours, it was time to try some more challenging deep sky objects. My planetary software (SkyMap 11) showed a pretty DSS image of MCG-01-24-001, a galaxy in Hydra.

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At first, I thought it was a mislabeling in the software, since such bright galaxy deserves a NGC entry but, when the telescope aimed at the correct coordinates, the field showed a bright 9mag star in the center, so that it was clear that the relative bright galaxy was almost fully obscured into the star glare.

Direct vision throught an Ethos 13 (220x) hardly ever shows a very faint asymmetrical halo around the star; with averted vision, the galaxy appears easily as a luminous band 6' long just over the star. Changing between DV and AV makes the galaxy blinks as the well known Cygnus planetary; a very curious "Blinking Galaxy".


The second faint object was UGC 5373, the Sextan's Dwarf.

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In this case the DSS image shows what you get at the eyepiece: a very faint glow, but several faint knots were detected at the very vision limit. Indeed, Sextan's Dwarf looks me more like a faint Palomar cluster than a galaxy.

If any of you have seen these galaxies, what is your impression about their blinking and globular appearance?

[Steve Gottlieb]

I didn't notice a blinking effect with UGCA 150 = MCG-01-24-001, but it's still a cool galaxy
18" (2/23/06): this unusual galaxy appears as a fairly faint edge-on oriented SW-NE, ~2.0'x0.4'. Mag 9.0 HD 78953 is strikingly superimposed just southwest of the center and detracts from viewing. Still, the galaxy is easily visible as a fairly faint streak extending mostly to the NE of the star! A 13" pair of mag of 14/15 stars is superimposed on the NE extension. Located 19' ESE of mag 5.5 20 Hydrae.

I can see the see the similarity, though, with UGC 5373 and a low surface brightness globular cluster.
18" (2/19/09): easily visible at 175x as a large, low surface brightness, oval patch, extended 3:2 NW-SE, ~3.0'x1.9'. The glow is nearly parallel to two mag 13 stars off the NE side and extends roughly the separation of these stars (3'). This dwarf galaxy has only a broad, weak concentration with a slightly brighter core and an ill-defined edge to the halo as it fades at the periphery. Still, the surface brightness is slightly irregular with a hint of mottling. Located 8' NE of mag 7.7 HD 86610.

[Uwe Glahn]

Like Steve I didn't notice any blinking effect. But your "exotic picks" are still interesting.

UGCA 150
This galaxy belongs also to the RFGC (Revised Flat Galaxy Catalogue). Because of this reason I visited the galaxy a few years ago with my 16". I noted: in direct neighborhood of a 9mag star which outshines and disturb the thin morpology of the galaxy; visible from the overall view eyepiece (51x); could not detect the whole size because of the bright star; only the brighter middle of the galaxy is visible without problems; three stars (one DS) within the galaxy

Sextans B
I visited this guy because of the membership of the NGC 3109 group (near group of "our" Local Group). Not to confuse with Sextans A (UGCA 205). I noted: 4", 44x, NELM 6m5+ - eben with low power a low surface glow is visible; best view with 44x; faint but could hold glow with averted vision without problems; diffuse edges; round and with bigger aperture: 20", NELM 6m5+ - even with overview eyepiece brighter glow near the 7,7mag bright HD 86610; best view with middle power; round; 3' size; structureless