Robert's Quintet, NGC 92's tail

[akarsh]

Hi

I just came across this group randomly while testing KStars (!)
https://archive.stsci.edu/cgi-bin/dss_search?v=poss2ukstu_blue&r=00+21+31.70&d=-48+37+29.1&e=J2000&h=15.0&w=15.0&f=gif&c=none&fov=NONE&v3=

Apparently, this is "Robert's Quartet". [ https://en.wikipedia.org/wiki/Robert's_Quartet ]
I hadn't heard of it at all, probably because of it's very southern declination, which prevents it from crossing airmass 2.4 almost from Texas latitudes even.

NGC 92 seems to have an interesting tidal tail.

I'm wondering if anyone has grabbed it in the forum. It being in the NGC, it's almost certain that Steve has seen it. Comparing with the Mice galaxies (which sport pretty much the only tidal tail I'm aware of that's accessible in an 18"), it seems like it would need at least a 25~30" from 30 °N latitude?

Clear Skies

Regards
Akarsh

[Steve Gottlieb]

I didn't have the best transparency (high humidity/dew) when I made these observations, but I didn't notice NGC 92's tail in an observation from Coonabarabran with a 30" at 429x. By the way, the group is also called Rose 34 and the Phoenix Quartet.

NGC 87: fairly faint, irregularly round, 0.7' diameter, low even surface brightness. Westernmost and second faintest in a compact quart with NGC 88 1.5' SE, NGC 89 2.8' SE and NGC 92 2.9' E. The arrangement is distinctive with the three brighter galaxies (NGC 87/89/92) arranged in an equilateral triangle with NGC 88 in the center, forming a "Y" or propeller shape. ESO 194-13 lies 12' ENE of the quartet.

NGC 88: faint, small, slightly elongated NW-SE, very small bright core. An extremely faint star is attached at the SW end. This galaxy is the faintest in the quartet.

NGC 89: moderately bright, elongated 2:1 NW-SE, 1.0'x0.5', very small slightly brighter core, faint stellar nucleus. Has a slightly higher surface brightness than NGC 92.

NGC 92: moderately bright (brightest in quartet), elongated 2:1 NW-SE, 1.2'x0.6', broad concentration to a bright core. A faint tidal tail to the SE was not seen.

ESO 194-013: moderately bright, elongated 4:3 SW-NE, 0.9'x0.7', broad concentration with a slightly brighter core but no distinct zones. A distinctive string of three mag 13 stars [length 1.4'] is centered 2' E.

[akarsh]

Thank you for the information, Steve! This is intriguing, because given how POSS usually translates to observability on Jimi's telescope when it comes to tidal tails, I'd think it should be possible in a 48". But then again, a 48" is quite a lot more than a 30"...

Clear Skies

Regards
Akarsh

[Uwe Glahn]

No tidal tail with 17-inch at all. But you are right, it seems to be a possible structure. Next time at the 28-inch (http://www.licht-stimmungen.de/01_sub_pages_astro/pics_astro/beobachtungsberichte_2015/Gamsberg/Gamsberg/IMG_0352_comp1200.jpg) I will give it a try.

17", 260x, NELM 7m+ (Namibia)
1968