Object of the Week November 11th 2018 - NGC 877

[obrazell]

NGC 877 also known as MCG 2-6-58, UGC 1768, PGC 8775

Galaxy

R.A.: 02h17m59.4s

Dec.: +14°32'40"

Magnitude: 12.50 B

Size: 2.1'x 1.6'

The galaxies in the small group around NGC 877 will provide a challenge to observers, not least because of the two relatively bright stars in the field.
Apart from NGC 877 the other NGC galaxies in the area are NGC’s 870, 871 and 876. NGC 877 and 871 were discovered by William Herschel in 1784
but it took the much greater light gathering power of the 72” at Birr for Mitchell to discover NGC 870 and 876 in 1854. NGC 877 was one of the
objects that the Rosse team thought were spiral in nature, a deduction that was pretty accurate in this case as in fact NGC 877 is a face on spiral.
NGC 877 also shows signs of interacting with the nearby edge on spiral NGC 876 with one of NGC 877’s spiral arms showing some signs of distortion
due to the tidal forces in this interaction. NGC 877 is classified as a Low Surface Brightness (LSB) galaxy so its nucleus may be easy to see but
the spiral arms will be more of a challenge. The galaxies NGC 877, 876 and 871 along with some of fainter galaxies in the field form a true
interacting group and radio measurements in the 21cm band of neutral hydrogen show signs of some of the interactions in the group. The group,
also catalogued as LGG 53, would appear to contain 8 galaxies and lies at a distance of perhaps 50 Mpc. The whole group is contained inside a
large neutral hydrogen envelope which contains a number of tidal features. It is not clear that NGC 870 is physically associated with the other
galaxies. Steve Gottlieb reports that the fainter NGC galaxies in this group are a challenge for an 18” scope. In the recently published
IDSFG (Interstellarum Deep Sky Field Guide) Uwe Glahn does include a drawing of 877 and 876 with a 16” scope showing some detail in both.
There is a nice image of the group at http://www.caelumobservatory.com/gallery/n877.shtml. For more of a challenge try finding the face on
LSB spiral UGC 1761 in the same field.

ngc877_annot.jpg

As always give it a go and let us know what you find

[Bertrand Laville]

Only a very old observation with a 10", LX200/254, in a rural sky, NELM 6.4, SQM 21.5 estimated

X104 NGC 877 comes to light well.*It is is seen in direct vision, but with difficulties.*Lengthened halo, a/b ~ 2.5, in PA ~ 140 °.*D ~ 1.6 ' x 0.75 '*
Prominent bar on all the length of the halo, in the same PA 140 °, d ~ 1.5 ' x 0.5 '. Rather difficult stellar nucleus*, in the center of the bar, m ~ 14.0v*. D *, in border S of the halo, is estimated m12.5v*

X141 E* is estimated 13.8-14.0v*. F* was suspected without knowing it (I took her for NGC 876), and validated by Guide8 / DSS.
NGC 876 and other galaies aren't seen.
E* GSC 637 620, m13.7B, F* Ucac2 1263152248, m14.45V.

Clear skies
Bertrand
http://www.deepsky-drawings.com/

[Steve Gottlieb]

This is a nice visual challenge as the brightest NGC 877 is visible in a 6" but NGC 870 will probably be challenging (V = 15.5) in an 18". By the way, NGC 870 is not a member of the group that Owen mentions (LGG 53) as its redshift is ~ 4.5x higher and the light-travel time is on the order of 750 million years.

[Uwe Glahn]

Steve is right, NGC 876 is a tough object.

With 16-inch I noted: soft seeing; NGC 877 bright, large, 2:3 SE-NW elongated; faint arm to the NW side suggested, visible as detail beyond a faint dark lane along the SW side; more detail possible with better seeing; with larger EP NGC 876 is visible as a faint streak with 4:1 elongation and longish nucleus

sktech: 16", 180x, NELM 6m5+, Seeing IV
NGC876_NGC877.jpg