Hoag`s Object

OBSERVING REPORT

PGC 54559 - HOAG`S OBJECT in Serpens Caput

Date: August 11, 2010
Time: -
Telescope: 24" (61cm.) f/4
Observer: Leo Cavagnaro

Click on the image to enlarge

Finder Chart

How to find it,

About 6° 33' southwest of the star Alphecca, α Coronae Borealis (visual magnitude 2.2).

About 3° 53' southeast of the star 45 Bootis(visual magnitude 4.9).

Stars in map up to visual magnitude 6.0

Situated in Serpens Caput, this prototype of ring galaxies was discovered by Hoag (1950). It is an obscure target for amateur observers. 

The Hoag`s Object, a peculiar galaxy.

The presence of a blue detached ring, viewed face-on, around a red central core gives Hoag’s Object its unique appearance. Hα emission is detected along the entire ring, at least to the limit of the luminous stellar component. In the paper "Hoag’s Object: Evidence for Cold Accretion onto an Elliptical Galaxy" by I. Finkelman, A. Moiseev, N. Brosch, and I. Katkov (2011) the authors conclude that the collisional ring scenario is not responsible for forming genuine Hoag-type galaxies (Finkelman & Brosch 2011).

There was a first observation of this object at low magnification (90x). I could identify the "Y-shaped" pattern of stars in the field of view of the telescope which helped to find the accurate zone where PGC 54559 inhabits. At higher magnification (153x) the galaxy is visible using averted vision, looking like a very small hazy spot rather round in shape, with smooth brightness.

At 271x, the galaxy is a hard object to see even using averted vision. The appearance is similar to that obtained at 90x.