By Brian Cuthbertson
Let’s face it: November is galaxy time. To be sure, the Milky Way’s outer rim dominates the far north, and its winter spectacles are rising with Orion and friends in the east. But a vast swath of the November sky is a deep space window – Pegasus, Aquarius, Pisces, Cetus, Eridanus – all are galaxy lands. So we’ll go with the flow, and it’s all fascinating, if not a bit humbling; egos don’t fare too well against an endless sea of galaxies. Below are pointers to a few, but there’s an infinity of more if you’re up for it. Enjoy!
M74 rating: EASY
NGC 628, face-on spiral galaxy
RA 1h 36.7m Dec +15d 47.0′ (2000)
Magnitude 9.2
Easily found less than 2 degrees west of 3.6-magnitude ETA Piscium, M74 is a nearly perfect example of a face-on type Sc spiral galaxy. Partly because of this face-on orientation and low surface brightness, it is among the faintest and most elusive galaxies in Messier’s catalog, and is often seen best with low-power, wide-field instruments. For this reason it is sometimes nicknamed the “Phantom galaxy.”
M74 is notable for its bright starlike nucleus, surrounded by a diffuse glow about 5′ in diameter. The nucleus is so starlike that it was cataloged in the 19th century Bonner Durchmusterung (BD) star atlas as a star!
Visually similar in many ways to better known spiral M101, M74 is somewhat more regular and symmetrical. In digital images its spiral arms can be traced around the system for 500 degrees. Both M74 and M101, as well as Messier galaxies M51 and M81, are called “grand design” spiral galaxies.”Grand design” spirals typically have prominent and well-defined spiral arms – usually two – as opposed to multi-armed and flocculent spirals which have subtler structural features. Only 10% of all spirals are “grand design” spirals. Multi-armed spirals are the most common spiral type, composing about 60% of spirals. Flocculent spirals, characterized by discontinuous arms, make up the remaining 30% of spirals.
M74 lies about 35 million light-years away and is about the same size as the Milky Way (100,000 light-years across).
NGC 1052 rating MEDIUM
active galaxy in Cetus
RA 02h 40.4m Dec -8d 26.1′ (2000)
Magnitude 10.8
NGC 1052 is an active radio galaxy that lies in Cetus about 7.5 degrees SE of well-known long-period variable Mira (Omicron Ceti). Visually the galaxy is unimpressive in smaller amateur scopes. A 6-inch shows only a small circular spot with a sharply brighter stellar nucleus. A 10-inch shows a spot about 1′ in diameter with a stellar nucleus. A 12-inch will pick up a 25″ core centered on the nucleus. NGC 1052’s nucleus is the LINER type. LINER (low ionization nuclear emission region) galaxies are very common, composing about 1/3 of all nearby galaxies (within 20-40 Mpc). LINER energy sources have been a matter of debate. Some professionals propose supermassive black holes as the energy source. Others believe that star formation regions are responsible.
NGC 1052 also has two small jets emerging from its LINER nucleus, as well as a very extended disk of neutral hydrogen, far bigger than the galaxy itself. All these features suggest that a gas-rich galaxy collided and merged with it perhaps a billion years ago. The colliding galaxy may have come from the group of which NGC 1052 is the brightest member. Other galaxies in the NGC 1052 group include NGC 1042 (actually a bit bigger, but fainter at 10.8), NGC 1035 (mag. 12.8) and the even fainter systems NGC 1047 and NGC 1048. Take a crack at these if you really like a challenge.
NGC 520 rating HARD
interacting galaxies in Psc
RA 01h 24.6m Dec +3d 47.6′ (2000)
Magnitude 11.2
NGC 520 is perhaps the best-known peculiar galaxy in the autumn evening sky, and one of the brightest interacting systems in the entire sky. It’s a bizarrely warped system in SW Pisces; you can find it just under 10 degrees (~35 minutes) west of 3.8 magnitude Alrischa – Alpha Piscium, which itself sits almost exactly in the SW corner of Pisces.
Also known as Arp 157, NGC 520 consists of a distorted main disk that supposedly represents the partial merger of two similar-sized disk galaxies seen edge-on, a collision that began roughly 300 million years ago. In addition, the system has tidal tails apparently caused by the close passage of a third galaxy, UGC 957.
Seeing the wealth of detail in this system generally requires dark skies and larger scopes. A 10-inch class scope will show an irregular 1.2×0.5′ glow with a squarish outline, composed of two brighter lobes separated by a slight darkening. The NW lobe is the brighter, and contains several bright spots. A 17-inch scope at 260x will pick up the irregular dust lane bisecting a bright, roughly polygon-shaped disk, and a 24-inch can detect hints of delicate tidal plumes coming off the ends of the bright disk.
Not surprisingly, NGC 520 is in the IRAS catalog of infrared sources, which indicates massive star formation as the combined system evolves toward what will probably be an elliptical galaxy. Some astronomers predict that this is the same fate that awaits our Milky Way and the Andromeda galaxy M31 in about 5 billion years. NGC 520 has a diameter of roughly 150,000 light-years and lies about 100 million light years away.
