June Astronomy: NGC 5907

Image Credit: R. Jay GaBany

Image Credit: R. Jay GaBany

June’s astro-subject is a wonderful galaxy in the constellation Draco, near the border of Bootes. It is a classic “edge-on” galaxy, as we see it along the thin axis of its spiral arms, rather than face-on.

Designated as NGC 5907, it is a bright and easy galaxy to observe, even in the most modest telescope. It’s large in apparent size, by galaxy standards, at 12.7′ x 1.4′, and slightly inclined, but still easily qualifying as a thin edge-on galaxy. In the image below you can see the dust lane along the edge, and some of its tidal trail from interacting with another galaxy.

NGC 5907 is 50 million light years from Earth, and is part of the NGC 5866 group, which comprises seven, or perhaps eight galaxies that are gravitationally bound together traveling through space. The most notable member of the group is NGC 5866, also thought to be the “Missing Messier,” M102.

The chart below shows some of the galaxies in proximity of NGC 5907 to NGC 5866.

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Chart from Megastar

All the galaxies shown above are of about equal magnitude, so if you find NGC 5907 you should be able to galaxy-hop to the others.

To get to NGC 5907, if you are finding it manually, here is an easy star hop:

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Find the Big Dipper and the Little Dipper in the north. The end star in the handle of the Little Dipper is our pole star, Polaris. Use the end of the Little Dipper’s cup stars, the two brightest, and look for the middle star in the handle of the Big Dipper. About halfway between them is a bright star in the constellation Draco. From there, hop to the next bright star in Draco, away from the Dippers, and you’re in the neighborhood. A short hop from there, maybe 1/5th the distance you just traversed, and you will be very close to the target.

Also known as the Knife Edge Galaxy, for obvious reasons, the galaxy was discovered in 1788 by Sir William Herschel. Here is a photo showing it in a wider field, and more true to how you might see it (but dimmer and without color) in your telescope:

NGC 5907 image by Dr. James Dire

NGC 5907 image by Dr. James Dire

Compare your views and observation notes from these observation locations:

Finland:

With a 4.5 inch Orion SkyQuest @ 114x (37′), NGC 5907 appears as a beautiful, shard needle in a nearly empty field. It is clearly elongated in NW-SE direction and roughly 9′ x 1′ in size. The central bulge fairly apparent and slightly brighter than the rest of the galaxy. Low surface brightness object.

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North Carolina:

Using a 10-inch reflector, this galaxy appears as a faint streak of light with a subtle brightening in the central region. The overall surface brightness is low, and if transparency is not good this galaxy can be very difficult. The galaxy appears much fainter than the cataloged 10.4 magnitude. At 200x, a faint star could be seen just off the west edge of the core, and another very close to the NE tip. The dust-lane as seen in photographs is very difficult, but has been reported by amateurs using larger backyard telescopes.

For larger apertures, here are observing notes from Northern California:

17.5″: fairly bright, extremely large edge-on 9:1 NNW-SSE, extends to roughly 13’x1.5′. Contains a bright core with an almost stellar nucleus. A mag 14 star lies 1.1′ W of center.

13″: Very large, very elongated, narrow streak, bright core, faint star is W of the core.

Happy viewing!

Crash

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