Observing NGC 128

I took this image of the NGC 128 field on September 10th with a remote 17-inch astrograph located in Australia (T32), on the iTelescope.net network. It is a stack of five 3-minute exposures in the Luminosity filter plus three 3-minute exposures in the Red and Blue (5X180L + 3X180RB). I used SkyTools 3 to plan the imaging session. NGC 128 is the larger galaxy on the right with the "X" shape at the center.

NGC 128 is a tiny edge-on spiral galaxy with an unusual twist. It has been distorted by tidal interaction with its neighboring galaxies, resulting in an "X" shape near the center. Walter Scott Houston wrote that he was able to view this galaxy in his 5-inch from a dark site. An 8 to 10 inch instrument will show the peculiar shape at the center, which may appear to be box-like in the eyepiece. Be sure to use at least 200x, and observe when very high in the sky on a night of good seeing (steady air).

Computer modeling has shown that the peculiar "X" shape can be attributed to the merger or accretion of a small galaxy. In other words, NGC 128 ate one of it's neighbors. The shape is made of tidally distorted disk material from the larger galaxy.

There are quite a few tiny galaxies visible in this field in my 18-inch. NGC 128 is the brightest, with the nearby NGC 125 coming in a close second. Due to the small size of NGC 128, I used 430x for the best view. It appeared as an irregular shaped, elongated smudge with two attendant smudges to either side (NGC 127 & NGC 130). The main portion appeared to be box like, wider at the north end. It had that irregular, speckled look that comes when there is detail beyond your ability to resolve. On seeing this, it was easy for me to understand how the great observers of previous centuries imagined all nebulae to be made up of unresolved stars, something that happens to be true in the case of galaxies such as this one, although here the "speckling" is more attributable to larger scale structure in the galaxy.

The field depicted by SkyTools 3 in a 10-inch f/4.5 at 75x. North is down and east is to the right.

The galaxies that flank NGC 128 (NGC 127 and NGC 130) are likely nearby in space as they all have similar redshifts, so they are at roughly the same distance. The same can be said of the other galaxies nearby, such as NGC 125 and NGC 126. Together, these galaxies form a cluster, loosely referred to as the NGC 128 group.

Going Beyond the Messier and Caldwell Catalogs

You won't find NGC 128 in the Messier list, yet it is detectable in a five-inch telescope from a dark site. The main reason most observers have never hunted it down is it's relative obscurity.

Amateur astronomy can sometimes get stuck in a rut. Beginning observers start with the Messier or Caldwell objects, and some never go beyond them. For those who do go deeper, a natural starting point is the observations of the great visual observers of the 18th and 19th centuries, which were compiled in the NGC catalog. But even they didn't spot every observable object in the sky. Just as the beautiful galaxy NGC 253 is not observed as often as it deserves to be simply because it does not appear in the Messier catalog, there are bright or interesting objects that don't get much attention because they aren't found in the NGC/IC.

One of the purposes of SkyTools is to take serious observers to the next level--beyond the confines of even the NGC/IC catalogs. Here are some of the ways it can do this:

SkyTools has large and highly corrected databases from a combination of many sources, not limited to the NGC catalog or any other single source.
The ability of SkyTools to accurately determine if any type of object is detectable in the eyepiece of your telescope, under your observing conditions, allows it to break the boundaries of catalogs like the Messier or NGC by simply asking, "is this object detectable?" Other products make gimmicky or generic predictions of visibility. SkyTools takes all of the factors into account at the time of the observation, including light pollution, astronomical seeing, altitude in the sky, and the presence of moonlight. These things matter.
There are over a hundred pre-made observing lists available for SkyTools that have been created by leading observers from around the world. Once loaded into the planner, it is a simple matter to filter down to those objects that you can expect to see.
The Nightly Observing List Generator is an awesome tool for finding little-known objects. It can generate a custom observing list of lesser-known objects that you can expect to see with your telescope on any given night.
For all but the brightest objects, it is critically important to observe on the right night, and at the right time in order to get the best view. This is when you have the best chance of seeing more than a blur. The SkyTools planner uses sophisticated models and algorithms to give you the best view possible. Don't be fooled by similar-sounding but much less sophisticated apps.
For star hoppers, the unique three-view finder charts customized for you make it simple to locate any object, even if not obvious in the eyepiece.
For faint objects in large-aperture telescopes it is essential that there are enough stars plotted on the screen/chart in order to locate the correct field, even when using GOTO. The Pro Edition of SkyTools has stars down to 20th magnitude for this purpose.

Greg Crinklaw — Developer of SkyTools

Example SkyTools Finder Chart for an 8-inch Telescope with Telrad (pdf)

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