NGC 300 is the brightest of the five larger spiral galaxies in the direction of the Sculptor Group of galaxies. Until recently, NGC 300 and NGC 55 (which see, for a chart of their relative positions) were thought to be members of that group, but they are now thought to be foreground galaxies. (The two galaxies are probably gravitationally bound, as they are only a million or so light years apart.) The distance of NGC 300 is estimated at 6 to 8 million light years, giving it a diameter of about 75 thousand light years. It is a relatively diffuse spiral with a poorly defined core, much like M33, in Triangulum. As such, it is an absolutely perfect example of its type. The image immediately below shows the galaxy as it would appear if our eyes were hundreds of times more sensitive to light and color than they are. In that sense, it is a "realistic" image, even though giving a false impression of the actual appearance of the galaxy, as it would be seen by the eye, even through a telescope. (M. Schirmer (IAEF, Bonn), W. Gieren (Univ. de Concepción, Chile), et al., ESO, apod020821)

The image below shows NGC 300 viewed through an Hα filter, so that gaseous regions heated by hot young stars, or shock waves from stellar explosions, stand out; while the visible and ultraviolet radiation of those stars is blocked, making them fade into the background. The image is in black and white, which is actually the way that all professional astronomical images are taken. Colors are added when combining images taken at different wavelengths, to highlight different features. (M. Schirmer (IAEF, Bonn), W. Gieren (Univ. de Concepción, Chile), et al., ESO, apod020822)

The image below is a composite of visible light (colored red and yellow) images and a far UV GALEX image (colored blue), which emphasizes various features by use of the false colors used for the images. The result is that young hot blue stars stand out in the regions where they recently formed, while gases heated by their ultraviolet radiation, and shock waves from stellar explosions appear in pink; and the older stars in the core look yellow-green. This reveals more structural information than a "realistic" color choice, but is a "false-color" image in every sense of the phrase. (JPL-Caltech/OCIW/GALEX, NASA)

the image below is an HST image of the core of NGC 300, in which millions of stars are individually imaged. Studying such images over a period of time should allow the discovery of hundreds of Cepheid variables, and provide a far more accurate estimate of the galaxy's distance than is currently available. (Hubble Heritage Team (AURA / STScI), ESA, NASA, apod050820)

The image below shows all of NGC 300 at upper left, the region imaged in detail (above) at upper right, and a small inset of the core at the bottom, to show just how detailed the HST image really is. (NASA, ESA, and The Hubble Heritage Team (AURA/STScI), HubbleSite)

A starburst galaxy. Based on recessional velocity of 4555 km/sec, about 200 million light years away. Given that and apparent size of 1.2 by 1.0 arcmin, about 70 thousand light years across.

Based on recessional velocity of 5585 km/sec, about 250 million light years away. Given that and apparent size of 0.6 by 0.45 arcmin, about 45 thousand light years across.