The angular resolution and sensitivity of NGSS allows detailed study of the internal structure of galaxies in the local Universe, whose properties provide our basic, analog understanding of high-redshift galaxies. For a 20 Mpc galaxy, the spatial resolution is 1 kpc at 23 microns and 0.5 kpc at the shorter wavelength bands. Owing to the all sky coverage, this sample will include over 5000 galaxies (within 20 Mpc of the Sun) ranging across the Hubble morphology sequence. Of this set, nearly ~400 galaxies will be highly resolved, delineating globular clusters, giant molecular clouds and other discrete sites of star formation. The short mid-infrared bands of NGSS are an effective probe of the underlying stellar population and are fairly immune to extinction. The long bands are sensitive to hot dust associated with star formation; and thus the NGSS bands bridge the time span between evolving generations of stars. The NGSS survey of nearby galaxies will form a complimentery dataset to the SIRTF Nearby Galaxy Survey Legacy project, expanding their sample of 75 galaxies to many thousands of galaxies, covering the widest range in morphological type. NGSS will provide the crucial mid-IR information of the SED for large sample multi-wavelength galaxy surveys (e.g., 2MASS). The composite near-to-mid infrared image of the Whirlpool Galaxy (M51) illustrates the power of combining multi-wavelength data. The M51 system is comprised of an early-type interloper (M51b) and a late-type spiral (M51a) whose underlying older stellar population is traced by the 2MASS J and Ks bands (blue & green tones), and the sites of star-formation (via hot dust, PAH and HII emission) are revealed in the mid-infrared 6.7 micron ISOCAM image (red tones).

• see also the 2mass/iso combined mosaic of M83
  blue = 2MASS J (1.2 microns)
  green = 2MASS Ks (2.2 microns)
  red = ISOCAM LW2 (5.5 - 8.5 microns)
  

• see also the unabridged version(s).