objects observed have tended to have specific characteristics that attracted attention to them, and with very bright optical and/or X-ray emission in particular. They are not ‘typical’ SNRs, and so the picture we derive for the global impact of SNRs on their host galaxy is seriously biased.

Positions for FUV spectral observations have often been selected based on the optical appearances or characteristics of the region or object being observed, including not only the surface brightness but also particular line ratios or signatures (e.g., Raymond et al. 1988; Blair et al. 2002; and references therein). More recently, a few FUV observation positions have been selected based on the appearance in soft X-rays rather than optical (Raymond et al. 1997; Sankrit et al. 2001). With very few FUV images available for guidance, observers have had little else to go by.

However, there have been a growing number of indications that selection criteria for FUV observations of SNRs have been too narrow. FUV spectro-imaging of the Cygnus Loop and Vela SNRs from the Voyager Ultraviolet Spectrometers (Blair et al. 1991, 1995) and of Vela recently by the SPEAR experiment (Nishikida et al. 2006) show patchy, variable spatial distributions in key FUV emission 