R- and J-band photometry of Comets 2P/Encke and 9P/Tempel 1

Near-simultaneous R- and J  -band photometric measurements of the short-period Comets 2P/Encke and the Deep Impact mission target 9P/Tempel 1 were obtained. The resulting R–JR–J colors are +0.82±0.08 mag+0.82±0.08 mag and +1.46±0.13 mag+1.46±0.13 mag for Encke and Tempel 1, respectively. Tempel 1's color is redder than the solar R–JR–J color index of +0.76. The Tempel 1 observations directly detected the nucleus while the Encke observations likely suffered from coma contamination.