Introductory Astronomy: 

Comets

Comet Ikeya-Zhang. Alaska 2002.

NEAT (Q4) 2004 May 12

Machholz, 2005 January. Note the obtuse angle the dust tails takes (due to perspective), and the spectacular Pleiades star cluster.

Comet Halley Nucleus & jets. Image by the ESA's Giotto mission, 13 March 1986, close approach 596 km.

Comet McNaught, January 2007