In 2010, Comet 103P/Hartley, otherwise known as Comet Hartley 2, visited the inner solar system and put in a favorable appearance, becoming barely visible to the unaided eye. In this view, we see it giving off the characteristic green color that many dim comets exhibit, in the constellation Perseus, between the upper tip of the outline and and Double Cluster at the top of the image. Unannotated image.
Mouse over the above thumbnail to see an enlarged view of the comet amongst the stars of northwestern Perseus. My camera has an ASP-C sensor and I used a 230 mm lens which, when expanded to the size of an image made with a full frame camera, is equivalent to using a 345 mm lens.
The path of the comet through the sky points to the bottom of the image; it will head in a southeastern direction from here on out. Previously, Hartley crossed over Cassiopeia; from here it will continue through Perseus, after which it will pass very close to the star Capella in Auriga on 19 October, although by then the full Moon spoils the view.