Curved images on a photographic plate that record the changing positions of stars when a telescope is not driven so as to keep up with their diurnal motion. Even if such a drive is being used, comet trails will still be recorded.
The addition of a tripod and some form of shutter-release cable to your equipment will not only make framing your composition easier, it will open up a new possibility for your imaging: star trails. Star trails show the stars arcing across the sky as the Earth rotates.
Delhi becomes a good location for star trails in clear weather in the postmonsoon months." The astrophotographers' works will also be on display in few other cities as part of the festival which has been organised by Institut Francais en Inde, the French Embassy and the Alliance Francaise in India.