On this page of the guide to BioShock Infinite, you will find basic information about Kinetoscopes and Telescopes. Such objects can be found in Vantage Points and the game considers them as secrets / collectibles.
The following chapter contains a complete list of Kinetoscopes and Telescopes scattered throughout the entire Columbia. Much like Voxophones, vantage points often offer additional information about the city and how it was built. The telescopes can also help you in discovering things you wouldn't normally see. Finding all vantage points is needed to unlock the Sightseer achievement/trophy.
Important: If you missed a telescope or a kinetoscope, you don't need to restart the whole game. You can repeat specific chapters - the option is available in the main menu of the game.
It is worth mentioning that not all chapters feature this type of collectibles. If a chapter isn't present in this guide, then it doesn't feature any kinetoscopes or telescopes.