A telescope is a device used to view far away objects.
The Sniper Rifle/Sextant was missing a telescope, meaning it was useless in both forms. FPI created a candy telescope, but it was useless even with the most concentrated ogle because it was made of candy. A useful telescope, the Chronoscope of Axial Conjugation, appeared from the Cathedral of Syndetic Ascension as the Clock Tower of Cartesian Alignment struck 12 o'clock. By pulling the Chronoscope out of the cathedral through the wheel of the Chicago Overcoat, the wheel was deactivated. PI used the Chronoscope with his Sniper Rifle to fight Dark Matter Mobster Kingpin. The Chronoscope was later used again with the Sextant to help PI navigate.
John Egbert has a telescope on his balcony. He used this telescope to look at the meteor which was heading towards his house due to Sburb. Later, he alchemized the telescope with his Sledgehammer and his copy of Colonel Sassacre's to create the Telescopic Sassacrusher.