Assertion: telescope's length | /r/HasProperty | focal
Facets:
value: long
type: DEGREE
Source sentences:
text: Often accessory lenses, such as focal reducers and field flatteners, are used with these fast, wide field telescopes to flatten their image field and/or reduce their focal length even further.
text: This Newtonian-style reflector telescope comes with a 5-inch aperture and 1,000-millimeter focal length, both of which are a steal for under $150.
text: Here is a list of the largest optical refracting telescopes sorted by lens diameter and focal length.
text: It has a silvered "spot" secondary on the corrector, making a long focal length but compact (folded optical path) telescope with a narrow field of view.
text: Most telescopes list the focal length in the manufacturer specifications.
text: The Telescope features 4.5″ aperture and 900m focal length for perfect, in-depth images of the moon, Jupiter, Saturn, and so on.
text: – having a higher f/ratio means that your telescope has a longer focal length and telescope tube while a lower f/ratio means shorter focal length and telescope tubes.
text: To calculate this, take the focal ratio of the telescope (which is the focal length divided by the aperture) and multiply it by seven.
text: Almost every telescope ever made will have the focal length marked on it, usually near where the eyepiece goes into the scope.
text: Most telescopes list the focal length in the manufacturer specifications.
text: The focal ratio of a telescope is calculated by dividing its focal length by its aperture size.
text: The focal ratio of a telescope is derived from dividing its focal length (how long the telescope is) by the width of its largest optical element (either its lens for a refractor or its primary mirror for a reflector).