Telescope-Simulator is an online focal length calculator that shows a simulated view of how eyepieces and telescopes would see Mars, Jupiter, Saturn, the Moon and the Pleaides.

Select a simulator: Telescope Calculator or Telescope Comparison

All previews assume viewing at prime focus. Current angular size of planets may vary.

Telescope Calculator Telescope Comparison
Telescope Eyepiece Calculator Telescope Eyepiece Comparison

Telescope Calculator and Telescope Comparison show realistic proportioned views of what you will see with different telescopes and eyepieces. The simulated true feld of view and several readouts automatically refresh as you change the settings. This software has been used by people all over the planet to learn about telescopes, eyepieces and the inter-relationship of focal length, aperture and many other terms used to describe the telescopes and eyepieces. This program does not simulate lens quality or seeing conditions.

Within the program, the following telescope calculations are updated in a real time display view: telescope magnification, effective focal length, telescope focal ratio, eyepiece exit pupil size, true field of view, and eyepiece field stop. The simulated views quickly illustrates how telescopes and eyepieces work to create a telescopic view.

Telescope Calculator enables the following settings to be adjusted: telescope focal length, telescope aperture, eyepiece focal length, eyepiece apparent field of view, barlow settings, and celestial object to be viewed (Full Moon, Half Moon, Mars, Jupiter, Saturn, Pleiades).


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