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For Students · Telescope Optics

Telescope Optics for a star's life

Built for students learning it for a class or exam. See the concept move instead of memorizing formulas — and check your homework intuition. Simulate a star's life live below — adjust the inputs and watch it respond, right in your browser.

Telescope OpticsLive

resolution · magnification · light grasp

Controls

Presets

Aperture (mm)

Objective focal length (mm)

Eyepiece focal length (mm)

Wavelength (nm)

Aperture rules everything: resolving power is θ = 1.22·λ/D (Rayleigh criterion), light-gathering scales as D², and the faintest visible star climbs with aperture. Magnification is just objective focal length divided by eyepiece focal length — and is useless beyond what the aperture can resolve.

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Data Inspector

Resolution0.69″

Magnification120×

Light vs eye816×

Limiting mag14.2

Governing equation

M = \frac{f _{o}}{f _{e}} = 120 \times, θ = \frac{1.22 λ}{D} = 0.6 9^{''}, grasp \propto D^{2}

Reading this result: Well matched: 120× sits under the 400× ceiling, so the 0.69″ resolving power of this aperture actually shows real detail.

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Frequently asked questions

Is this good for students?: Yes — this version of "Telescope Optics for a star's life" is framed for students learning it for a class or exam. See the concept move instead of memorizing formulas — and check your homework intuition.
Do I need to install anything?: No. It runs in any modern browser, free, with no account required.