`\alpha = 2.06 \times 10^5 ( \lambda / D )`

0.3777

The Resolving Power of a Telescope calculator computes the angular distance between two stars on the limit of visibility for a telescope.

INSTRUCTIONS: Choose units and enter the following:

• (λ)  Wavelength of light
• (D) Diameter of Telescope

Resolving Power (α): The calculator returns the Resolving Power in  arc seconds.  

The Math / Science

The resolving power of a telescope is the angular distance between two stars that are just barely visible through the telescope as separate images. The resolving power α in arc seconds of a telescope with diameter D in meters that is collecting light of wavelength λ in nanometers equals is given by this formula.  The formula for the resolving power of a telescope is:

     `α = 2.06 x 10^5 ( λ / D )`

where:

• α = resolving power
• λ = wavelength of light
• D = diameter of telescope

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Astronomy Calculators

The Astronomy Calculator Suite includes functions that are useful for studying astronomy and include the following:

• Kepler's 3^rd Law formula                             T² = (4π • R³)/(G • M)
  • (M) - mass of the system. 
  • (T) - period of the orbit.
  • (R) - separation distance between the two objects.
  • (G) - universal gravity constant
• Small Angle Formula        Small Angle Formula    α = S / D
  • (α) - angle
  • (D) - distance to astronomical object
  • (S) - size or diameter of astronomical object
• Flux and Magnitude formulas
  • Change in Magnitude from Flux Ratio
  • Flux Ratio from Magnitudes
• Telescope formulas
  • Resolving Power of a Telescope
  • Magnification of a Telescope
• Mass formulas
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  • Mass from Acceleration and Radius
  • Mass from Speed and Separation
  • Mass of extra-solar planet from mass of star, radius of star orbit and radius of exoplanet orbit
  • Mass of extra-solar planet from mass and velocity of star and velocity of planet
  • Black Hole Mass Calculator
  • Black Hole Event Horizon Calculator
• Relative Size Formulas
  • Relative Size from Relative Temperature and Luminosity
  • Relative Temperature from Relative Size and Luminosity
  • Relative Luminosity from Relative Temperature and Size
• Wavelength Formulas
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  • Wavelength Shift from Wavelength and Speed
  • Blackbody Wavelength from Temperature
  • Blackbody Temperature from Peak Wavelength
  • Photon Energy from Wavelength
  • Photon Wavelength from Energy
• Other Formulas
  • Distance from absolute and apparent magnitude
  • Radius from Speed and Period
  • Speed of Circular Motion
  • Hubble Time
  • Galaxy Recession Velocity
  • Luminosity from Mass
  • Hubble's Law
  • Exoplanet Calculator 
  • Orbital Radial Acceleration
  • Distance to Barycenter
  • Sakuma-Hattori Equation
  • Astronomical Distance Calculator provides the distance from the Earth to numerous astronomical bodies (e.g. Sun, Moon, planets, stars, Milky Way's Center and Edge, Andromeda Galaxy)
  • Astronomical Distance Travel Time Calculator computes the time to travel to distant parts of space at different velocities.
  • 3D Vector Calculator
  • Drake Equation Calculator
  • Seager Equation Calculator
  • Friedman Equation Calculator
  • Lagrange Points L1 and L2
  • Schwarzschild Radius
  • Hill Sphere Radius
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