Telescope Resolving Power Calculator
Resolving power is the smallest angle a telescope can separate, which decides whether a tight double star shows as two points or one blurred blob. It depends almost entirely on aperture: bigger mirrors and lenses resolve finer detail. This calculator gives two classic figures in arcseconds. The Dawes limit, 116 divided by the aperture in millimeters, is an empirical rule for splitting equal magnitude double stars. The Rayleigh limit, 138 divided by the aperture in millimeters, is the stricter physical diffraction criterion. Enter your aperture to see both, along with the useful magnification you need to actually perceive that separation. All math runs locally in your browser with nothing uploaded.
How to use Telescope Resolving Power Calculator
- Enter your telescope aperture in millimeters or inches.
- Read the Dawes and Rayleigh limits in arcseconds.
- Compare a double star separation against the limit to judge if your scope can split it.
Frequently asked questions
What is the difference between the Dawes and Rayleigh limits?
Both give the finest angle in arcseconds a scope can separate, but Dawes is the empirical tighter split for equal stars while Rayleigh is the slightly larger theoretical diffraction limit.
How does aperture set my resolving power?
Resolution improves as aperture grows; the Dawes limit is about 116 divided by aperture in millimeters, so a bigger scope splits closer double stars.
Does resolving power depend on magnification?
No; the theoretical limit is fixed by aperture and the light wavelength, though you still need enough magnification and steady seeing to actually see the split.
What is Telescope Resolving Power Calculator?
Resolving power is the smallest angle a telescope can separate, which decides whether a tight double star shows as two points or one blurred blob. It depends almost entirely on aperture: bigger mirrors and lenses resolve finer detail.
Is Telescope Resolving Power Calculator free to use?
Yes. Telescope Resolving Power Calculator is completely free, with no sign-up and no usage limits.
Does Telescope Resolving Power Calculator work in a web browser?
Yes. Telescope Resolving Power Calculator runs in any modern web browser. There is nothing to download or install.
Is my data private with Telescope Resolving Power Calculator?
Yes. Telescope Resolving Power Calculator runs entirely on your device in your browser, so nothing you enter is uploaded to a server.
Badge
Link this tool from a README, doc or site. The badge links back to this page.
[](https://yourhack.ai/telescope-resolving-power-calculator)