3.76 µm pixels at 480 mm
206.264806 × 3.76 / 480 = approximately 1.6157 arcsec/pixel. One pixel represents this angle; the number does not establish sharpness.
Load this example in the calculatorPixel-scale calculator
Convert camera pixel pitch and telescope effective focal length to angular image scale in arcseconds per pixel.
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What this calculation tells you
Pixel scale describes the angular size represented by one pixel near the optical axis. It is a conversion between camera geometry and sky angle, not a measurement of the resolution your full imaging system actually delivers.
Inputs and workflow
- Enter effective focal length in millimetres, accounting for the optical configuration.
- Enter physical pixel pitch in micrometres. Do not enter total sensor width or megapixels.
- Use the output in arcseconds per pixel when comparing seeing, guiding measurements or image sampling. If using binning, use the effective pixel pitch for that comparison.
Formula and units
Scale (arcsec/pixel) ≈ 206.264806 × pixel pitch (µm) / focal length (mm). The factor converts radians to arcseconds and micrometres to millimetres.
Worked examples
Same pixels at 960 mm
The scale is approximately 0.8079 arcsec/pixel. Doubling focal length halves the angular size per pixel, without promising twice the resolved detail.
Load this example in the calculatorLimits before using the result
This is the small-angle plate-scale approximation near the axis. It does not model distortion or field-dependent image scale.
Seeing, focus, diffraction, tracking and processing can limit actual detail. There is no universal best arcsec/pixel threshold in this calculator; use the separate sampling tool for an explicit FWHM comparison.
Sources and method notes
- Atik: image-scale calculation
Source for the pixel-size/focal-length conversion. Its ideal-scale purchasing thresholds are not adopted here.
Calculation notes maintained by AstroGearFit. Updated September 7, 2026. Examples are numerical demonstrations, not hands-on equipment tests. The method notes are currently in English; the existing interface language selector remains available.
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