A worked example
3.76 µm pixels at 500 mm give about 1.551 arcsec/pixel. A 3 arcsec FWHM spans about 1.934 pixels.
Pixel scale
Convert pixel size and focal length to arcseconds per pixel, with binning and a user-entered seeing value.
YOUR LITTLE WORKBENCH
Pixel scale
Start with an example and change it to your setup. Results update as you type.
Calculation method+
Scale ≈ 206.264806 × pixel size in µm × binning ÷ effective focal length in mm.
YOUR LIVE RESULT ✦
Angular image scale
1.5511 arcsec/px- Pixels across seeing FWHM
- 1.9341 px
- Effective pixel size
- 3.76 µm
- Effective focal length
- 500 mm
This uses the small-angle approximation. Binning is modeled geometrically, without assuming any particular camera readout or sensitivity benefit.
THE METHOD / 01
Know what goesinto your result.
Scale ≈ 206.264806 × pixel size in µm × binning ÷ effective focal length in mm.
Keep the assumptions clear
This uses the small-angle approximation. Binning is modeled geometrically, without assuming any particular camera readout or sensitivity benefit.
A FEW USEFUL ANSWERS
Good to know.
Are my inputs uploaded?
No. Calculations run locally in your browser. The host still receives normal requests for website pages and assets.
Can I keep my result?
Use the download controls for the current tool or print from your browser. Typing scores and camping plans can also be saved locally; see the privacy page for details.
Do I need an account?
No sign-up, paid API or subscription is required. Both language versions use the same calculation logic.
SKYKIND / TOOLKIT
A little help for every step.
01
Magnification
Calculate magnification, exit pupil and effective focal ratio from your optical setup.
Open tool02
Eyepiece fields
Compare two eyepieces on the same telescope with an approximate true-field diagram.
Open tool03
Camera field
Calculate rectangular camera field of view and compare it with an entered angular target size.
Open tool