---
title: "Color & Wavelength in Astrophotography"
canonical: https://stackingstarlight.com/start-here/color-and-wavelength
description: "Wavelength determines color, from ~400nm violet to ~700nm red. Nebulae emit at specific lines like Hα (656nm), OIII (501nm), and SII (672nm)."
---

# Color & Wavelength in Astrophotography

> Wavelength determines color, from ~400nm violet to ~700nm red. Nebulae emit at specific lines like Hα (656nm), OIII (501nm), and SII (672nm).

Visible light spans roughly 400nm (violet) to 700nm (red). Stars emit a continuous spectrum, but nebulae glow at discrete **emission lines** set by their chemistry: hydrogen-alpha (Hα, 656nm, deep red), doubly-ionized oxygen (OIII, 501nm, teal), and singly-ionized sulfur (SII, 672nm, red). Because these lines are narrow and specific, you can isolate them with narrowband filters — capturing nebula light while rejecting almost all light pollution. This is also the basis of false-color palettes like SHO (the Hubble palette).

---

Source: [https://stackingstarlight.com/start-here/color-and-wavelength](https://stackingstarlight.com/start-here/color-and-wavelength) · Part of [Stacking Starlight](https://stackingstarlight.com) by Michael Kalika.

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