---
type: Concept
title: Astronomical Seeing
description: The blurring of star images caused by atmospheric turbulence, measured
  in arcseconds where a lower value means a sharper image.
aliases:
- seeing
tags:
- astronomy
- atmospheric-optics
- observing-conditions
resource: raw/figure-brief.pdf
timestamp: '2026-07-16T15:11:30Z'
citadel_version: 0.3.0
---

Seeing is the blurring of stars' images caused by atmospheric turbulence.[^s1] It is reported in arcseconds, and a lower value means a sharper image.[^s1]

At [Cinder Peak Observatory](../organizations/cinder-peak-observatory.md), median nightly seeing is tracked and reported as monthly medians; through 2025, the autumn months were consistently the sharpest of the year.[^s2] The single best nightly median of the year was 0.42 arcsec, recorded on November 14.[^s3]

## See also
- [Cinder Peak Observatory](../organizations/cinder-peak-observatory.md)

## Sources
[^s1]: [raw/figure-brief.pdf](../../raw/figure-brief.pdf), p. 1 — seeing defined as atmospheric-turbulence blurring of stars, reported in arcseconds, lower is sharper (ingested 2026-07-16)
[^s2]: [raw/figure-brief.pdf](../../raw/figure-brief.pdf), p. 1 — autumn nights consistently the sharpest of the year (ingested 2026-07-16)
[^s3]: [raw/figure-brief.pdf](../../raw/figure-brief.pdf), p. 1 — Figure 1 bar chart: best single-night median of 0.42 arcsec recorded Nov 14 (ingested 2026-07-16)
