What Is "Seeing" in Astrophotography? The Science Behind Atmospheric Turbulence

Summary

Table of ContentsWhat is Astronomical Seeing?How Does Seeing Affect Your Images?My First Experience with Bad SeeingHow to Measure Seeing ConditionsWhen is Seeing at Its Best?Tools to Check Seeing ConditionsTips for Dealing with Poor SeeingSeeing vs Transparency: What’s the Difference?How to Improve Your Results Despite Poor SeeingConclusion: Working with What You’ve GotReferencesThe night sky was crystal clear, stars shimmering gently. I had my telescope perfectly aligned, camera settings optimized, and target acquired—Jupiter, in all its glory. But when I reviewed my images later, instead of the sharp, detailed gas giant I expected, I found only a blurry, wobbling mess. What went wrong? The culprit wasn’t my equipment or technique—it was something far more fundamental that many beginning astrophotographers overlook: atmospheric seeing conditions. Understanding this single factor could be the difference between frustrating failures and breathtaking cosmic portraits. Here’s what five years of stargazing have taught me about working with (and sometimes against) our turbulent atmosphere.To understand why my Jupiter photos failed that night, we first need to answer this question: what does seeing mean in astrophotography?What is Astronomical Seeing?Astronomical seeing refers to the quality and stability of Earth’s atmosphere and how it affects the sharpness of celestial objects when viewed or photographed through a telescope. Poor seeing makes stars appear to twinkle and blurs objects, while good seeing allows for sharp, steady views.While this definition explains the basics, the reality of how our atmosphere interferes with starlight is far more complex than most people realize.Diagram showing how disturbances in the atmosphere affect astronomical imagesLet’s look more closely at how Earth’s atmosphere affects how we see objects in space from the ground. Most people think of air as empty space, but that is far from the truth. If this were true, then aeroplanes wouldn’t...