How do astronomers reduce the effect of twinkling when using telescopes?

In one line

The rule

Twinkling (also called scintillation) is caused by the Earth's atmosphere making starlight bend and shift, which makes stars appear to flicker.

Let's understand it simply

Imagine you are looking at a coin at the bottom of a bucket filled with water. If you shake the bucket, the coin looks like it is moving or wiggling. This happens because the water bends the light. The same thing happens with stars. The Earth's air (atmosphere) is always moving and has different temperatures. This makes the light from stars bend in many directions, so they look like they are twinkling. Telescopes see this twinkling too, which can blur the images.

How it works

1. Astronomers place telescopes on high mountains, where the air is thinner and steadier.
2. They use adaptive optics (a system that changes the shape of a mirror in the telescope very quickly) to correct for the bending of light.
3. Some telescopes are put in space (like the Hubble Space Telescope), where there is no atmosphere, so there is no twinkling at all.
4. Sometimes, astronomers use computer software to process and sharpen the images after taking them.

The story behind it

For many years, astronomers struggled with blurry images because of the atmosphere. In the 1990s, scientists developed adaptive optics to fix this problem. The Hubble Space Telescope, launched in 1990, gave clear pictures because it was above the atmosphere. This showed how much the atmosphere affects what we see.

Where you see it in real life

• Twinkling stars: When you look up at the night sky, stars seem to flicker, but planets do not twinkle as much.
• Mountain observatories: The Indian Astronomical Observatory in Ladakh is built on a high mountain to avoid thick, moving air.
• Space telescopes: The Hubble Space Telescope gives sharp images because it is above the atmosphere.
• Adaptive optics in big telescopes: The Very Large Telescope in Chile uses adaptive optics to get clear pictures.

Why it matters

• Clearer images help astronomers study stars, planets, and galaxies in detail.
• It allows scientists to discover new planets and understand the universe better.
• Reducing twinkling helps in taking accurate measurements of star positions and brightness.
• It is important for space missions and satellite tracking.

Common mistakes

• Thinking twinkling is caused by the telescope itself. (It is caused by the air above us.)
• Believing all telescopes see twinkling. (Space telescopes do not.)
• Assuming only expensive equipment can reduce twinkling. (Location and simple tricks also help.)

Remember it

Twinkling is fixed by going above, around, or correcting the air — high up, in space, or with smart mirrors.