Survey Astronomy

Imagine trying to understand an entire forest by photographing individual trees, or tracking just a few animals. You’d learn about each one, but you’d miss how all the trees and wildlife grow, change, and interact together. A big-picture view requires you to step back and watch how the forest ecosystem behaves as a single community. That's what an astronomical survey does — but instead of trees or birds, scientists watch the night sky.

An astronomical survey is a systematic way of observing the sky. Instead of pointing a telescope at one target at a time, a survey scans a defined area of sky in a particular pattern to collect observations about everything in view.

Just like you’d photograph your forest differently depending on what you want to learn — like identifying species or tracking changes through the seasons — scientists design astronomical surveys for specific goals. Some surveys scan the whole sky but with less depth, while others might focus on smaller patches to spot extremely faint galaxies. Some surveys prioritize studying the static sky, collecting and stacking many images to reveal faint details, while others prioritize collecting repeated images at regular intervals to track how things change or move.

Rubin Observatory’s Legacy Survey of Space and Time will balance several priorities and blend all of these strategies, covering the entire visible sky every few nights for 10 years. Rubin is designed to make a cosmic time-lapse movie, capturing changes in the cosmos, while also mapping incredibly faint objects. Over the next decade, Rubin will create the most detailed map of the southern hemisphere sky ever made.

Explore more

• Try your hand at surveying the night sky with our online game, Space Surveyors

• Read more about the Legacy Survey of Space and Time (LSST)

• Learn more about Rubin and its survey telescope with this slideshow