Guide to Launch Activities

Our Launch activities are designed to enable introductory-level students to get started navigating the SDSS database and to set out on explorations of the Solar System and the Milky Way.

The Launch section itself is structured to support the development of an accurate mental model of the Universe. The activities are grouped in order of distance from Earth, and each involves the discovery of an astronomy or engineering concept using SDSS data.

Clip art of a rocket launching
Earth from space

Launch into the SDSS

We begin our voyages here on Earth, exploring the SDSS itself. This section enables students to explore the SDSS telescope, its associated instruments, and how data are stored and retrieved.

What is the SkyServer?

The concept of a database and how one can be organized and accessed is an important topic for today’s students to understand. This activity invites students to think critically about how data are stored and accessed by computers.

Students are guided through a sequence that demonstrates how SDSS images are recorded, stored, retrieved and displayed in the SkyServer. By inviting students to navigate through beautiful and interesting images of the sky, this activity begins the process of building an intuitive bridge from student experience to the SDSS database.

Consider doing this activity in conjunction with Launch – Constellations in SDSS Data to get students looking up at the sky before diving into the data.

My Special Place in the SDSS Database

This activity teaches students to use tables and a star finder to locate a unique place within the SDSS database that can act as a starting point for many different activities in Voyages. Students can relate an area of the sky they are familiar with to how it appears in SkyServer, thus building a sense of the magnification and detail of the SDSS images.

The SDSS database contains hundreds of millions of objects, and students may enjoy picking their own corner of the sky to explore. This activity starts uses familiar bright stars as anchors for individualized explorations.  Students are invited to develop an in-depth understanding of their own unique part of the sky.

Consider printing a copy of the start wheel included in this activity and teaching students how to use it in advance. Consider holding a star party. This will ground students’ abstract explorations in personal experience.

Scavenger Hunt

The SkyServer makes it easy to scroll through the SDSS imaging data and explore the full zoo of objects therein.  This activity begins by providing students with a field guide for recognizing stars, galaxies, asteroids, and more.  With this knowledge in hand, students are set free to search for examples on their own in the vast SDSS dataset. For more information, see our teacher notes.

Old Time Astronomy

Learn what astronomy was like long ago, before the invention of the camera. For more information, see our teacher notes.

An illustration of a planet passing in front of a star

Launch into the Solar System

Activities in this section explore objects found within our own solar system, such as asteroids and planets.


In the process of capturing images of stars, galaxies, quasars, the SDSS detected many objects in our own cosmic backyard. In addition to the occasional comet or meteor, the SDSS database contains 10,000 asteroids. This activity provides and introduction to the topic of asteroids and how to find them in SDSS images. For more information, see our teacher notes.

An artist's impression of the central region of a galaxy

Launch into the Milky Way

Almost all of the stars in the SDSS database reside within our own galaxy, the Milky Way. These activities use SDSS data to explore the concepts of constellations and star color.

Constellations in SDSS Data

This activity starts with the idea of naked-eye constellations and leads students to discover their own “constellations” in SDSS imaging and plates.  Key concepts covered in this activity include apparent brightness, sky coordinates, and magnification.

Star Color

This activity has students begin with the naked-eye observation of star color to build an understanding of both the magnitude scale and color as quantitative measurements in astronomy. Students also start building an understanding of how magnitudes in different filters can be combined to measure “color” in different ways.  Preflight – Filters can be a useful resource for this activity.

If your students are new to the magnitude scale in astronomy, try jumping directly into this activity without discussing the scale in advance. For most students, uncovering the inverse nature of the scale for themselves can be more helpful than being told about it.  If a subset of your class is frustrated by this approach, you can determine the best time to provide some supportive clues. You could have cards at the ready with helpful hints or the link to Preflight – Magnitudes.

Launch into the Universe

Almost all of the stars in the SDSS database reside within our own galaxy, the Milky Way. These activities use SDSS data to explore the concepts of galaxies, redshift, and gravitational lensing.


This activity lets students find spectral lines and measure redshifts of SDSS galaxies to learn how we know how far away galaxies are, and to introduce the idea of the expanding universe.

Gravitational Lensing

This activity introduces students to the concept of gravitational lensing, and how it can be used to understand our universe.