The best examples of analyzing star light spectrum: 3 practical examples for students

3 practical examples of analyzing star light spectrum for a science project

Instead of starting with theory, let’s jump straight into real examples of analyzing star light spectrum that you can actually run. Then we’ll unpack the science behind each one.

We’ll build around three main projects:

• Comparing star colors and temperatures using simple spectra
• Identifying stellar elements from absorption lines
• Measuring Doppler shifts to study star motion (using real data)

Along the way, we’ll pull in extra real examples and variations so you can scale the difficulty up or down.

Example 1: Comparing star colors and temperatures from their spectra

This first example of analyzing star light spectrum is perfect if you’re working with basic equipment: a diffraction grating, a tripod, and a camera (even a decent smartphone can work with care).

The basic idea

Stars of different temperatures emit different distributions of light. Hotter stars peak in the blue or ultraviolet; cooler stars peak in the red or infrared. When you spread a star’s light into a spectrum, you can compare how bright it is in different color bands and connect that to surface temperature.

This project gives you one of the best examples of how a simple spectrum can turn a blurry dot of light into measurable physics.

What you do

You aim your setup at several bright stars with different known spectral types, such as:

• Betelgeuse (Orion) – cool red supergiant (M-type)
• Rigel (Orion) – hot blue supergiant (B-type)
• Sirius (Canis Major) – bright A-type star
• Vega (Lyra) – A-type, often used as a calibration reference
• The Sun – via indirect reflection off a white card at sunset for safety

You record short exposures of each star’s spectrum. Then you measure the intensity of the spectrum in different color regions (for instance, red, green, blue bands) using free software like ImageJ or Tracker.

How to connect to real astrophysics

Once you have intensity vs. wavelength, you can:

• Estimate which color band is strongest for each star.
• Compare your results to published temperatures and spectral types from professional catalogs such as the SIMBAD Astronomical Database or data summarized by NASA.
• Plot a simple version of a color–temperature or color–magnitude relationship.

This gives you one of the simplest real examples of analyzing star light spectrum: turning color differences into temperature estimates. It echoes the same physics behind Planck’s law and Wien’s displacement law, although you don’t need to compute full blackbody curves unless you want an advanced extension.

Possible extensions

If you want to push this project further:

• Add more stars and sort them by spectral class (O, B, A, F, G, K, M).
• Compare your measured color ratios with published color indices (like B–V) from databases such as the European Space Agency’s Gaia mission.
• Investigate whether interstellar dust (for stars near the Milky Way plane) seems to redden spectra compared with stars high above the galactic plane.

These variations give you additional examples of analyzing star light spectrum while still using the same basic setup.

Example 2: Identifying stellar elements from absorption lines

If you’re ready for something a bit more technical, this second example of analyzing star light spectrum focuses on the dark lines that slice through a star’s rainbow: absorption lines. Those lines are fingerprints of specific elements in the star’s atmosphere.

Even with modest equipment, you can see the strongest lines in bright stars and compare them with laboratory data.

The basic idea

Every element absorbs light at very particular wavelengths. Hydrogen, helium, sodium, calcium, and iron all leave distinctive patterns of dark lines in a star’s spectrum. This is how astronomers first figured out that stars are mostly hydrogen and helium.

In this project, you capture higher-resolution spectra of a few bright stars and then match their absorption lines to known atomic transitions.

Targets and spectral features

Good targets and lines include:

• The Sun (via reflection): Strong hydrogen Balmer lines (Hα at 656.3 nm, Hβ at 486.1 nm), calcium H & K lines (around 396.8 and 393.4 nm), and many iron lines.
• Sirius: Very strong hydrogen Balmer lines typical of A-type stars.
• Capella: Cooler G-type giant, with more prominent metal lines compared to hot stars.
• Arcturus: K-type giant with rich metal lines and weaker hydrogen lines.

You record spectra with a grating spectroscope or a low-cost Star Analyser grating mounted in front of a camera. Then you calibrate the wavelength scale using known emission lines from a calibration source (for example, a compact fluorescent lamp or a low-pressure gas tube if your school lab has them).

Matching lines to elements

Once you have a calibrated spectrum, you:

• Identify dark lines visually.
• Measure their pixel positions.
• Convert those positions to wavelengths using your calibration.
• Compare your measured wavelengths with published atomic line tables.

Good references for line data include:

• The NIST Atomic Spectra Database (National Institute of Standards and Technology, nist.gov)
• University astronomy lab manuals from sites like Harvard University’s astronomy labs

This is one of the best examples of analyzing star light spectrum if you want to show chemistry and physics working together. Your conclusion can literally list which elements you detected in each star.

Modern angle: 2024–2025 trends

In professional astronomy, this kind of analysis has exploded in scale. Projects like APOGEE and GALAH are measuring detailed spectra for hundreds of thousands of stars to map the Milky Way’s chemical history. You can reference recent survey work from:

• Sloan Digital Sky Survey (SDSS)

Your science fair project becomes a small-scale version of what these large surveys do: identify elements from absorption lines to infer how stars formed and evolved.

Example 3: Measuring Doppler shifts and star motion using real data

The third of our 3 practical examples of analyzing star light spectrum takes you into the territory of radial velocity—how fast a star is moving toward or away from us. This is much harder to do with school-level equipment, but you can absolutely do it using publicly available professional data.

The basic idea

When a star moves toward us, its spectral lines shift slightly toward shorter wavelengths (bluer). When it moves away, lines shift to longer wavelengths (redder). The amount of this Doppler shift tells you the star’s radial velocity.

Instead of trying to measure this directly with a backyard setup, you download spectra from an online archive that already includes high-resolution data.

Where to get spectra

Good sources of real examples of stellar spectra include:

• NOIRLab Data Lab – U.S. national optical–infrared astronomy lab with public data.
• ESO Science Archive – European Southern Observatory’s database of high-resolution spectra.
• SDSS SkyServer – Spectrum browser with tools to view and download star spectra.

These archives often include radial velocity measurements, but for a strong project you should show how you could estimate that velocity yourself.

How to measure the shift

You pick a well-known absorption line, such as the Hα line at 656.3 nm or a prominent calcium line, and:

• Note the rest wavelength from a reference table (for example, from the NIST database).
• Measure the observed wavelength in your downloaded spectrum.

• Use the Doppler formula:

  \[ v = c \times \frac{\lambda_{observed} - \lambda_{rest}}{\lambda_{rest}} \]

  where \( v \) is radial velocity and \( c \) is the speed of light.

You can do this in a spreadsheet or a short Python script. This is a clean, quantitative example of analyzing star light spectrum that leads directly to a numerical result you can graph and compare.

Going further: exoplanets and binary stars

If you’re ambitious, look for spectra of:

• Spectroscopic binary stars, where two stars orbit each other and their spectral lines shift back and forth over time.
• Stars with known exoplanets, where tiny periodic shifts in spectral lines reveal the planet’s gravitational tug.

You probably won’t discover a new planet, but you can reproduce the logic that professional exoplanet hunters use. That’s one of the most exciting real examples of analyzing star light spectrum in modern astronomy.

More real examples and variations using star light spectra

Beyond the main 3 practical examples, there are several side projects that still count as strong examples of analyzing star light spectrum for a science fair or classroom setting.

Comparing star spectra to LED and gas discharge lamps

A clever variation is to compare stellar absorption spectra with emission spectra from:

• Neon signs
• Sodium vapor streetlights
• Compact fluorescent bulbs
• LED flashlights of different colors

You record spectra of these artificial light sources and show how their bright emission lines match the dark absorption lines in star spectra. This is an excellent bridge between classroom physics and astrophysics and gives another example of how the same atomic physics appears in both lab and sky.

Tracking atmospheric effects on spectra

You can also study how Earth’s atmosphere affects spectra by capturing the same star at different altitudes in the sky.

For example:

• Record Vega near the horizon and again when it’s high overhead.
• Compare how the blue end of the spectrum is dimmed when the light passes through more atmosphere.

This is a neat example of analyzing star light spectrum to show atmospheric scattering and absorption. It connects directly to how professional observatories choose high, dry sites and why space telescopes like Hubble and James Webb avoid atmospheric distortion entirely.

Using star light spectra to estimate interstellar dust

For advanced students, a project can focus on how dust between stars reddens their light. You:

• Select stars of the same spectral type but at different distances.
• Use published spectra or photometric data from sources such as Gaia or SDSS.
• Compare how much their color indices differ from what you’d expect.

This gives you another data-driven example of analyzing star light spectrum to infer something invisible—dust spread through the galaxy.

How to frame your project for judges and teachers

When you present these examples of analyzing star light spectrum, the strongest projects do three things:

• Explain the physics clearly. Show how color relates to temperature, lines relate to elements, and shifts relate to motion.
• Show your method. Include how you calibrated wavelengths, how you measured intensities, and what software or data sources you used.
• Compare with professional data. For instance, match your temperature estimates with values from NASA or your measured line wavelengths with NIST tables.

Judges love to see that your work connects to how real astronomers operate in 2024–2025, especially if you reference current surveys and missions.

FAQ: common questions about examples of analyzing star light spectrum

What are some easy examples of analyzing star light spectrum for beginners?

Good starter examples include comparing the spectra of a few bright stars with different colors, or recording the Sun’s spectrum (safely, via reflection) and identifying just one or two major absorption lines like hydrogen Hα or the sodium doublet. You can do both with a simple diffraction grating and a camera.

Can I do an example of star light spectrum analysis without a telescope?

Yes. Many students get good results using only a diffraction grating and a tripod-mounted camera aimed at bright stars or planets. For more advanced analysis, you can skip equipment entirely and use professional spectra from online archives such as SDSS or NOIRLab.

How accurate are student projects that analyze star light spectra?

Your measurements won’t match professional observatories, but they can still be surprisingly good. With careful calibration, you can identify major elements, estimate temperatures within a reasonable range, and even reproduce simplified radial velocity estimates using archival data. The key is to explain your sources of error clearly.

Where can I find real examples of star spectra and line data?

You can browse and download real spectra from the SDSS SkyServer and ESO’s archive. For line wavelengths and atomic data, the NIST Atomic Spectra Database is a standard reference used by professionals.

Which of the 3 practical examples is best for a middle school or early high school science fair?

For middle school, comparing star colors and temperatures is usually the best example because it’s visually intuitive and equipment-light. For early high school, identifying elements from absorption lines works well. The Doppler shift project is better suited to upper high school or early college students who are comfortable with data analysis and basic coding.

By building your project around these 3 practical examples of analyzing star light spectrum—and layering in a few of the extra variations—you’ll have a science fair entry that looks and feels like real astronomy. You’re not just pointing a telescope; you’re doing physics with starlight.