fitsio-pure

Space data. Pure Rust.

FITS is a foundation of astronomical imaging. fitsio-pure makes those files accessible through a Rust implementation with no C dependencies and no unsafe code. Its core works with alloc; filesystem and compatibility APIs are optional.

Inspect a FITS file in your browser

Open a synthetic star field or inspect your own FITS file. The real fitsio-pure 0.13.5 parser runs here as WebAssembly. Your file stays in your browser.

This compact viewer shows the primary header and previews uncompressed 2D primary images up to 4 million pixels. The library supports more formats and extensions. Download the synthetic sample · Demo source

Add FITS to your Rust project

cargo add fitsio-pure

For a familiar fitsio-style API, enable the optional compatibility layer:

cargo add fitsio-pure --features compat

Read your first FITS header

use fitsio_pure::{hdu::parse_fits, image::read_image_data};

fn main() -> Result<(), Box<dyn std::error::Error>> {
    let bytes = std::fs::read("image.fits")?;
    let fits = parse_fits(&bytes)?;
    let image = read_image_data(&bytes, fits.primary())?;
    println!("{} HDUs; pixels: {image:?}", fits.hdus.len());
    Ok(())
}

read_image_data returns raw typed pixels. Apply header scaling when you need calibrated values. In a browser, provide the file’s bytes instead of reading from a filesystem.

One format, many kinds of data

Image types include unsigned 8-bit, signed 16/32/64-bit, and 32/64-bit floating point. The core also reads RICE_1 and GZIP_1 tile-compressed images. Read the migration guide →