Convert FITS to SUN Online
Convert FITS images to RAS format free, fast, and privately in your browser.
Drag & drop files here, or browse
Up to 20 images at once
How to convert FITS to SUN
Upload your files
Drag & drop or browse up to 20 FITS files at once.
Browser converts locally
Files convert to SUN in your browser - nothing is uploaded anywhere.
Download results
Save files individually or download everything as a ZIP bundle.
Why use this converter
100% Private - Nothing Uploaded
Your FITS files never leave your device. All conversion happens locally inside your browser using WebAssembly. Zero server contact.
Batch + ZIP Download
Convert up to 20 FITS files to RAS at once and download them all as a single ZIP archive in one click.
High Quality Output
Powered by ImageMagick WASM for accurate FITS to RAS conversion every time.
Instant Conversion
Your FITS files convert to RAS in seconds using WebAssembly - no waiting, no queues.
Frequently asked questions
Upload your FITS files by dragging them into the drop zone or clicking Browse. Select up to 20 files at once, then click Convert. Your files are processed locally in your browser and ready to download in seconds - no account or internet connection needed after the page loads.