FITS to TAR Converter
Processing entirely on your device — large files may take a moment.
FITS (Flexible Image Transport System) is the data format of professional astronomy — every image carries a human-readable header with telescope, exposure and world coordinates alongside the raw pixel data. TAR preserves the exact file tree and permissions that Linux tooling expects.
Because the whole conversion happens on your device, it is instant, unlimited and genuinely private — no accounts, no watermarks, no files on anyone's server. Multiple files are converted in one go.
How FITS compares to TAR
| FITS | TAR | |
|---|---|---|
| Compression | None (optionally Rice/GZIP) | None (pair with gzip/zstd) |
| Best for | Telescope frames, science data | Linux packaging and source trees |
How to convert FITS to TAR
- 1
Select your files
Select your FITS file — it never leaves your device.
- 2
Convert instantly
The engine packs the file, byte for byte, into a TAR container — no re-encoding, no quality change.
- 3
Download results
Download the finished TAR archive.
About the FITS format
FITS (Flexible Image Transport System) has carried professional astronomy data since 1981: every file opens with a plain-text header that records telescope, instrument, exposure, filters and world coordinates, followed by raw pixel arrays — often 16-bit or float, sometimes data cubes.
Values can be negative or far above display range, so FITS never looks right in a photo viewer. Converting to PNG applies a simple scaling pass that reveals the nebula or galaxy in the numbers — good for previews, while science pipelines keep the original.
+Strengths
- ✓Self-documenting science headers
- ✓High bit depth (16/32-bit, float)
- ✓The standard of every observatory
!Limitations
- −Not display-ready
- −Files are large and uncompressed
About the TAR format
TAR (tape archive) is Unix's fifty-year-old answer to bundling: it concatenates files with headers into a single stream, preserving POSIX permissions, ownership and symlinks — but compressing nothing. It is the container half of the classic .tar.gz pairing and the native format of Linux source trees and backups.
Being pure bundling, TAR pairs with a compressor: gzip (the classic), bzip2, zstd. Alone, a TAR is the same size as its contents. Windows 10+ ships bsdtar, so even Windows can unpack it now — permissions aside, where NTFS has no room to be faithful.
+Strengths
- ✓Preserves Unix permissions and symlinks
- ✓Streamable: works over pipes and tapes
- ✓The standard of Linux distribution and backup
!Limitations
- −No compression by itself
- −No built-in encryption
- −Permissions meaningless on Windows filesystems
Why convert FITS to TAR?
Converting makes sense where the strengths of TAR meet what FITS cannot give you. Preserves Unix permissions and symlinks Meanwhile Not display-ready One pass through the converter above puts your file on the right side of that trade-off.
Frequently asked questions
Is this FITS to TAR converter really free?
Yes — completely free, with no sign-up, no watermark and no daily conversion limits. The site is supported by advertising.
Are my files uploaded to a server?
No. The conversion runs entirely inside your browser using WebAssembly, so your files never leave your device — that is what makes it instant and private.
Does it work on Windows, Mac, iPhone and Android?
Yes. Anything with a modern browser works: Windows, macOS, Linux, Android and iOS. No software installation is required.
Will I lose quality converting FITS to TAR?
No — TAR is a lossless format, so every pixel of the converted image matches your original FITS file. You can also adjust the quality/size balance before converting when the target format supports compression.
Will transparent areas survive the conversion to TAR?
Transparency is kept whenever TAR actually supports an alpha channel. If the target format has none (like JPG), transparent areas are flattened onto a white background — that is a property of the format, not of this tool.
What happens to EXIF data and other metadata?
Conversions here re-encode the image, and re-encoding generally does not carry the original metadata over. If the EXIF data of your FITS files matters (camera model, GPS, timestamps), keep the original file as the master and treat the converted copy as the shareable version.