FITS to TAR.GZ Converter
Processing entirely on your device — large files may take a moment.
TAR.GZ is what open-source projects and Linux servers expect to receive. If your files are still in FITS format, this page is the shortcut: 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.
This converter runs entirely in your browser using WebAssembly — your files never leave your device, nothing is uploaded, and there are no watermarks, sign-ups or queues. Drop in several files at once to convert them as a batch.
How FITS compares to TAR.GZ
| FITS | TAR.GZ | |
|---|---|---|
| Compression | None (optionally Rice/GZIP) | gzip (DEFLATE) |
| Best for | Telescope frames, science data | Source releases and backups |
How to convert FITS to TAR.GZ
- 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.GZ container — no re-encoding, no quality change.
- 3
Download results
Download the finished TAR.GZ 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.GZ format
TAR.GZ is the classic Unix distribution shape: a TAR bundle squeezed through gzip (DEFLATE-based). Every Linux package of source code, every Apache tarball, every data-science dataset arrives this way. Decompression is a pipeline — untar the gzip stream — and the format is understood everywhere Unix ideas went.
gzip compresses the whole archive as one stream, which keeps ratio decent for text-heavy trees but means reaching file #400 requires decompressing the previous 399. Modern alternatives (zstd) are faster at similar ratios, yet tar.gz remains the safest common denominator.
+Strengths
- ✓Universally understood on Unix-like systems
- ✓Good ratio for text and source trees
- ✓Preserves Unix permissions via TAR
!Limitations
- −Single stream — no random access
- −Slower than modern zstd
- −Two-step format (tar + gzip)
Why convert FITS to TAR.GZ?
Think of it as moving your file to the container that fits the job. Not display-ready TAR.GZ works differently: Universally understood on Unix-like systems If any of that sounds like your task, run the conversion — it takes seconds and nothing leaves your device.
Frequently asked questions
Is this FITS to TAR.GZ 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.GZ?
No — TAR.GZ 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.GZ?
Transparency is kept whenever TAR.GZ 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.
Can I convert several FITS files at once?
Yes — drop as many files as you like into the tool and they are converted in one batch. When more than one file comes out, everything is bundled into a ZIP for a single download.