RAW to FITS Converter
Processing entirely on your device — large files may take a moment.
Camera RAW Photo and Flexible Image Transport System exist for different jobs: RAW is the unprocessed sensor data from cameras — Canon CR2/CR3, Nikon NEF, Sony ARW, Adobe DNG and friends. It holds maximum quality, but needs demosaicing before any normal app can show it. Convert FITS frames to PNG or JPG to preview telescope data, or pack them into a ZIP for sharing.
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 RAW compares to FITS
| RAW | FITS | |
|---|---|---|
| Compression | Lossless or lossy, per vendor | None (optionally Rice/GZIP) |
| Transparency | Not supported | Not supported |
| Animation | Not supported | Not supported |
| Metadata | Full capture parameters | Rich text header (WCS) |
| Best for | Photography masters and retouching | Telescope frames, science data |
How to convert RAW to FITS
- 1
Select your files
Drag & drop your RAW files onto the area above, or click to browse. You can add multiple files at once for batch conversion.
- 2
Convert instantly
Click "Convert to FITS". The conversion runs entirely inside your browser using WebAssembly — no upload, no queue, no waiting.
- 3
Download results
Download each converted FITS file individually, or grab everything at once as a ZIP archive.
About the RAW format
RAW is not one format but a family: each camera maker packages the sensor's barely-processed readout differently — Canon CR2/CR3, Nikon NEF, Sony ARW, Fujifilm RAF, Panasonic RW2, plus Adobe's open DNG attempt at standardization. Instead of finished pixels you get 12- or 14-bit linear data straight off the sensor, which is why every RAW must be demosaiced and rendered before any ordinary app can show it.
The payoff is latitude. Because white balance, sharpening and tone curve were never baked in, a RAW file tolerates several stops of exposure correction that would destroy a JPG. The cost is workflow: files run 20–100 MB, every vendor's flavor needs its own decoder, and sharing means exporting a finished JPG or PNG.
+Strengths
- ✓Maximum editing latitude — exposure and color can be re-decided later
- ✓12/14-bit depth avoids banding in shadows and skies
- ✓The archival master of digital photography
!Limitations
- −Unviewable without demosaicing — normal apps show nothing
- −Every camera vendor uses a different container
- −Large files (20–100 MB+)
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
Why convert RAW to FITS?
Converting makes sense where the strengths of FITS meet what RAW cannot give you. Self-documenting science headers Meanwhile Unviewable without demosaicing — normal apps show nothing One pass through the converter above puts your file on the right side of that trade-off.
Frequently asked questions
Is this RAW to FITS 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 RAW to FITS?
No — FITS is a lossless format, so every pixel of the converted image matches your original RAW file. You can also adjust the quality/size balance before converting when the target format supports compression.
Can I convert several RAW 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.
Will transparent areas survive the conversion to FITS?
Transparency is kept whenever FITS 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.