OTB to FITS Converter
Processing entirely on your device — large files may take a moment.
Convert FITS frames to PNG or JPG to preview telescope data, or pack them into a ZIP for sharing. If your files are still in OTB format, this page is the shortcut: OTB is the Nokia OTA Bitmap — 1-bit monochrome images that old Nokia phones displayed as operator logos and picture messages.
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 to convert OTB to FITS
- 1
Select your files
Drag & drop your OTB 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 OTB format
The Nokia OTA Bitmap coder of the ImageMagick set — the retro-phone format is written natively by the magick.wasm engine, entirely in your browser.
Obscure coder formats like this are exactly what template-driven converters list and never actually convert — here it really works.
+Strengths
- ✓Written natively by ImageMagick
- ✓Runs entirely in your browser
- ✓Free, private, no watermarks
!Limitations
- −Niche format — few modern readers
- −Feature subset varies by coder
- −Keep the original for re-editing
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 OTB to FITS?
There is a concrete reason this conversion exists: Niche format — few modern readers FITS sidesteps that — Self-documenting science headers If that is your situation, the tool above settles it in seconds, entirely on your device.
Frequently asked questions
Is this OTB 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 OTB to FITS?
No — FITS is a lossless format, so every pixel of the converted image matches your original OTB file. You can also adjust the quality/size balance before converting when the target format supports compression.
Can I convert several OTB 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.