How to Convert FITS to SUN — Quick & Free
Fast, instant FITS to SUN conversion. No signup required. Just drop your .fits file and get .sun in seconds.
Batch Settings
About FITS to SUN Conversion
Short answer: yes, you can convert FITS to SUN online for free, and quality is well preserved with the right settings. Just upload your .fits file to CocoConvert, pick SUN as the output, and click Convert. The whole process takes seconds.
Now for the details. FITS is a widely used file format. SUN is a widely used file format. Converting between these two formats lets you convert between formats quickly.
Your FITS file is decoded and re-encoded as SUN. Converting FITS to SUN maintains high quality with CocoConvert's optimised encoder settings.
CocoConvert runs entirely online — no software to install, no account to create. Your files are encrypted during upload (TLS), processed on isolated servers in Germany, and permanently deleted after 24 hours. It works in Chrome, Safari, Firefox, Edge, and all mobile browsers.
Need to convert more than one file? Free users can do 5 per hour. Pro gets 100 per hour with files up to 5 GB each.
How to Convert FITS to SUN
- 1
1. Upload FITS
Drop your .fits file onto the page (or tap "Browse" on mobile). Add multiple files for batch conversion.
- 2
2. Select SUN
Choose .sun from the output dropdown. Settings are pre-configured for best results.
- 3
3. Convert
One click. The server handles all the heavy lifting using FFmpeg and Sharp.
- 4
4. Download
Your .sun file is ready. Download it directly or get all files as a zip archive.
What Happens When You Convert FITS to SUN
Your FITS file is decoded and re-encoded as SUN.
Your FITS file is uploaded and validated
The file is decoded (parsed into its raw data)
The data is re-encoded in SUN format
The converted file is ready for download
Format Comparison
FITS
.fits file
| Extension | .fits |
| MIME Type | image/fits |
| Category | Image |
SUN
.sun file
| Extension | .sun |
| MIME Type | image/x-sun-raster |
| Category | Image |
Should You Convert FITS to SUN?
When to Convert
- ✓When you need a SUN file
Frequently Asked Questions
Is FITS to SUN conversion free?
Yes. CocoConvert offers free FITS to SUN conversion with generous daily limits — 25 minutes of processing time and up to 5 files per hour (250 MB each). Pro plans remove these limits.
How fast is FITS to SUN conversion?
Most files convert in 2–10 seconds depending on size. Large image files may take 30 seconds. Batch jobs process in parallel for maximum speed.
What happens to my files after conversion?
Your uploaded FITS file and the converted SUN file are both automatically deleted from our servers within 24 hours. They are never shared, sold, or analysed.
Does converting FITS to SUN lose quality?
Converting FITS to SUN maintains high quality with CocoConvert's optimised encoder settings.
Can I convert SUN back to FITS?
Yes, CocoConvert supports SUN to FITS conversion as well. However, if the original conversion involved lossy compression, converting back won't recover the lost data.
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