What is MIME type "application/fits"?

A MIME type is a string that tells browsers and other tools how to handle a particular kind of file.

The MIME type application/fits is used for files following the Flexible Image Transport System standard. This format is common in astronomy for storing digital images and scientific data.

It embeds a detailed header that explains the contents of the file. This header holds metadata like observation details and calibration info. The format supports multi-dimensional arrays and tables, which helps scientists analyze complex datasets.

Used to store astronomical images and spectra.
Houses extensive metadata for data integrity.
Supported by many scientific software suites and libraries.

Files with the extensions FITS, FIT, and FTS follow this standard.

For more details on the format, visit the NASA FITS page.

Associated file extensions

.fit, .fts, .fits

Usage Examples

HTTP Header

When serving content with this MIME type, set the Content-Type header:


    Content-Type: application/fits

HTML

In HTML, you can specify the MIME type in various elements:


    <a href="file.dat" type="application/fits">Download file</a>

Server-side (Node.js)

Setting the Content-Type header in Node.js:


    const http = require('http');    
    
    http.createServer((req, res) => {    
      res.setHeader('Content-Type', 'application/fits');    
      res.end('Content here');    
    }).listen(3000);

Associated file extensions

.fit, .fts, .fits

FAQs

How do I open a file with the MIME type application/fits?

You cannot open these files with standard photo viewers. You need specialized astronomical software like SAOImage DS9, FV (FITS Viewer), or programming libraries like Astropy (Python) to visualize and analyze the data inside .fits files.

Can web browsers display application/fits images natively?

No, modern browsers like Chrome, Firefox, and Edge do not natively render FITS files. To display them on a webpage, you must use a JavaScript library (such as fitsjs) or provide a link for the user to download the file.

How do I configure Apache to serve FITS files correctly?

To ensure your Apache server sends the correct application/fits header, add the following line to your .htaccess or httpd.conf file: AddType application/fits .fits .fit .fts. This helps the browser understand that the file contains scientific data.

Is image/fits a valid alternative to application/fits?

While you might see image/fits used in older systems, application/fits is the official MIME type registered with IANA. It is recommended to strictly use application/fits to ensure maximum compatibility with modern scientific tools.

How do I enable FITS support in Nginx?

You can add the MIME type definition to your mime.types file or directly inside your server block configuration. Use the directive: types { application/fits fits fit fts; } and reload Nginx to apply the changes.

Why does a FITS file look like text mixed with garbage symbols?

A FITS file consists of a human-readable ASCII header followed by binary data. If you open it in a text editor, you will see metadata (like telescope info) at the top, but the actual image or table data will appear as unreadable binary characters.

General FAQ

What is a MIME type?

A MIME (Multipurpose Internet Mail Extensions) type is a standard that indicates the nature and format of a document, file, or assortment of bytes. MIME types are defined and standardized in IETF's RFC 6838.

MIME types are important because they help browsers and servers understand how to process a file. When a browser receives a file from a server, it uses the MIME type to determine how to display or handle the content, whether it's an image to display, a PDF to open in a viewer, or a video to play.

MIME types consist of a type and a subtype, separated by a slash (e.g., text/html, image/jpeg, application/pdf). Some MIME types also include optional parameters.

How do I find the MIME type for a file?

You can check the file extension or use a file identification tool such as file --mime-type on the command line. Many programming languages also provide libraries to detect MIME types.

Why are multiple MIME types listed for one extension?

Different applications and historical conventions may use alternative MIME identifiers for the same kind of file. Showing them all helps ensure compatibility across systems.