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FTS (.fts)

.fts file signature | application/fits

Flexible Image Transport System (FITS) is a scientific data file format developed by astronomy researchers and maintained through the IAU FITS Working Group and related standards bodies. It is used for storing astronomical images, spectra, tables, and other observational data in observatories, research archives, and analysis software. FITS has a long history in scientific computing and remains widely supported; files are generally safe, though large datasets may require specialized viewers.

Safe

Magic Bytes

Offset 0
53 49 4D 50 4C 45 20 20 3D 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 54

Sources: Apache Tika

All Known Signatures

2 signature variants are documented for .fts files across multiple sources.

Hex Signature Offset Sources
53 49 4D 50 4C 45 20 20 3D 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 54 0 Apache Tika
53 49 4D 50 4C 45 20 20 3D 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 54 0 Apache Tika

Extension

.fts

MIME Type

application/fits

Byte Offset

0

Risk Level

Safe

Validation Code

How to validate .fts files in Python

Python 
def is_fts(file_path: str) -> bool:
    """Check if file is a valid FTS by magic bytes."""
    signature = bytes([0x53, 0x49, 0x4D, 0x50, 0x4C, 0x45, 0x20, 0x20, 0x3D, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x54])
    with open(file_path, "rb") as f:
        return f.read(30) == signature

How to validate .fts files in Node.js

Node.js 
function isFTS(buffer: Buffer): boolean {
  const signature = Buffer.from([0x53, 0x49, 0x4D, 0x50, 0x4C, 0x45, 0x20, 0x20, 0x3D, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x54]);
  return buffer.subarray(0, 30).equals(signature);
}

How to validate .fts files in Go

Go 
func IsFTS(data []byte) bool {
    signature := []byte{0x53, 0x49, 0x4D, 0x50, 0x4C, 0x45, 0x20, 0x20, 0x3D, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x54}
    if len(data) < 30 {
        return false
    }
    return bytes.Equal(data[:30], signature)
}

API Endpoint

GET /api/v1/fts
curl https://filesignature.org/api/v1/fts

See the full API documentation for all endpoints and parameters.

Related Formats

.fit .fits

Frequently Asked Questions

What is a .fts file?

A .fts file is identified by the magic bytes 53 49 4D 50 4C 45 20 20 3D 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 54 at byte offset 0. Flexible Image Transport System (FITS) is a scientific data file format developed by astronomy researchers and maintained through the IAU FITS Working Group and related standards bodies. It is used for storing astronomical images, spectra, tables, and other observational data in observatories, research archives, and analysis software. FITS has a long history in scientific computing and remains widely supported; files are generally safe, though large datasets may require specialized viewers.

What are the magic bytes for .fts files?

The magic bytes for FTS files are 53 49 4D 50 4C 45 20 20 3D 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 54 at byte offset 0. These bytes uniquely identify the file format regardless of the file extension.

How do I validate a .fts file?

To validate a .fts file, read the first bytes of the file and compare them against the known magic bytes (53 49 4D 50 4C 45 20 20 3D 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 54) at offset 0. This is more reliable than checking the file extension alone, as extensions can be renamed.

What is the MIME type for .fts files?

The primary MIME type for .fts files is application/fits.

Is it safe to open .fts files?

FTS (.fts) files are generally safe to open. They are classified as low risk because they primarily contain data rather than executable code. However, always ensure files come from a trusted source.