FITS Foreign File Encapsulation Convention

TL;DR

This paper introduces the FITS Foreign File Encapsulation Convention, a method for embedding arbitrary files within FITS files, enabling easy storage and retrieval of external data in astronomical data processing.

Contribution

It presents a new FITS convention for encapsulating foreign files, implemented in IRAF tools, facilitating data management in astronomical pipelines.

Findings

First use in 1999 for PNG graphics encapsulation

Provides a mechanism for storing complex file trees in FITS

Enables restoring embedded files to disk later

Abstract

This document describes a FITS convention developed by the IRAF Group (D. Tody, R. Seaman, and N. Zarate) at the National Optical Astronomical Observatory (NOAO). This convention is implemented by the fgread/fgwrite tasks in the IRAF fitsutil package. It was first used in May 1999 to encapsulate preview PNG-format graphics files into FITS files in the NOAO High Performance Pipeline System. A FITS extension of type 'FOREIGN' provides a mechanism for storing an arbitrary file or tree of files in FITS, allowing it to be restored to disk at a later time.