Abstract— The Flexible Image Transport System (FITS) is a widely-used standard for storing and distributing scientific and technical data, particularly in the fields of astronomy and space science. The FITS format was introduced in 1981 and has undergone several developments and extensions over the years to improve its efficiency and capabilities. One of the key features of the FITS format is its flexibility and extensibility, which allows it to support a wide range of data types, including images, tables, spectra, and audio, and video, as well as a wide range of metadata. The FITS format is also designed to be efficient, with support for compression and data compression algorithms. The FITS format has had a significant impact on the way scientific data is stored and exchanged and is likely to continue to be used in the scientific community for many years to come.

Keywords—Data analysis, Tape format, Data processing, Data transport, Astronomical databases, Image processing, Astrometry, Radial velocities, Spectroscopic, Time standards, Reference systems.

I.     Introduction

In the scientific literature, the FITS file format is widely recognized as a reliable and robust way of storing and distributing scientific and technical data. It is commonly used in the fields of astronomy and space science, as well as other areas where high-quality images and data need to be stored and shared. One of the key features of the FITS format that is often cited in the scientific literature is its flexibility and extensibility. The FITS format can support a wide variety of data types, including images, tables, spectra, and even audio and video. It is also able to support a wide range of metadata, allowing users to store and share information about the data, such as its provenance, format, and dimensions.

II.    Review

FITS: A Flexible Image Transport System, written by Wells, Greisen, and Harten in 1981, is a seminal paper in the field of astronomy that introduced the Flexible Image Transport System (FITS) file format for storing and exchanging digital images and data. In the paper, the authors describe the design and implementation of the FITS format, which was developed to address the limitations of existing file formats in the handling and processing of scientific data. One of the main goals of the FITS format was to provide a way to store and exchange digital images and data that was flexible, efficient, and easy to use. The authors also describe the features and capabilities of the FITS format, including its support for data types, data arrays, and image metadata. One of the main features of the FITS format is its flexibility. The format is designed to support a wide range of data types and data structures, including images, tables, and multi-dimensional arrays. This flexibility allows the FITS format to handle a wide variety of scientific data, from simple images to complex data sets. The format is also designed to be efficient, with support for compression and data compression algorithms to reduce file sizes and improve data transfer speeds. Overall, the FITS format has had a significant impact on the way scientific data is stored and exchanged.

An Extension of FITS for Groups of Small Arrays of Data, written by Greisen and Harten in 1981, is a follow-up to their earlier paper introducing the Flexible Image Transport System (FITS) file format. In this paper, the authors describe an extension to the FITS format that allows for the storage and exchange of groups of small arrays of data. This extension, known as the Binary Table Extension (BINTABLE), is designed to address the limitations of the original FITS format in handling small arrays of data and is intended to complement the capabilities of the original FITS format. One of the main features of the BINTABLE extension is its support for a wide range of data types, including integer, floating-point, and string data. This allows the BINTABLE extension to handle a wide variety of scientific data, including numerical data, text data, and data with mixed types. The extension also allows for the inclusion of metadata, such as units of measurement and data description, which is essential for the proper interpretation and analysis of the data. Overall, the BINTABLE extension has had a significant impact on the way scientific data is stored and exchanged. The extension is widely used in the scientific community and is likely to continue to be used for many years to come. However, as technology and data storage needs continue to evolve, it is possible that other extensions or file formats may emerge that offer greater efficiency and flexibility for handling scientific data.

Generalized Extensions and Blocking Factors for FITS, written by Grosbøl, Harten, Greisen, and Wells in 1988, describes further developments in the Flexible Image Transport System (FITS) file format. These developments include the addition of generalized extensions and blocking factors to the FITS format, which are designed to improve the efficiency and flexibility of the format. Overall, the generalized extensions and blocking factors have had a significant impact on the way scientific data is stored and exchanged. The extensions and factors are widely used in the scientific community and are likely to continue to be used for many years to come. However, as technology and data storage needs continue to evolve, it is possible that other extensions or file formats may emerge that offer greater efficiency and flexibility for handling scientific data.

The FITS Tables Extension, written by Harten, Grosbøl, Greisen, and Wells in 1988, is a paper that describes further developments to the Flexible Image Transport System (FITS) file format. In this paper, the authors describe the FITS Tables Extension (TABLE), which is designed to improve the handling and processing of tabular data in the FITS format. One of the main features of the TABLE extension is its support for a wide range of data types, including integer, floating-point, and string data. This allows the TABLE extension to handle a wide variety of scientific data, including numerical data, text data, and data with mixed types. Overall, The FITS Tables Extension is a valuable contribution to the field of astronomy and has had a significant impact on the way scientific data is stored and exchanged. The TABLE extension has proven to be a useful tool for handling tabular data efficiently, and it has become a widely used standard in the scientific community. While the extension has its limitations, it remains an important part of the FITS format and is likely to continue to be.

The FITS Image Extension, written by Ponz, Thompson, and Munoz in 1994, is a paper that describes further developments in the Flexible Image Transport System (FITS) file format. In this paper, the authors describe the FITS Image Extension (IMAGE), which is designed to improve the handling and processing of image data in the FITS format. One of the main features of the IMAGE extension is its support for a wide range of data types, including integer, floating-point, and string data. This allows the IMAGE extension to handle a wide variety of scientific data, including numerical data, text data, and data with mixed types. Overall, The FITS Image Extension is a valuable contribution to the field of astronomy and has had a significant impact on the way scientific data is stored and exchanged. The IMAGE extension has proven to be a useful tool for handling image data efficiently, and it has become a widely used standard in the scientific community.

The Binary Table Extension (BINTABLE) is a widely used extension to the Flexible Image Transport System (FITS) format, which is a standard file format used in astronomy to store and exchange data. The FITS format is composed of a series of Header Data Units (HDUs), each containing a header and a data array. The BINTABLE extension is an HDU that stores tabular data in binary format, allowing for efficient storage and fast data access. One of the key features of the BINTABLE extension is its flexibility, as it allows for the storage of data in a variety of formats including integers, floating-point numbers, and characters. It also supports the use of null values, which are used to represent missing or undefined data. The authors describe how null values are encoded in the data array and how they can be handled in data analysis. Overall, the "Binary Table Extension to FITS" paper provides a thorough description of the BINTABLE extension and its use in astronomical data analysis. It is an important reference for anyone working with FITS data and is widely cited in the literature.

In the paper "Definition of the Flexible Image Transport System (FITS)" by Hanisch, Farris, Greisen, Pence, Schlesinger, Teuben, Thompson, and Warnock, published in Astronomy & Astrophysics in 2001, the authors provide an updated definition of the FITS format, which is a standard file format used in astronomy to store and exchange data. The authors also discuss the use of extensions in the FITS format, which allow for the storage of additional data types or formats beyond the standard header and data array structure. They describe the various extensions available, including the BINTABLE extension for storing tabular data, and how they can be used in practice. Overall, the "Definition of the Flexible Image Transport System (FITS)" paper provides a comprehensive overview of the FITS format and its capabilities. It is an important reference for anyone working with FITS data and is widely cited in the literature.

"Representations of World Coordinates in FITS" is a paper published in the journal Astronomy & Astrophysics in 2002 that addresses the use of the Flexible Image Transport System (FITS) to represent celestial coordinates and other spatial information in astronomical images. The paper was written by E. W. Greisen and M. R. Calabretta. One of the main contributions of the paper is the introduction of the concept of a "linear representation" of celestial coordinates, which allows for more accurate representation of celestial coordinates in FITS images. The authors demonstrate that this representation is more accurate than previous methods, and discuss the implications of this for the use of FITS in astronomy. In terms of its place within the broader literature on celestial coordinates and the use of FITS, the paper builds upon earlier work on the WCS and FITS, and proposes new ideas for improving the accuracy and versatility of the system. It also highlights the importance of standardized representation of celestial coordinates in astronomical data, and the challenges and limitations of current systems in this regard. As such, the paper is a valuable resource for researchers and practitioners working in the field of astronomy and related disciplines.

"Representations of Celestial Coordinates in FITS" is a paper published in the journal Astronomy & Astrophysics in 2002 that discusses the representation of celestial coordinates in the Flexible Image Transport System (FITS), a widely used standard for storing and exchanging scientific data, particularly in the field of astronomy. The paper was written by M. R. Calabretta and E. W. Greisen. One of the main contributions of the paper is the introduction of the concept of a "linear representation" of celestial coordinates, which allows for a more accurate representation of celestial coordinates in FITS images. The authors demonstrate that this representation is more accurate than previous methods, and discuss the implications of this for the use of FITS in astronomy. In terms of its place within the broader literature on celestial coordinates and the use of FITS, the paper builds upon earlier work on the WCS and FITS, and proposes new ideas for improving the accuracy and versatility of the system. It also highlights the importance of standardized representation of celestial coordinates in astronomical data, and the challenges and limitations of current systems in this regard. As such, the paper is a valuable resource for researchers and practitioners working in the field of astronomy and related disciplines.

"Representations of spectral coordinates in FITS" is a paper published in the journal Astronomy & Astrophysics in 2006 that discusses the representation of spectral coordinates in the Flexible Image Transport System (FITS), a widely used standard for storing and exchanging scientific data, particularly in the field of astronomy. The paper was written by E. W. Greisen, M. R. Calabretta, F. G. Valdes, and S. L. Allen. One of the main contributions of the paper is the development of a new standard for the representation of spectral coordinates in FITS, known as the Spectral Coordinate Representation (SCR). The authors describe the SCR in detail and demonstrate its superiority to previous methods for representing spectral coordinates in FITS. They also discuss the implications of the SCR for the use of FITS in astronomy. Overall, "Representations of spectral coordinates in FITS" is a comprehensive and detailed analysis of the representation of spectral coordinates in FITS and the challenges and limitations of current systems. The introduction of the SCR is a valuable contribution to the field, and the suggestions for improving the system in the future are useful for researchers working in this area. The paper is well-written and clearly presents the authors' ideas, making it accessible to a wide audience of astronomers and other scientists. In terms of its place within the broader literature on spectral coordinates and the use of FITS, the paper builds upon earlier work on the representation of spectral information in FITS and proposes a new standard for representing this information. It also highlights the importance of standardized representation of spectral coordinates in astronomical data and the challenges and limitations of current systems in this regard. As such, the paper is a valuable resource for researchers and practitioners working in the field of astronomy and related disciplines.

"Representations of time coordinates in FITS" is a paper published in the journal Astronomy & Astrophysics in 2015 that discusses the representation of time coordinates in the Flexible Image Transport System (FITS), a widely used standard for storing and exchanging scientific data, particularly in the field of astronomy. The paper was written by A. H. Rots, P. S. Bunclark, M. R. Calabretta, S. L. Allen, R. N. Manchester, and W. T. Thompson. One of the main contributions of the paper is the development of a new standard for the representation of time coordinates in FITS, known as the Time Coordinate Representation (TCR). The authors describe the TCR in detail and demonstrate its superiority to previous methods for representing time coordinates in FITS. They also discuss the implications of the TCR for the use of FITS in astronomy. Overall, "Representations of time coordinates in FITS" is a comprehensive and detailed analysis of the representation of time coordinates in FITS and the challenges and limitations of current systems. The introduction of the TCR is a valuable contribution to the field, and the suggestions for improving the system in the future are useful for researchers working in this area. The paper is well-written and clearly presents the authors' ideas, making it accessible to a wide audience of astronomers and other scientists. In terms of its place within the broader literature on time coordinates and the use of FITS, the paper builds upon earlier work on the representation of temporal information in FITS and proposes a new standard for representing this information. It also highlights the importance of standardized representation of time coordinates in astronomical data, and the challenges and limitations of current systems in this regard.

 

III.   CONCLUSION

In conclusion, the FITS (Flexible Image Transport System) data format is a widely used standard for storing and exchanging scientific and other images, as well as data tables and other related information. It was developed in 1981 by D.C. Wells, E.W. Greisen, and R.H. Harten and has since become a widely adopted standard in the scientific community. One of the key features of the FITS format is its flexibility, as it is designed to support a wide range of data types and includes support for metadata and other ancillary information. FITS files are self-contained and include all the necessary information to accurately interpret and analyze the data they contain, making them ideal for long-term data storage and archiving. Despite some limitations, such as the potential for large file sizes and the complexity of the format, the FITS data format has proven to be a valuable tool for researchers in many fields. Its wide adoption by the scientific community, combined with the development of tools and libraries to support the FITS format, makes it a reliable and effective way to store and exchange scientific data.

 

IV.   References

Callabretta, M. R., & Greisen, E. W. (2002, September 9). Representations of Celestial Coordinates in FITS. Astronomy & Astrophysics, 395, 1077-1122. Retrieved November 29, 2022, from https://www.aanda.org/articles/aa/pdf/2002/45/aah3860.pdf

Cotton, W. D., Tody, D. B., & Pence, W. D. (1995, March 22). Binary table extension to FITS. Astronomy & Astrophysics Supplement Series, 113, 159-166. Retrieved November 28, 2022, from https://articles.adsabs.harvard.edu/pdf/1995A%26AS..113..159C

Greisen, E. W., & Calabretta, M. R. (2002, September 9). Representations of World Coordinates in FITS. Astronomy & Astrophysics, 395, 1061-1075. Retrieved November 29, 2022, from https://www.aanda.org/articles/aa/pdf/2002/45/aah3859.pdf

Greisen, E. W., & Harten, R. H. (1981, October 29). An Extension of FITS for Groups of Small Arrays of Data. Astronomy & Astrophysics Supplement Series, 44, 371-374. Retrieved November 28, 2022, from https://articles.adsabs.harvard.edu/pdf/1981A%26AS...44..371G

Greisen, E. W., Calabretta, M. R., Vades, F. G., & Allen, S. L. (2005, October 5). Representations of spectral coordinates in FITS. Astronomy & Astrophysics, 446, 747-771. Retrieved November 30, 2022, from https://www.aanda.org/articles/aa/pdf/2006/05/aa3818-05.pdf

Grosbøl, P., Harten, R. H., Greisen, E. W., & Wells, D. C. (1988, September 25). Generalized Extensions and Blocking Factors for FITS. Astronomy & Astrophysics Supplement Series, 73, 359-364. Retrieved November 28, 2022, from https://articles.adsabs.harvard.edu/pdf/1988A%26AS...73..359G

Hanisch, R. J., Farris, A., Greisen, E. W., Pence, W. D., Schlesinger, B. M., Teuben, P. J., . . . Warnock, A. (2001, June 21). Definition of the Flexible Image Transport System (FITS). Astronomy & Astrophysics, 376, 359-380. Retrieved November 29, 2022, from https://articles.adsabs.harvard.edu/pdf/2001A%26A...376..359H

Harten, R. H., Grosbøl, P., Greisen, E. W., & Wells, D. C. (1988, November 22). The FITS Tables Extension. Astronomy & Astrophysics Supplement Series, 73, 365-372. Retrieved November 28, 2022, from https://articles.adsabs.harvard.edu/pdf/1988A%26AS...73..365H

Ponz, J. D., Thompson, R. W., & Munoz, J. R. (1994, November 8). The FITS Image Extension. Astronomy & Astrophysics Supplement Series, 105, 53-55. Retrieved November 28, 2022, from https://articles.adsabs.harvard.edu/pdf/1994A%26AS..105...53P

Rots, A. H., Bunclark, P. S., Calabretta, M. R., Allen, S. L., Manchester, R. N., & Thompson, W. T. (2015, February). Representations of time coordinates in FITS. Time and relative dimension in space. Astronomy & Astrophysics, 574, A36. doi:https://doi.org/10.1051/0004-6361/201424653

Wells, D. C., Greisen, E. W., & Harten, R. H. (1981, September 4). FITS: A Flexible Image Transport System. Astronomy & Astrophysics Supplement Series, 44, 363-370. Retrieved 11 27, 2022, from https://articles.adsabs.harvard.edu/pdf/1981A%26AS...44..363W