Eric W. Greisen

I am a Scientist at the National Radio Astronomy Observatory. I was stationed at NRAO's headquarters in Charlottesville, Virginia for about 28 years. I am now fully transferred to NRAO's Array Operations Center in Socorro, NM. My main job at the present time is to develop and maintain the software package known as AIPS. I am also involved in FITS matters especially in the development of new standards for representing coordinate information. I even find time for a bit of life. A plain-text version of my curriculum vitae is available.

My pages on these matters include the following items:

• : my father passes away on March 17, 2007. Click for obituary and pictures including the July 2007 Physics Today obituary and 2 draft BAAS obituaries.
  
  
• : Van Biesbroeck Prize awarded to me by the AAS January 2005.
  
  
• FITS matters: updates on the World Coordinates proposal and the historical record. See also below for the current proposed papers. The main FITS pages are maintained by Don Wells.
  
  
• life: pictures from New Mexico (4/00-1/06), Oregon (10/04) Texas (4/04, 4/03 and 2/01), Alaska (5-6/02), Southern California (9/00), Hawaii (10/99), Virginia (12/99), and Maryland (11/99) and much more.
  
  
• CVX AIPS: remarks about some older releases and a poster and paper on uncertainties in Gaussian fitting (Oct 2001).

I have worked on several publications in 2002. I gave an invited talk (gzipped 2807999 bytes or uncompressed 3895373 bytes) on Wide-field Imaging in Classic AIPS at the International URSI meeting in Maastricht Holland in August. It was accompanied by a short paper (665829 bytes). I have had two chapters published in the book Information Handling in Astronomy - Historical Vistas, edited by Andre Heck (Kluwer, Astrophysics and Space Science Library, 285). One was a chapter on AIPS (compressed 2295579 bytes or uncompressed 9459219 bytes). The other was a chapter on FITS (compressed 785182 bytes or uncompressed 2948982 bytes). Both of these were educational experiences, especially when I had to review the scientific achievements of the VLA and VLBA. My old lecture on the early history of AIPS from the Barryfest is also available.

I have worked with Mark Calabretta off and on since 1992 on a detailed proposal for representing world coordinates in FITS. There will now be four papers: I on general matters, II on ideal celestial coordinates, III on ideal spectral coordinates, and IV on distortion corrections used to convert real instruments into these ideal coordinates. Papers I and II have been published by Astronomy & Astrophysics and accepted into the FITS standard for general use by the IAU. Paper III has been published in Astronomy & Astrophysics and has been endorsed by the IAU FITS working group. Paper IV is being developed. The A&A versions of I, II, and III are available below.

1. Representations of world coordinates in FITS by Greisen and Calabretta (246829 bytes pdf file from A&A) A&A, Volume 395, pages 1061-1075
2. Representations of celestial coordinates in FITS by Calabretta and Greisen (1279957 bytes pdf file from A&A), A&A, Volume 395, pages 1077-1122
3. Representations of spectral coordinates in FITS by Greisen, Calabretta, Valdes, and Allen (gzipped 204653 bytes) or unzipped (551653 bytes) or pdf (769502 bytes) astro-ph/0507293, A&A, Volume 446, pages 747-771
4. Representations of spectral coordinates in FITS by Greisen, Calabretta, Valdes, and Allen (gzipped 206532 bytes) or unzipped (563395 bytes) or pdf (931812 bytes) 07-October-2005, red shows changes since submitted to A&A.

Papers I and II were submitted to the North American FITS Committee of the AAS and were accepted by a vote of 15-0 with 3 non-voting. The Japanese and European FITS Committees have also approved them unanimously. The FITS Working Group of the IAU then accepted them on December 18, 2002 by a vote of 14-0 with 2 non-voting. Paper III has also been approved by the regional and IAU FITS Committees and published. Paper IV has been worked on, but has taken a back seat while we polish Papers I, II, and III.

The text of a proposal by Steve Allen and Doug Mink for "Concatenation of FITS World Coordinate Systems" is also now available for general review. This was raised on the fitswcs mailing list on 2002/01/01 and following and ideally would have been included in Paper I. However, we felt that the FITS community had not had adequate time to review it, yet we didn't want to delay Paper I further. Thus it is presented as a separate proposal.

General comments on paper IV may be sent to fitswcs@nrao.edu which is a general mail exploder for discussion of such matters. Typographical corrections are best just sent to the authors.