AUTHORS

ABOUT

The Haystack Observatory Postprocessing system (HOPS) has a long lineage and history of revision and redesign. Initially it was born from the efforts of Alan Rogers in the late 70’s with a program called FRNGE which was written in Fortran and designed to be efficient on an HP-21MX (later renamed HP-1000) minicomputer. As hardware and software improvements proliferated, a rewrite of the Fortran toolset was launched in the early 90’s by Colin Lonsdale, Roger Cappallo and Cris Niell as driven by the needs of the geodetic community. The basic algorithms were adopted from FRNGE; but there was a complete rewrite of the code into (K&R) C and substantial revisions of the i/o, control and file structures resulting in the framework of the HOPS (<=3) system. This was followed by a substantial effort in the early-mid 2000’s to develop tools for optimizing SNR and to derive correction factors for data with imperfect coherence. While there is no definitive, published, HOPS reference in the literature, the Mark 4 Correlator paper (Whitney) touches upon the basic implementation available at that time period. Further evolution in the late 2000’s was provoked by the emergence of software correlation (DiFX Deller), and in the 2010’s by the needs of EHT-scale mm-VLBI. HOPS4 is a continuation/offshoot of the HOPS3 software and is a result of a re-architecture/redesign effort undertaken to make the software more modular and extensible in the face of ever increasing VLBI bandwidths and calibration complexity and is a work in progress.

Current Developers/Maintainers

  • John Barrett (jpb)

  • Geoff Crew (gbc)

  • Dan Hoak

Past Developers/Maintainers

  • Roger Cappallo (rjc) - supported the 1990’s rewrite and continued development until 2019

  • Colin Lonsdale (cjl) - architected the rewrite in the 1990’s

  • Cris Niell (cmn) - supported rewrite from Fortran to K&R C

  • Alan Rogers (aeer) - started it all with FRNGE in the late 1970’s

  • Kevin Dudevoir (kad) - supported the software late 2000s to 2015

Other Contributors

  • Alan Whitney

  • Arthur Niell (aen)

  • Brian Corey (bec)

  • Dan Smythe

  • John Ball (jab)

  • Sheperd Doeleman

  • Chester Ruszczyk

  • Vincent Fish

  • Lynn Matthews

  • Pedro Elosegui

  • Lindy Blackburn

This list is non-exhaustive and reflects major contributions.