Radio Astronomy on GitHub¶

A curated, link-verified field guide to radio-astronomy source code — the organizations that publish it, the repositories worth knowing, and the people who maintain them. Any language counts: the field's tools are a mix of C++, Python, CUDA, Fortran, and HDL.

This page complements the institution-focused Resources, the hardware-focused Projects, Kits & Hacks, the instrument catalogue Radio Telescopes, and the Bibliography. Where a tool is used or taught in the course, the chapter is cross-linked; where a tool has a canonical paper, it is cited.

Verified mid-2026 — and a caveat on hosting

Every GitHub link below was checked live. But radio astronomy predates GitHub, so several major tools live elsewhere — CASA (pip wheels), WSClean and AOFlagger (GitLab), RASCIL and SatNOGS (GitLab), PSRCHIVE / DSPSR / heimdall (SourceForge), tempo2 (Bitbucket). Those are gathered under Beyond GitHub so the picture is honest, not just GitHub-shaped.

At a glance¶

143 catalogued entries across 18 categories — generated from docs/data/radio_github.yml by scripts/github_stats.py (kept in sync by a test).

Kind	Entries
Organizations & collaborations	36
Software repositories	86
People	12
Beyond GitHub (GitLab / SourceForge)	9
Total	143

Organizations & collaborations¶

The institutional and collaboration accounts that publish the field's software.

Interferometry & imaging software groups¶

casacore — the foundational C++ data model (Measurement Set, Tables, coordinates, images) that nearly every interferometry pipeline links against. Repos: casacore, python-casacore. Paper: CASA Team 2022, PASP 134, 114501. In the course: Ch 12, Ch 41.
casangi — NRAO's next-generation, Python-native CASA stack (xradio xarray/Zarr I/O, graphviper Dask parallelism, casadocs). The successor to the CASA monolith. Paper: McMullin et al. 2007, ASPC 376, 127.
RadioAstronomySoftwareGroup (RASG) — the Python visibility ecosystem: pyuvdata, pyuvsim, pyradiosky, and the rasg-datasets the course fetches from. Paper: Hazelton et al. 2017, JOSS 2, 140. In the course: Ch 12, Ch 16.
ratt-ru — Rhodes University's MeerKAT/SKA-era calibration & imaging algorithms: codex-africanus (RIME building blocks), QuartiCal (Dask Jones-matrix calibration), dask-ms, tigger (sky-model viewer). Home of the open textbook Fundamentals of Radio Interferometry. In the course: Ch 41.
lofar-astron — ASTRON's LOFAR stack: DP3 (streaming calibration/flagging), PyBDSF (source finder), RMextract (ionospheric RM correction). Paper: van Haarlem et al. 2013, A&A 556, A2. In the course: Ch 37, Ch 39.
ska-sa — SARAO / MeerKAT software: katdal (data access), katpoint (pointing/coordinates), montblanc (GPU RIME). Paper: Jonas 2009, IEEE Proc. 97, 1522.
ska-telescope — the SKA Observatory's GitHub presence (operational subsystems, global sky model). Note: most SKA code is on GitLab, with GitHub a partial mirror.
radio-astro-tools — the spectral-cube ecosystem: spectral-cube, radio-beam, pvextractor. In the course: Ch 11.
CARTAvis — CARTA, the web-based cube/image viewer for ALMA/VLA/SKA (carta-backend, carta-frontend). Paper: Wang et al. 2026, PASP 138, 024506.

Observatories & facilities¶

GreenBankObservatory — the GBT toolchain: dysh (the modern GBTIDL successor, Python spectral-line reduction), gbt-pipeline, gbtgridder.
MITHaystack — srt-py (the Small Radio Telescope), digital_rf (wideband recording format), HOPS (the EHT VLBI fringe-fitting suite). In the course: Ch 6, Projects.
jive-vlbi — JIVE / EVN correlator software: sfxc (software correlator), jive5ab (VLBI recording), PolConvert (used in ALMA-VLBI & the EHT). In the course: Ch 19.
MPIfR-BDG — the Effelsberg/MeerKAT backend group: pulsar/FRB acquisition firmware (mpikat, psrdada_cpp).
NCRA-TIFR — the uGMRT's group: the SPAM ionospheric calibration pipeline. Paper: Intema et al. 2017, A&A 598, A78.
ATNF — CSIRO-ATNF (ASKAP benchmarks, the deprecated yandasoft imager). Most ATNF pulsar code (PSRCHIVE, DSPSR) is on SourceForge.

Collaborations: pulsars, FRBs, SETI, the EHT¶

nanograv — the nanohertz-GW pulsar-timing-array collaboration: PINT (modern Python timing), enterprise (Bayesian PTA inference), tempo (the Fortran classic). Paper: Agazie et al. 2023, ApJ 951, L8. In the course: Ch 13, Ch 20.
CHIMEFRB — the largest FRB catalogue's backend: kotekan (real-time GPU pipeline), fitburst (burst modelling). Paper: CHIME/FRB 2021, ApJS 257, 59. In the course: Ch 18.
chime-experiment — the broader CHIME telescope stack (ch_pipeline, ch_util).
UCBerkeleySETI — Breakthrough Listen: blimpy (filterbank/GUPPI I/O), turbo_seti (Doppler-drift search), hyperseti (GPU successor). Paper: Enriquez et al. 2017, ApJ 849, 104. In the course: Ch 21.
eventhorizontelescope — the EHT's calibrated data releases (M87 2019, Sgr A 2022) and imaging pipelines. Paper: EHT 2019, ApJ 875, L1. In the course:* Ch 19.

SDR, amateur & education¶

gnuradio — the GNU Radio software-defined-radio framework behind most amateur and teaching radio astronomy. In the course: Ch 28.
WVURAIL — WVU's DSPIRA education program: gr-radio_astro (GNU Radio OOT modules), os_radio_astro_hw (open LNA hardware), dspira-lessons. In the course: Ch 28, Projects.
krakenrf — the KrakenSDR 5-channel coherent receiver: krakensdr_doa (direction finding / MUSIC), heimdall_daq_fw (coherent acquisition). In the course: Ch 17.
myriadrf — home of RASDR, the SARA-backed open-hardware Radio Astronomy SDR. In the course: Ch 30.
maserlib — Paris Observatory's maser4py, readers for low-frequency & planetary radio formats (Nançay, Radio JOVE, Voyager/Cassini). Paper: Cecconi et al. 2020, Data Science Journal 19, 12. In the course: Ch 23, and the basis for jansky.formats SPS/SPD readers.

Foundational ecosystem¶

astropy — the bedrock: astropy (coordinates, units, FITS, WCS, time) and astroquery (archive access — NRAO, ALMA, SIMBAD, VizieR, HEASARC). Plus reproject and regions. Paper: Astropy Collaboration 2022, ApJ 935, 167. In the course: used in essentially every chapter.

21 cm cosmology, intensity mapping & solar physics¶

HERA-Team — the Hydrogen Epoch of Reionization Array's software: hera_cal (redundant calibration), hera_sim, hera_qm (quality metrics), hera_pspec (power spectra), matvis (fast visibility simulator). In the course: Ch 6, Ch 41.
radiocosmology — the CHIME 21 cm-intensity-mapping m-mode stack: cora (sky simulation), driftscan, draco, caput. Paper: Shaw et al. 2015, PhRvD 91, 083514.
MWATelescope — the Murchison Widefield Array's modern Rust pipeline: mwa_hyperdrive (calibration), Birli (preprocessing). In the course: Ch 41.
EoRImaging — the MWA EoR power-spectrum pipeline (IDL): FHD (Fast Holographic Deconvolution), eppsilon (power-spectrum estimator). Paper: Barry et al. 2019, PASA 36, e026.
sunpy — the core solar-physics Python ecosystem, including the radio dynamic-spectrum package radiospectra. Paper: SunPy Community 2020, ApJ 890, 68. In the course: Ch 23.
spedas — pyspedas, the Python framework for heliophysics/CDAWeb data (Wind/WAVES, STEREO/WAVES, PSP, Solar Orbiter radio). In the course: Ch 23.
i4Ds — FHNW's institute for the e-Callisto solar-radio-spectrometer network: ecallisto_ng. Paper: Benz et al. 2009, SoPh 260, 375. In the course: Ch 23.
healpy — the healpy HEALPix Python ecosystem (the pixelisation behind the HI4PI map the course reads in Ch 11). Paper: Zonca et al. 2019, JOSS 4, 1298.
simonsobs — the Simons Observatory CMB stack (pixell, so_noise_models). In the course: Ch 22.
Cosmoglobe — Bayesian CMB + radio-foreground component separation (Commander). In the course: Ch 22, Ch 37.

Software repositories¶

Pulsar timing & analysis¶

nanograv/PINT — high-precision Python pulsar timing (residuals agree with TEMPO/TEMPO2 to ~10 ns). Python, BSD-3. Paper: Luo et al. 2021, ApJ 911, 45. In the course: Ch 13, Ch 20.
scottransom/presto — the most widely used pulsar search suite (FFT/acceleration/single-pulse search, folding). C/Python, GPL-2. Paper: Ransom et al. 2002, AJ 124, 1788. In the course: Ch 13.
mattpitkin/tempo2 (GitHub mirror) — the 1-ns relativistic timing package; canonical home on Bitbucket. C/C++/Fortran, GPL-3. Paper: Hobbs, Edwards & Manchester 2006, MNRAS 369, 655.
vallis/libstempo — Python/Cython wrapper around tempo2, the bridge into PTA workflows. MIT. In the course: Ch 20.
mattpitkin/psrqpy — scripted queries of the ATNF Pulsar Catalogue. Paper: Pitkin 2018, JOSS 3, 538.
NickSwainston/pulsar_spectra — Bayesian flux-density spectral fitting with a crowd-maintained catalogue. Paper: Swainston et al. 2022, PASA 39, e056.
v-morello/clfd — outlier-based RFI excision for folded pulsar archives. Paper: Morello et al. 2019, MNRAS 483, 3673. In the course: Ch 39.
nanograv/enterprise + enterprise_extensions — the Bayesian PTA framework behind the 2023 nanohertz-GW-background evidence. MIT. In the course: Ch 20.

Pulsar & FRB search, single-pulse & real-time pipelines¶

thepetabyteproject/your — "Your Unified Reader": one API over filterbank/PSRFITS/PSRDADA. Python, GPL-3. Paper: Aggarwal et al. 2020, JOSS 5, 2750. In the course: Ch 13, Ch 18.
FRBs/sigpyproc3 — numba-accelerated filterbank/PSRFITS I/O and search primitives (Python-3 rewrite of ewanbarr/sigpyproc). MIT.
v-morello/riptide — the Fast Folding Algorithm for long-period pulsar search. Paper: Morello et al. 2020, MNRAS 497, 4654.
ypmen/PulsarX — high-performance C++ folding/search for FAST & MeerKAT. Paper: Men & Barr 2024, A&A 679, A20.
ypmen/TransientX — fast single-pulse search pipeline. Paper: Men & Barr 2024, A&A 683, A183. In the course: Ch 18.
ewanbarr/peasoup — GPU FFT-based pulsar search (TRAPUM's engine).
cbassa/cdmt — GPU coherent dedispersion over many DM trials. Paper: Bassa et al. 2017. In the course: Ch 13.
kiyo-masui/burst_search — real-time FRB search in GUPPI data. In the course: Ch 18.
realfastvla/rfpipe — real-time interferometric FRB search for the VLA. Paper: Law et al. 2018, ApJS 236, 8. In the course: Ch 18.
ledatelescope/bifrost — GPU stream-processing framework for real-time pipelines. Paper: Cranmer et al. 2017, JAI 6, 1750007.

FRBs: classification, redshifts & populations¶

devanshkv/fetch — CNN classifier separating FRBs from RFI. Paper: Agarwal et al. 2020, MNRAS 497, 1661. In the course: Ch 18, Ch 38.
abatten/fruitbat — FRB redshift estimation from DM. Paper: Batten 2019, JOSS 4, 1399. In the course: Ch 18.
davidgardenier/frbpoppy — FRB population synthesis. Paper: Gardenier et al. 2019, A&A 632, A125.

Interferometric calibration & flagging¶

lofar-astron/DP3 — the LOFAR streaming flagging/averaging/calibration pipeline. C++, GPL-3. In the course: Ch 39, Ch 41.
ratt-ru/QuartiCal — Dask-based per-antenna Jones-matrix calibration (CubiCal's successor). In the course: Ch 41.
ratt-ru/codex-africanus — modular RIME / gridding / calibration algorithms with GPU support. Paper: Perkins et al. 2025, A&C (Africanus I).
saopicc/killMS — direction-dependent gain solver. Paper: Tasse 2014, A&A 566, A127. In the course: Ch 41.
ska-sa/montblanc — GPU RIME for Bayesian inference. Paper: Perkins et al. 2015, A&C 12, 73.
lofar-astron/prefactor — LOFAR direction-independent calibration. Paper: de Gasperin et al. 2019, A&A 622, A5.
lofar-astron/RMextract — ionospheric Faraday-rotation correction. In the course: Ch 37.

Imaging & deconvolution¶

saopicc/DDFacet — wide-field, direction-dependent faceted imager. Paper: Tasse et al. 2018, A&A 611, A87. In the course: Ch 9.
achael/eht-imaging — the EHT's regularised-maximum-likelihood VLBI imaging library (M87 & Sgr A shadows). Python, GPL-3. Paper: Chael et al. 2018, ApJ 857, 23. In the course:* Ch 19.
astrosmili/smili — sparse-modelling VLBI imaging. Paper: Akiyama et al. 2017, AJ 153, 159. In the course: Ch 19.
casangi/xradio — next-gen xarray/Zarr radio data I/O. In the course: Ch 16.

Visibility data, simulation & sky models¶

RadioAstronomySoftwareGroup/pyuvdata — read/write/convert UVFITS, Measurement Set, UVH5, MIRIAD. Paper: Hazelton et al. 2017, JOSS 2, 140. In the course: Ch 12, Ch 16.
RadioAstronomySoftwareGroup/pyuvsim — reference high-precision interferometer simulator. Paper: Lanman et al. 2019, JOSS 4, 1234.
ratt-ru/dask-ms — xarray/Dask interface to Measurement Sets. In the course: Ch 16.
ska-sa/katdal + katpoint — MeerKAT data access and pointing.

Spectral cubes, regions & viewers¶

radio-astro-tools/spectral-cube — lazy, WCS-aware analysis of HI/molecular-line cubes. In the course: Ch 11.
radio-astro-tools/radio-beam — synthesised-beam handling and common-resolution convolution. In the course: Ch 11.
radio-astro-tools/pvextractor — position-velocity diagrams from cubes. In the course: Ch 11.
astropy/reproject — WCS reprojection for multi-wavelength overlays. In the course: Ch 14.

SETI¶

UCBerkeleySETI/turbo_seti — the production Doppler-drift technosignature search. Paper: Enriquez et al. 2017, ApJ 849, 104. In the course: Ch 21.
UCBerkeleySETI/blimpy — Breakthrough Listen filterbank/GUPPI I/O. Paper: Price et al. 2019, JOSS 4, 1554. In the course: Ch 21, Ch 16.
bbrzycki/setigen — inject synthetic narrowband signals for pipeline validation & ML training. Paper: Brzycki et al. 2022, arXiv:2203.09668. In the course: Ch 21.

SDR toolchains¶

gnuradio/gnuradio — the SDR signal-processing framework. C++/Python, GPL-3. In the course: Ch 28.
osmocom/rtl-sdr + librtlsdr/librtlsdr — the RTL2832U userspace driver (rtl_sdr, rtl_power) and its community fork. C, GPL-2. In the course: Ch 5.
pyrtlsdr/pyrtlsdr — Pythonic RTL-SDR access (the sdr extra). In the course: Ch 5.
osmocom/gr-osmosdr — unified GNU Radio source/sink for dozens of SDR devices. In the course: Ch 28.
pothosware/SoapySDR — vendor-neutral SDR hardware API. BSL-1.0.
gqrx-sdr/gqrx — the GUI SDR receiver (spectrum/waterfall) built on GNU Radio. In the course: Ch 5.

Amateur single-dish, education & planetary¶

0xCoto/VIRGO — open-source spectrometer for amateur radio astronomy (HI line, continuum); the astro-virgo dependency and the engine behind PICTOR. Paper: Spanakis-Misirlis 2021, JOSS 6, 3067. In the course: Ch 29.
0xCoto/PICTOR — the free online 1.5 m radio telescope (web-scheduled drift scans). In the course: Ch 29.
MITHaystack/srt-py — control software for the teaching Small Radio Telescope. In the course: Ch 6, Projects.
WVURAIL/gr-radio_astro — DSPIRA GNU Radio modules (integrating spectrometer for the 21 cm line). In the course: Ch 28.
myriadrf/RASDR — the SARA RASDR open-hardware receiver + streamer. In the course: Ch 30.
maserlib/maser4py — low-frequency & planetary radio format readers (Radio JOVE, Voyager/Cassini). Paper: Cecconi et al. 2020, DSJ 19, 12. In the course: Ch 23.

VLF & lightning¶

ericgibert/supersid — monitor sudden ionospheric disturbances from VLF transmitter strength (Stanford/SARA SuperSID). In the course: Ch 27.
daedalus/vlfrx-tools — GPS-timestamped VLF toolkit (sferics, whistlers, meteor scatter). In the course: Ch 40, Projects.

21 cm cosmology, EoR & intensity mapping¶

The faint cosmological 21 cm signal drives its own software ecosystem — signal simulation, power-spectrum sensitivity, and the wide-field calibration/imaging that foreground removal demands.

21cmfast/21cmFAST — the canonical semi-numerical simulator of the cosmic 21 cm signal through cosmic dawn and reionization. Python/C, MIT. Paper: Murray et al. 2020, JOSS 5, 2582. In the course: Ch 6, Ch 22.
21cmfast/21CMMC — MCMC Bayesian inference of EoR astrophysics from the 21 cm power spectrum. Paper: Greig & Mesinger 2015. In the course: Ch 22, Ch 38.
sambit-giri/tools21cm — analysis of the large-scale EoR 21 cm signal (mock LOFAR/MWA/SKA observations, statistics). Paper: Giri et al. 2020, JOSS 5, 2363.
steven-murray/powerbox — Gaussian random fields with a specified power spectrum (mock density/21 cm boxes). Paper: Murray 2018, JOSS 3, 850.
rasg-affiliates/21cmSense — predicted sensitivity of a 21 cm array to the EoR power spectrum (thermal noise + foreground avoidance). Paper: Pober et al. 2014, ApJ 782, 66. In the course: Ch 6, Ch 8.
HERA-Team/hera_pspec — HERA delay-spectrum / quadratic power-spectrum estimation on calibrated visibilities. In the course: Ch 41.
EoRImaging/FHD — wide-field holographic deconvolution & calibration (MWA EoR). IDL, BSD-2. Paper: Sullivan et al. 2012, ApJ 759, 17. In the course: Ch 9.
MWATelescope/mwa_hyperdrive — fast GPU MWA calibration. Rust, MPL-2. In the course: Ch 41.
RadioAstronomySoftwareGroup/healvis — HEALPix-pixel visibility simulator (full-sky, for EoR pipeline tests). In the course: Ch 8.
nithyanandan/PRISim — precision radio-interferometer simulator (transit arrays, foregrounds). In the course: Ch 8.
AaronParsons/aipy — the PAPER experiment's foundational interferometry/calibration/imaging library. In the course: Ch 8, Ch 41.
radiocosmology/driftscan — m-mode transit analysis for 21 cm intensity mapping (CHIME). Paper: Shaw et al. 2014, ApJ 781, 57. In the course: Ch 22.

CMB, HEALPix & foreground maps¶

The CMB shares its tooling — all-sky HEALPix maps, angular power spectra, and the synchrotron / free-free foregrounds that are radio emission — with radio astronomy.

healpy/healpy — the Python HEALPix interface (read/write/ visualise all-sky maps, anafast power spectra). Python, GPL-2. Paper: Zonca et al. 2019, JOSS 4, 1298. In the course: Ch 22, Ch 11.
simonsobs/pixell — rectangular-pixel (flat-sky) CMB map analysis used by ACT/Simons Observatory. In the course: Ch 22.
mreineck/ducc (GitHub mirror of the MPCDF GitLab) — fast spherical-harmonic transforms & interferometric gridding (the SHT engine inside healpy and WSClean). In the course: Ch 22, Ch 8.
LSSTDESC/NaMaster — pseudo-\(C_\ell\) angular power spectra of masked spin-0/spin-2 (T & polarisation) maps. Paper: Alonso et al. 2019, MNRAS 484, 4127. In the course: Ch 22, Ch 37.
galsci/pysm — PySM 3: full-sky simulated Galactic foregrounds (synchrotron, free-free, dust, AME) + CMB. Paper: Zonca et al. 2021, JOSS 6, 3783. In the course: Ch 22, Ch 37.
simonsobs/so_noise_models — Simons Observatory noise/sensitivity forecasts (also used in 21 cm foreground work). In the course: Ch 22.
hpc4cmb/toast — time-ordered-data simulation & map-making for CMB experiments (POLARBEAR, BICEP, SO, CMB-S4). In the course: Ch 22.
Cosmoglobe/Commander — Bayesian Gibbs-sampling joint CMB + radio-foreground component separation (Planck/BeyondPlanck). Fortran, GPL-3. Paper: Eriksen et al. 2008, ApJ 676, 10. In the course: Ch 22, Ch 37.
cmbant/CAMB (theory) — the Boltzmann code for CMB power spectra the chapter compares maps against. Paper: Lewis et al. 2000, ApJ 538, 473. In the course: Ch 22.

Solar & heliophysics radio¶

Solar radio bursts, dynamic spectra, and the spacecraft radio receivers that track space weather. (The planetary/solar maser4py above also reads Wind/WAVES & STEREO/WAVES data.)

sunpy/sunpy — the core solar-physics library (maps, timeseries, Fido archive access for Wind/STEREO radio). Python, BSD-2. Paper: SunPy Community 2020, ApJ 890, 68. In the course: Ch 23, Ch 10.
sunpy/radiospectra — solar radio dynamic spectra: reads e-Callisto, STEREO/WAVES, Wind/WAVES, RSTN, and Nançay Decameter Array. In the course: Ch 23.
i4Ds/ecallisto_ng — fetch & analyse e-Callisto network spectrograms (with optional ML flare detection). Paper: Benz et al. 2009, SoPh 260, 375. In the course: Ch 23, Ch 15.
spedas/pyspedas — download/plot heliophysics CDAWeb data, including Wind/WAVES, STEREO/WAVES, PSP/FIELDS, and Solar Orbiter/RPW radio. Python, MIT. In the course: Ch 23.
maserlib/ExPRES — simulate planetary (and solar-wind-modulated) radio emission patterns. Paper: Hess & Zarka 2011, A&A 531, A29. In the course: Ch 23.
peijin94/LOFAR-Sun-tools — LOFAR solar dynamic-spectrum & imaging reduction (beam-formed HDF5, RFI, burst onset). In the course: Ch 23.
TCDSolar/SIDpy — process Stanford SuperSID receiver data to see solar-flare sudden ionospheric disturbances at VLF. In the course: Ch 27, Ch 23.

People — notable maintainers¶

Authors and maintainers of widely-used radio-astronomy software, with a public GitHub profile and a representative paper. (Listed for their public, professional open-source work.)

Scott Ransom — @scottransom: PRESTO & co-lead of PINT. Paper: Ransom et al. 2002, AJ 124, 1788. → Ch 13, Ch 20.
André Offringa — @aroffringa: WSClean & AOFlagger (primary home on GitLab). Paper: Offringa et al. 2014, MNRAS 444, 606. → Ch 9, Ch 39.
Andrew Chael — @achael: eht-imaging. Paper: Chael et al. 2018, ApJ 857, 23. → Ch 19.
Danny C. Price — @telegraphic: lead author of blimpy. Paper: Price et al. 2019, JOSS 4, 1554. → Ch 21.
Adam Deller — @adamdeller: creator of the DiFX software correlator (VLBA/LBA/EVN). Paper: Deller et al. 2007, PASP 119, 318. → Ch 19.
Ewan Barr — @ewanbarr: peasoup (GPU pulsar search) & sigpyproc. → Ch 13, Ch 18.
Vincent Morello — @v-morello: riptide (FFA) & clfd. Paper: Morello et al. 2020, MNRAS 497, 4654. → Ch 13, Ch 39.
Devansh Agarwal — @devanshkv: FETCH (FRB deep-learning classifier). Paper: Agarwal et al. 2020, MNRAS 497, 1661. → Ch 18, Ch 38.
Casey Law — @caseyjlaw: realfast / rfpipe (VLA fast-transient search). Paper: Law et al. 2018, ApJS 236, 8. → Ch 18.
Kiyoshi Masui — @kiyo-masui: burst_search & bitshuffle (CHIME). Paper: Masui et al. 2015, Nature 528, 523. → Ch 18.
Cees Bassa — @cbassa: cdmt (GPU coherent dedispersion). Paper: Bassa et al. 2017. → Ch 13.
Apostolos Spanakis-Misirlis — @0xCoto: VIRGO & PICTOR. Paper: Spanakis-Misirlis 2021, JOSS 6, 3067. → Ch 29.

Beyond GitHub (GitLab, SourceForge, Bitbucket)¶

Several cornerstone tools are not primarily on GitHub — listed here so the map is complete.

CASA (Common Astronomy Software Applications) — distributed as pip wheels (pip install casatools casatasks); there is no public GitHub monorepo. The open layer is casacore (above). Paper: CASA Team 2022, PASP 134, 114501. → Ch 12.
WSClean — gitlab.com/aroffringa/wsclean. The dominant wide-field imager. Paper: Offringa et al. 2014, MNRAS 444, 606.
AOFlagger — gitlab.com/aroffringa/aoflagger. The standard SumThreshold RFI flagger. Paper: Offringa et al. 2010, MNRAS 405, 155. → Ch 39.
RASCIL — gitlab.com/ska-telescope/external/rascil-main. The SKA's reference imaging library.
SatNOGS — gitlab.com/librespacefoundation/satnogs. The open global network of satellite ground stations. → Projects.
PSRCHIVE — psrchive.sourceforge.net. Pulsar archive analysis & the PSRFITS standard. Paper: Hotan, van Straten & Manchester 2004, PASA 21, 302.
DSPSR — dspsr.sourceforge.net (active GitHub mirror: rossjjennings/dspsr). Coherent dedispersion & folding. Paper: van Straten & Bailes 2011, PASA 28, 1.
heimdall — sourceforge.net/projects/heimdall-astro. GPU single-pulse search.
GILDAS / CLASS (IRAM) — iram.fr/IRAMFR/GILDAS. Single-dish & mm-interferometry spectral-line reduction.
HEALPix (C++/Fortran/IDL) — sourceforge.net/projects/healpix. The reference sphere-pixelisation library (healpy is its Python interface). Paper: Górski et al. 2005, ApJ 622, 759.

This catalogue is curated, not exhaustive — the radio-astronomy software ecosystem is large and moving. For the organisations and archives behind these tools see Resources; for the hardware and amateur builds that run them see Projects, Kits & Hacks; for the instruments see Radio Telescopes; for the underlying science see the Bibliography.