A Dataset Designed to Train and Test Very Long Baseline Interferometry Image Reconstruction Algorithms

- What are the website's features?
- How do I generate my own data?
- What are the data formats and how do I use them?
- Why does the data generation forum produce an error when I submit?
- Who should I contact if I have questions?

The primary data format that we have chosen to use is OIFITS. OIFITS is a standard for exchanging data for Optical (Visible/IR) Interferometry, and is based on the FITS Standard. Since mm/sub-mm VLBI shares a lot of similarities to optical interferometry, this format is better suited for mm/sub-mm measurements than UVFITS. More information on the OIFITS format can be found here. We list the variables described in this paper in the tables below.

We provide a number of tools that may be useful in reading and writting in the OIFITS format:

- Paul Boley has written a OIFITS Python module that you can download here
- Python code that can be used to write an OIFITS file from an output MAPS text file can be downloaded here
- Python code by Andrew Chael to extract information from OIFITS and write it to a text file can be downloaded here

OI_T3 Variables |
Description |
Units |

T3AMP | Triple-product/Bispectrum amplitude | Jansky^{3} |

T3PHI | Triple-product phase | Degrees |

T3AMPERR | Standard deviation of error in triple product amplitude | Jansky^{3} |

T3PHIERR | Standard deviation of error in phase | Degrees |

U1COORD | u coordinate of baseline AB of the triangle | meters |

U2COORD | u coordinate of baseline BC of the triangle | meters |

V1COORD | v coordinate of baseline AB of the triangle | meters |

V2COORD | v coordinate of baseline BC of the triangle | meters |

STA_INDEX | Station numbers contributing to the data | |

INT_TIME | Integration time | seconds |

MJD | Modified Julian Date | |

TIME | UTC time of observation | seconds |

OI_VIS2 Variables |
Description |
Units |

VIS2DATA | Squared visibility | Jansky^{2} |

VIS2ERR | Standard deviation of error in squared visibility | Jansky^{2} |

UCOORD | u coordinate of baseline | meters |

VCOORD | v coordinate of baseline | meters |

STA_INDEX | Station numbers contributing to the data | |

INT_TIME | Integration time | seconds |

MJD | Modified Julian Date | |

TIME | UTC time of observation | seconds |

OI_VIS Variables |
Description |
Units |

VISAMP | Squared visibility | Jansky |

VISPHI | Visibility phase | Degrees |

VIS2ERR | Standard deviation of error in squared visibility | Jansky |

VISPHIERR | Error in visibility phase in degrees | Degrees |

UCOORD | u coordinate of baseline | meters |

VCOORD | v coordinate of baseline | meters |

STA_INDEX | Station numbers contributing to the data | |

INT_TIME | Integration time | seconds |

MJD | Modified Julian Date | |

TIME | UTC time of observation | seconds |

OI_WAVELENGTH Variables |
Description |
Units |

EFF_WAVE | Effective wavelength of channel | meters |

EFF_BAND | Effective bandpass of channel | meters |

OI_ARRAY Variables |
Description |
Units |

TEL_NAME/STA_NAME | Station name | |

STA_INDEX | Station number | |

DIAMETER | Element diameter | meters |

We have also included the data in MATLAB's MAT-file format. The MAT-file stores workspace variables that can be easily loaded into MATLAB or Octave. Due to the ease of loading and viewing the data in the MAT format, this can be helpful for verifying that you are reading the OIFITS data correctly.

Bispectrum Variables |
Description |
Units |

t3amp | Triple-product/Bispectrum amplitude | Jansky^{3} |

t3phi | Triple-product phase | Degrees |

t3amperr | Standard deviation of error in triple product amplitude | Jansky^{3} |

t3phierr | Standard deviation of error in phase | Degrees |

uClosure | u coordinate of baseline AB of the triangle | wavelengths |

vClosure | v coordinate of baseline AB of the triangle | wavelengths |

antOrder | Station numbers contributing to the data | |

mjdClosure | Modified Julian Date | |

Visiility Variables |
Description |
Units |

amp | Triple-product/Bispectrum amplitude | Jansky |

phase | Triple-product phase | Degrees |

viserror | Standard deviation of error in triple product amplitude | Jansky |

u | u coordinate of baseline | wavelengths |

v | v coordinate of baseline | wavelengths |

ant1 | Station number 1 contributing to the data | |

ant2 | Station number 2 contributing to the data | |

mjd | Modified Julian Date | |

Miscellaneous Variables |
Description |
Units |

frequency | Effective frequency of channel | Hertz |

bandWidth | Effective bandwidth of channel | Hertz |

intTime | Integration time | seconds |

RACent | Right Ascension | Degrees |

DECCent | Declination | Degrees |