Mission Overview

A PSF-Based Approach to TESS High Quality Data Of Stellar Clusters (PATHOS)


Primary Investigator: Domenico Nardiello

HLSP Authors: Domenico Nardiello

Released: 2019-10-09

Updated: 2020-05-26

Primary Reference(s): Nardiello et al. 2019

DOI: 10.17909/t9-es7m-vw14

Citations: See ADS Statistics

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Logo credits: Viviana Taranto (taranto.viviana8@gmail.com)


The PATHOS project provides a database of high-precision light curves for members of stellar clusters, obtained by extracting photometry from TESS Full Frame Images. Light curves are obtained with an innovative PSF-based approach, that involves the use of empirical Point Spread Functions (PSFs), a high-angular resolution input catalogue (Gaia DR2) and neighbor-subtraction. The PSF-based approach minimises the dilution effects in crowded environments, enabling extraction of high-precision photometry for stars in the faint regime (T > 13).  The PATHOS database contains all the light curves extracted during the project, as well as light curves requested for other projects. Light curves of specific targets can be requested by contacting the project managers.

Data Release 1 (2019-10-09)
The PATHOS DR1 contains light curves of 16277 stars located in the dense region centered on the globular cluster 47 Tuc and observed by TESS in Sector 1. The catalog of the stars is described in Nardiello et al. (2019).

Data Release 2 (2020-05-27)
The PATHOS DR2 contains 219256 light curves of 162901 stars located in 645 open clusters located in the southern ecliptic hemisphere and observed by TESS in Sectors 1-13. The list of stars is based on the catalog by Cantat-Gaudin et al. (2018), a list of cluster members whose membership probabilities are calculated by using Gaia DR2 proper motions and parallaxes.

Data Products

Each target has a FITS and TXT version of the light curves available.  The files are stored in sub-directories based on the Sector they are in as a 4-digit, zero-padded number, e.g., "s0001/" for Sector 1.  The data file naming convention is:



  • <ticid> = The 10-digit, zero-padded TIC ID of the target
  • <sector> = The Sector number as a 4-digit, zero-padded value, e.g., "s0001" for Sector 1
  • <ext> = The data file type extension

Data file types:

_llc.fits The light curve file in FITS format.
_llc.txt The light curve file in TEXT format.


The available columns include the raw fluxes from the PSF-based approach and four different aperture sizes (PSF_FLUX_RAW, AP{1,2,3,4}_FLUX_RAW) and the corrected fluxes (PSF_FLUX_COR, AP{1,2,3,4}_FLUX_COR).  The TIME column is in barycentric-corrected, truncated TESS Julian Date (BJD - 2457000.0).

Data Access

PATHOS data products are available in the MAST Portal and astroquery.mast.  For those who want to download all the light curves for a given Sector, the following Python code example below will query for all the available PATHOS observations for a given Sector (should take a few minutes) and then download the light curve FITS files.  NOTE: There are tens of thousands of light curves for a given Sector, thus downloading all of the products can take the better part of a day, even with good internet connections.  By default, the light curve files will be downloaded under a folder called "mastDownload" in the same working directory that your run the Python script from.

from astroquery.mast import Observations
sector_num = '1'
print('Querying for PATHOS Sector ' + sector_num + " Observations...")
obsTable = Observations.query_criteria(provenance_name = "PATHOS",
                                       sequence_number = sector_num)
print("Found a total of " + str(len(obsTable)) + " PATHOS targets.")
print('Downloading data products for these observations...')
for obs in obsTable:
    data_products = Observations.get_product_list(obs)
Link to the MAST Portal Webpage

MAST Portal

A web-based interface for cross-mission searches of data at MAST or the Virtual Observatory. Download PATHOS light curves for a few targets.
Link to MAST Astroquery

MAST Astroquery

Search for, and retrieve, PATHOS data products programmatically based on a list of coordinates or target names.


Please remember to cite the appropriate paper(s) below and the DOI if you use these data in a published work. 

Note: These HLSP data products are licensed for use under CC BY 4.0.