ATLAS Solar System Catalog V1

L. Denneau, J. L. Tonry, A. Heinze, R. Siverd, H. Weiland, A. Lawrence

Since 2017 the Hawaii-based ATLAS near-Earth asteroid (NEA) detection system[1] has monitored the entire dark sky from the north celestial pole to declination -50 every two nights to a dark-time sensitivity of V=19.7. In 2022, two additional ATLAS telescopes were installed in the southern hemisphere, allowing the system to monitor the entire dark sky from north to south celestial poles nearly every night. The uniform ATLAS all-sky survey has serendipitously detected over 500,000 different solar system objects, of which there are 150,000 asteroids and 179 comets with over 250 ATLAS observations spanning a wide range of observing geometry. The multi-band high-quality ATLAS photometry and accurate observation timing allow for shape modeling via folded lightcurves and subsequent taxomonic discrimination for a great number of these asteroids. All ATLAS calibrated exposures are maintained on disk, enabling on-demand forced photometry or stacking of historical observations to search for signatures of cometary or disruption activity. We present the initial release of the ATLAS solar system photometry catalog: a collection of serendipitous observations of solar system objects from ATLAS NEA survey operations, positionally matched to ephemerides, and measured against the ATLAS Refcat[2] photometric reference standard.

This document describes the first public release of the ATLAS Solar System Catalog (SSCAT), version 1. The catalog is built by cross-matching sources from the reduced images found by the dophot[3] program against per-exposure ephemerides of the entire MPC asteroid catalog computed by OpenOrb[4]. The nearest detection within a 10-arcsecond radius from a predicted position is then labeled with the asteroid name. All matches from all exposures are compiled into a single table, described below.

The SSCAT catalog can be obtained here.

While ATLAS normally finds sources from subtracted images in its NEO search, dophot executed against ATLAS unsubtracted images provides more accurate photometry for stellar PSFs, especially in crowded fields. Therefore for this catalog, which consists mainly of main-belt asteroids which will always have sky-plane motions small enough to match a stellar PSF, dophot is a reasonable choise.

To obtain "postage stamp" imagery for observations, we refer the user to the ATLAS Forced Photometry Server at fallingstar-data.com

At the time of catalog generation, the ATLAS sites in the southern hemisphere were still in comissioning and therefore no data from these telescopes is included in SSCAT V1. The next release will contain data from these telescopes.


This catalog consists of a space-delimited file containing the following columns:

MJD : exposure midpoint time, corrected for light travel time [MJD-UTC]

H : reduced absolute magnitude in ATLAS filter corrected to 1AU illumination, 1AU distance [AB]. H is computed using the HG system, with G=0.15; see [5].

dm : magnitude uncertainty from ATLAS [AB]

filt : ATLAS passband filter [1 char, 'o' or 'c'], see [1]

m : ATLAS magnitude [AB]

V : predicted V magnitude [Johnson]

m1AU : V mag at 1AU/1AU delta and R [Johnson]

delta : distance to asteroid from observer [AU]

R : distance to asteroid from Sun [AU]

SOE : Sun-Object-Earth angle [deg]

phi0 : standard phi0 parameter for G=0.15 (ref), see [5,6]

phi1 : standard phi1 parameter for G=0.15 (ref), see [5,6]

x : x position in observation [pix]

y : y position in observation [pix]

obs : ATLAS observation name

desig : MPC packed designation, see [7]

dx : x offset between kastx prediction and observed position [pix]

dy : y offset between kastx prediction and observed position [pix]


atlas-sscat.v1.0.dat.gz - gzipped atlas-sscat.v1.0.dat catalog

README.md - this file


The matching process is suitable for asteroids with well-known orbits, e.g. numbered and multiopposition asteroids in the MPC catalog. Dophot measures sources with stellar PSFs, so for nearby objects that may be trailed, or for bright comets, the results may be poor.

A very small number of observations have nonsensical object names that were mangled in an earlier version of this dataset and should be ignored. These will be removed in a subsequent release of the catalog.


[1] Tonry, J. L., “ATLAS: A High-cadence All-sky Survey System”, Publications of the Astronomical Society of the Pacific, vol. 130, no. 988, p. 064505, 2018. doi:10.1088/1538-3873/aabadf

[2] Tonry, J. L., “The ATLAS All-Sky Stellar Reference Catalog”, The Astrophysical Journal, vol. 867, no. 2, 2018. doi:10.3847/1538-4357/aae386

[3] Schechter, P. L., Mateo, M., and Saha, A., “DoPHOT, A CCD Photometry Program: Description and Tests”, Publications of the Astronomical Society of the Pacific, vol. 105, p. 1342, 1993. doi:10.1086/133316

[4] Granvik, M., Virtanen, J., Oszkiewicz, D., and Muinonen, K., “OpenOrb: Open-source asteroid orbit computation software”, Astrophysics Source Code Library, 2015. ascl:1502.002

[5] Bowell, E., Hapke, B., Domingue, D., Lumme, K., Peltoniemi, J., and Harris, A. W., “Application of photometric models to asteroids.”, in Asteroids II, 1989, pp. 524–556.

[6] Muinonen, K., “A three-parameter magnitude phase function for asteroids”, Icarus, vol. 209, no. 2, pp. 542–555, 2010. doi:10.1016/j.icarus.2010.04.003

[7] MPC Packed Provisional and Permanent Designations


If you use data from SSCAT, please acknowledge ATLAS using the text below:

This work uses data from the University of Hawaii's ATLAS project, funded through NASA grants NN12AR55G, 80NSSC18K0284, and 80NSSC18K1575, with contributions from the Queen's University Belfast, STScI, the South African Astronomical Observatory, and the Millennium Institute of Astrophysics, Chile.


This work has made use of data from the Asteroid Terrestrial-impact Last Alert System (ATLAS) project. ATLAS is primarily funded to search for near earth asteroids through NASA grants NN12AR55G, 80NSSC18K0284, and 80NSSC18K1575; byproducts of the NEO search include images and catalogs from the survey area. The ATLAS science products have been made possible through the contributions of the University of Hawaii Institute for Astronomy, the Queen's University Belfast, the Space Telescope Science Institute, the South African Astronomical Observatory (SAAO), and the Millennium Institute of Astrophysics (MAS), Chile.


ATLAS Project University of Hawaii info@fallingstar.com https://fallingstar.com