DECam Asteroid Database (DAD)

The DECam Asteroid Database contains a list of candidate asteroids (moving objects) from archival Dark Energy Camera (DECam) images.

The DECam NEO Survey (P.I. Lori Allen) used DECam to measure the size distribution of Near-Earth Objects (NEOs) from 1 km to 10 m. The survey has measured 235 unique NEOs, implying the existence of 4 million NEOs larger than 10 m (Allen 2016). For more information on the NEO survey, see the presentation from the 2015 "Science with DECam meeting".

Database Tables

The fundamental organization and linkage between tables is the dataset. A dataset is a pointing on the sky from which multiple exposures were used to search for asteroid tracklets. This field is common to all tables and is a primary key for joining.
 The database is organized around tracklets. A tracklet is some number of measurements from individual exposures that are identified as moving in the field and are celestial sources (i.e. not junk). A tracklet has an identification (movid) which is uniquely derived from the exposure and detection number (groupid). When known, tracklets will have IDs from the Minor Planet Center (mpcid) which may then link multiple tracklets from different nights.
 The first data release was only for the DECam NEO Survey (P.I. Allen). The second release supersedes the first release, and added tracklets derived from all public DECam data that are suitable for the Moving Object Detection System (MODS) algorithm (Valdes et al. 2017). This version is still an early release with some database records having incomplete fields. Both releases of objects and measurements are available through Data Lab. The database and list of tables can be browsed using Data Lab's table browser.
 The following is a brief overview of the logical organization of the entities that make up the database tables. A dataset consists of a number of exposures (> 2). An exposure is characterized by an exposure ID (a filename) and parameters of the exposure such as time and length of the exposure. A group is a set of observations of an object in some or all of the exposures identified as forming a moving object tracklet. A tracklet is characterized by an ID and parameters such as the rate of motion and magnitude. An observation is an individual detection of a moving object in a CCD of an exposure. It is characterized by positions in three coordinate systems (equitorial on the sky, CCD image pixel, and cutout image pixel). A filename for a cutout image is also given. Related is a table giving the MPC formated record for the observation. The set of records for a particular tracklet is what was submitted as a detection to the MPC.

DAD DR2 Table Information
Table Name Row Count Total Exposures Total Tracklets
DAD DR1 Table Information
Table Name Row Count Total Exposures Total Tracklets


This table describes the characteristics of the datasets (pointings). The time and position fields are for the start of the first observation exposure in the set. Position fields are for the center of the field. See the MOVDS table for column names, descriptions, and datatypes.


The exposure table provides details of each exposure. The expname is a way to link to the image data in the Astro Data Archive. The expid is the sequential count of the exposures in a dataset. The separation time is a relative time for the middle of each exposure with an origin at the start of the first exposure. See the MOVEXP table for column names, descriptions, and datatypes.


This is the main tracklet table. It provides information about each connected set of observations corresponding to a moving object. See the MOVGRP table for column names, descriptions, and datatypes.


These tables provide information for each separate detection of a moving object. They provide links to associated files (see below) and to what was reported to the MPC. (The MPC records are sometimes the only way to find information from the MPC website). Note that the MPC records are basically an encoding of the information in the exposure and observation tables in a specific format for reporting the time, position, and estimated magnitude for an observation. See the MOVOBS table for column names, descriptions, and datatypes. See the MOVMPC table for column names, descriptions, and datatypes.

Data Products

At this time, Astro Data Lab only provides the DAD DR1 and DAD DR2 catalog tables.

Survey Statistics

DAD DR2 Basic Statistics
P.I. Pointings Tracklets
Allen 3,126 608,829
Sheppard 924 46,833
Forster 220 3,353
Fuentes 280 1,267
Dell_Antonio 28 433
Munoz 84 270
French 138 185
Carlin 37 140
Vivas 39 120
Rich 12 108
Sullivan 35 73
Saha 46 62
Trilling 47 59
Yip 12 46
Frieman 38 39
Geha 18 39
Dai 23 35
Rest 24 35
Bonaca 13 32
Mamajek 44 30
Heinze 3 27
Crnojevic 15 22
Konstantopoulos 4 21
Hargis 3 18
Mackey 20 16
Taylor 21 16
McMonigal 16 10
Calamida 4 7
Walker 5 7
Sheen 1 6
Briceno 12 3
Curtin 2 2
McCleary 7 2
Penny 2 2
Rusu 1 2
Silva 1 2
Geisler 1 1
Schlegel 1 1
Yan 3 1
DAD DR1 Basic Statistics
P.I. Pointings Tracklets
Allen 3,126 608,829
Sheppard 366 46,345
Forster 220 3,730
Fuentes 132 1,088
Rich 9 89
Sullivan 33 72
Saha 24 53
Geha 9 39
Frieman 32 37
Dai 23 35
Heinze 3 27
Bonaca 3 25
Rest 15 24
Konstantopoulos 4 21
Walker 4 21
Hargis 3 18
Taylor 21 16
Mackey 9 15
Munoz 10 14
Crnojevic 9 13
McMonigal 6 10
Sheen 1 6
Calamida 2 4
McCleary 2 3
Rusu 1 2
Geisler 1 1
Mamajek 1 1
Vivas 1 1