Precovery

Find past observations of asteroids and comets in archived survey data. Precovery propagates each object's orbit and uncertainty across a selected date range, identifies exposures that could contain it, and returns candidate detections with review diagnostics, available image products, and current MPC and Scout context.

Run Precovery

How it works

Precovery starts from an orbit and covariance obtained from JPL SBDB, ESA NEOCC, JPL Scout, or the Minor Planet Center. For each object, it propagates that state across the selected date range, predicts an uncertainty region on the sky at each epoch, and intersects the region with archived survey exposure footprints. It searches available detections in matching exposures, evaluates positional consistency and, when supported, magnitude criteria, then presents the rows with current MPC attribution and NEOCP or Scout context.

Searches run asynchronously. The result page reports progress and displays queryable results as they become available. See the Precovery methods page for the propagation, frame-selection, and detection-acceptance model.

Candidate rows require expert review and should not be submitted automatically to the Minor Planet Center.

What a Precovery result contains

Each result reports how many target-attributed observations were recovered, which candidate detections were found, and the evidence available for reviewing each row.

Observation accounting

Counts distinguish recovered target-attributed rows, searched rows that were not recovered, pending states, and rows outside the selected search window.

Candidate review

Rows include survey, observatory, time, search status, astrometric residuals, innovation distance, magnitude, MPC attribution, and NEOCP or Scout state.

Images, provenance, and exports

Available image products show measured and predicted positions. Orbit provenance, ADES PSV exports, and adam-core SourceCatalog exports support independent review and follow-up analysis.

Example results from real searches

Browse read-only Precovery results for 3 real objects. No account is required. Each page shows recovered attributed observations, candidate detections, row-level diagnostics, and available survey images in the Precovery result interface.

(2026 QH)

Eight accepted ATLAS candidate rows. Precovery recovered 104 of 109 target-attributed rows in the search window.

8 rows in New Candidates
104 of 109 attributed rows recovered
Difference and reference images for all 8 candidate rows

(2026 PG)

Four accepted Rubin candidate rows from one night. Precovery recovered all 21 target-attributed rows.

4 rows in New Candidates
21 of 21 attributed rows recovered
Rubin difference, template, and science images for all 4 candidate rows

(2026 QC)

No candidate rows. Precovery recovered all 35 target-attributed rows and reports the empty candidate set explicitly.

0 rows in New Candidates
35 of 35 attributed rows recovered
35 attributed rows checked

View all example results

Inputs and orbit sources

One or more asteroid or comet designations per search
A start and end date within supported SPICE coverage
All currently available survey datasets and mapped observatories are searched; coverage varies by source and date

Available orbit sources

JPL Small-Body Database (SBDB)
ESA Near-Earth Object Coordination Centre (NEOCC)
JPL Scout
Minor Planet Center (MPC)

Search dates can range from 1962-01-20 through 2099-08-27. The catalog window begins on 2012-09-01; the earliest survey detections in the current inventory are NSC observations from 2012-09-23.

Interpretation limits

Expert review is required before candidate observations are submitted to the Minor Planet Center.
Image peak and background values are image-quality diagnostics, not calibrated detection significance.
Propagation is gravity-only; non-gravitational forces such as comet outgassing or strong Yarkovsky acceleration are not modeled.
Predicted magnitudes use an H/G model when the required input is available. Comet and active-object brightness is not predicted, so magnitude filtering can exclude real detections for those objects.
Results depend on the input orbit and covariance, selected dates, and the survey coverage and detections available in the archive.

Search datasets and telescopes

The current image-search catalog contains five survey datasets across ten mapped MPC observatory codes. Published MPC astrometry is included as a sixth, non-image dataset.

ATLAS difference-image detections `atlas`

ATLAS survey telescopes at Mauna Loa (T08), Haleakalā (T05), South Africa (M22), and Chile (W68).

Catalog coverage: 2015-06-18 onward.

Zwicky Transient Facility alerts `ztf`

Samuel Oschin Telescope at Palomar Observatory (I41).

Catalog coverage: 2018-06-01 onward.

NOIRLab Source Catalog DR2 `nsc`

Blanco/DECam at CTIO (W84), Bok/90Prime (V00), and Mayall/Mosaic3 at Kitt Peak (695).

Catalog coverage: 2012-09-23 through 2019-11-16.

SkyMapper Southern Survey DR2 `skymapper`

SkyMapper telescope at Siding Spring Observatory (Q55).

Catalog coverage: 2014-03-15 through 2018-03-31.

Rubin Observatory / LSST alerts `lsst`

Simonyi Survey Telescope at Vera C. Rubin Observatory (X05).

Catalog coverage: default start 2025-09-01; continuing.

Minor Planet Center published observations `mpc`

Published astrometry from the worldwide MPC station network. This is a non-image reference dataset used for recovery and attribution accounting, not a single telescope archive.

See AIMS data provenance for source-specific access, selection, normalization, and limitations.

Search the archive for your object

Sign in to search for one or more asteroid or comet designations using an orbit from JPL SBDB, ESA NEOCC, JPL Scout, or the MPC.