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The Pleiades, the edited photograph that gives the Ulula measurements their context

(714) Ulula, from three exposures to the scale of Portugal

A 41-kilometre asteroid caught crossing the Pleiades field on 25 July 2026, measured in three solved frames, placed on its orbit and set down over the map

(714) Ulula is a known main-belt asteroid. On the night of 24 to 25 July 2026 it crossed the sensor while the telescope was on the Pleiades, and it was recovered in all three independently solved 30-second source frames that caught it. The edited Pleiades photograph is context; the measured positions come from those three timestamped, plate-solved exposures.

The edited Pleiades image with the three measured Ulula positions drawn at the lower edge
The whole edited frame, with the three source-frame positions projected onto it through a validated registration (513 inliers, 0.29 px rms) and drawn live: the diamond at the lower edge, and the rectangle the detail below was cut from. Hover the diamond for each frame's time.
Detail of the edited Pleiades image with the three Ulula source-frame positions
The unscaled detail, at native resolution: the three measured positions, projected from the solved frames onto the edited image.

Ulula's transformed position lies at the black bottom edge of the visible mosaic footprint. The marker remains there because moving it onto the brighter Pleiades field would be scientifically false. The markers project source-frame astrometry onto the edited stack. They do not establish that the asteroid is independently visible or measurable in the edited JPEG, and the edited image is not suitable for photometry.

Three discrete samples

The registered blink: measured position as an open diamond, predicted position as a dashed circle
The registered blink is a derivative comparison of three discrete samples, not continuous video. Open diamond: measured. Dashed circle: predicted.

The blink compares the three solved frames after registration. Three samples are enough to confirm a known object at its predicted place: the measured source stays within 1.2 arcseconds of the prediction. The measured motion over the 5.13 minute baseline is 1.09 arcseconds per minute at position angle 77.2°, against 0.93 at 83.6° predicted. Three samples are not an orbit determination and not submission-quality astrometry.

Ulula's predicted position on the night, at the Seestar frame's size, beside the Pleiades. Pinch to zoom; drag to turn.
A grainy grey star field headed Known asteroid (714) Ulula, three solved 30 s exposures, with an open diamond at the bottom edge
One of the three source exposures, star-matched to the edited image so the positions can be carried across.

The catalogue sweep

The full Pleiades-region query is dense because the mosaic lies near the ecliptic. SkyBoT returned 1,182 known objects in the broad search circle and 904 in the initial conservative circumscribed-frame envelopes. Those are catalogue predictions, not 904 detections.

Only three predicted objects were brighter than V=16:

  • (714) Ulula: verified in the actual sensor and detected.
  • (359) Georgia: five independently solved candidate frames place it outside the actual sensor rectangles.
  • (852) Wladilena: both candidate frames place it outside the actual sensor rectangles.

The prior long-linear-trail screen returned zero candidates. No additional uncatalogued moving-object candidate is claimed. A complete blind registered-subframe point-source tracklet search across the whole mosaic was not run, so this is not a definitive zero-result for unknown objects. Because the only measured mover matched Ulula, no targeted recent-survey archive query was needed.

The orbit at the observation epoch

Ulula on its JPL orbit at the observation epoch, 25 July 2026 03:56 UTC, with the planets from JPL DE440s at that moment and the 4,000-orbit belt sample: a biased catalogue sample, not a density map. Drag to turn; pinch to zoom.

The film's orbit graphic is fixed at the observation epoch; its line reveal in the film changes visibility only. It uses JPL SBDB elements with local two-body propagation for Ulula, a pinned JPL DE421 planetary ephemeris, and a biased systematic sample of 4,000 numbered main-belt objects. That sample is not a literal density or completeness map.

At the scale of Portugal

The Ulula model, a 41.343 ± 2.348 km effective diameter, over mainland Portugal at one kilometre scale; click it to fly to the model, the ground or Esc to come back, and drag to turn. Boundary from OpenStreetMap contributors (ODbL).

The rotating Ulula mesh is a scientific 3D model scaled to a sourced 41.343 ± 2.348 km effective-volume diameter. It is physical context, not resolved telescope imagery. Its placement over mainland Portugal is a same-scale size reference, not an impact location or prediction. Rotation in the film is time-compressed.

Films

Twenty-eight seconds: the Pleiades field, the three measured positions blinked, the orbit at the observation epoch, and the shape model over mainland Portugal at one scale.

Published from session ulula-instagram-reel-2026-07-25 · run 20260727T213401Z-publication-science-video; session user-edits-2026-07-25 · run 20260727T161745Z-ulula-edited-image-overlay; session m45-mosaic-2026-07-25-ircut-30s · run 20260726T125202Z-asteroid-search. Every number above traces to a sealed measurement in those runs.

A render of the Sun rising over the Earth's limb, seen from orbit, with city lights on the night side

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