SDSS J1148+5251
LENSED · SCHWARZSCHILD FROM 3×10⁹ M☉ · ACCRETION QUASAR · INCLINATION NOT MEASURED · DISC PEAK 48 600 K
OVERVIEW
] BLACK HOLESDSS J1148+5251 is a in the constellation Ursa Major, 202.2 from Earth. Its mass is 3×10⁹ . It was discovered in 2003.
The first quasar in the early universe found to contain carbon monoxide and dust. Both are made by stars, so a galaxy less than a billion years old had already been through enough generations of them to enrich its own gas.
- WHAT IT IS
- Quasar
- HOW FAR
- 202.2
A luminosity distance, from its redshift — how faint it looks. The light itself left 12.5 billion years ago.
THE MODEL
] LENSEDCALCULATED · NOT AN OBSERVATION · SCHWARZSCHILD RADIUS FROM THE MASS · 3×10⁹ M☉ · ACCRETION QUASAR · INCLINATION NOT MEASURED · DISC PEAK 48 600 K · SKY BENT AROUND THE HOLE
The black disc is the shadow, 2.6 times wider than the horizon that casts it, and every ray in the frame is a null geodesic of the Schwarzschild metric. The disc starts at the innermost stable circular orbit and its colour is a temperature computed from this object's own mass; one turn of its inner edge really takes 1 400 000 seconds. Drag it, or use the arrow keys, to look from another direction. The stars behind are the 498,631 this catalogue holds real distances for, drawn from where the camera actually is — but every one of them is within 170 parsecs of the Sun and this object is much further out, so from here that whole neighbourhood is a knot in one direction and the rest of the sky is empty. The view you land on looks the other way; turn back towards the Sun and the stars come with it. What the readout says is which of the two the frame is pointed at. The emptiness is not a missing backdrop — it is the edge of what this catalogue has measured. And they are not where they are. Light that passes a black hole is bent towards it, so every star behind this one is seen further from it than it stands: the ones almost directly behind swing out into a ring and brighten as they go, the sky immediately around the shadow is emptied to fill that ring, and part of the ring is light from stars behind you, carried round the far side. Turn the view and watch a star climb out of the middle rather than cross it. Each one is still a measured parallax — moved along the path the metric gives its light, and nothing else.
OBSERVING
] FROM WHERE YOU AREWhat it takes to see SDSS J1148+5251 for yourself. Everything in this part of the page is worked out for a real horizon, a real night and the equipment you say you have.
Say where you are, and this line says when SDSS J1148+5251 is worth going out for.
APPARENT PLACE
] EQUINOX J2026.7Where a telescope has to be pointed today, which is not quite where the catalogue records the object: the coordinate grid itself has turned since the year 2000 the catalogue is referred to.
- RIGHT ASCENSION
- DECLINATION
- GRID TURNED SINCE
- 15.7
- PROPER MOTION SINCE
- none published
Computed for 2026-09-04 00:00 UT. No proper motion is published for SDSS J1148+5251, so nothing here moves the object; what separates this from the catalogued position above is the coordinate grid turning under it — about fifty arcseconds a year of precession since 2000, and the small nodding of the Earth’s axis on top of that. Aberration and refraction are not included, and neither is parallax; each is under an arcminute, which is also about as well as the catalogued position is known. The same figure for any date.
CATALOG DATA
] 3 FIELDSThe raw catalogue values, as the source published them, with the error bars where one was published — sorted by what each set of figures is about rather than by the order they happened to be stored in.
WHAT KIND OF THING IT IS
What the object is in itself, rather than how it happens to look from here.
- Accretion state
- quasar — a thin disc near its Eddington limit
- Mass
- 3×10⁹
WHERE IT IS AND HOW IT MOVES
Position, motion across the sky and the size it covers on it. These are measurements of the object as seen from here, so every one of them depends on where here is.
- Redshift (z)
ALSO KNOWN AS
] 1 DESIGNATIONS- Common name SDSS J1148+5251
LOOK IT UP ELSEWHERE
] 1 SERVICEEach link carries the identifier printed beside it. Nothing on this page is a measurement of our own, so a number that disagrees with one of these is worth reporting — and a service that has never catalogued this object under this name will say so plainly.
- VizieR5″ around 177.0694 +52.8640
Every published table with a row at this position, searched by coordinates rather than by name.
CITE THIS PAGE
] DR1This page is live and its numbers move when an upstream refreshes, so the citation names the release the rows belong to rather than the day you read them. The release itself is frozen, republished as a bundle, and is what a data-availability statement should point at.
SpaceCatalog. SDSS J1148+5251 [catalogue entry]. Data release DR1 (2026-08-21). https://spacecatalog.org/object/sdss-j1148-5251
@misc{spacecatalog_sdss-j1148-5251,
author = {{SpaceCatalog}},
title = {{SDSS J1148+5251}},
howpublished = {SpaceCatalog, data release DR1 (2026-08-21)},
year = {2026},
url = {https://spacecatalog.org/object/sdss-j1148-5251},
note = {Catalogue entry, data release DR1 (2026-08-21). Values from SpaceCatalog curated data.}
}The values above were taken from SpaceCatalog curated data — CC-BY-4.0. Citing this page does not replace citing that catalogue.