PG 1302-102

BLACK HOLEQuasar

LENSED · SCHWARZSCHILD FROM ACCRETION QUASAR · INCLINATION NOT MEASURED

[

OVERVIEW

] BLACK HOLE

PG 1302-102 is a in the constellation Virgo, 4.633 from Earth.

Its brightness rises and falls on a cycle of about five years, which has been read as two black holes orbiting a few light-months apart. The reading is disputed — a warp in a single disc would do the same thing — and it is among the best candidates rather than a settled case.

WHAT IT IS
Quasar
HOW FAR
4.633

A luminosity distance, from its redshift — how faint it looks. The light itself left 3.21 billion years ago.

WHERE TO LOOK
Virgo

The patch of sky it sits in, as seen from Earth.

[

OBSERVING

] FROM WHERE YOU ARE

What it takes to see PG 1302-102 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.

TONIGHT

Say where you are, and this line says when PG 1302-102 is worth going out for.

[

APPARENT PLACE

] EQUINOX J2026.7

Where 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
22.5
PROPER MOTION SINCE
none published

Computed for 2026-09-03 00:00 UT. No proper motion is published for PG 1302-102, 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

] 2 FIELDS

The 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

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 PG 1302-102
[

LOOK IT UP ELSEWHERE

] 1 SERVICE

Each 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.

[

CITE THIS PAGE

] DR1

This 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.

PLAIN TEXT
SpaceCatalog. PG 1302-102 [catalogue entry]. Data release DR1 (2026-08-21). https://spacecatalog.org/object/pg-1302-102
BIBTEX
@misc{spacecatalog_pg-1302-102,
  author       = {{SpaceCatalog}},
  title        = {{PG 1302-102}},
  howpublished = {SpaceCatalog, data release DR1 (2026-08-21)},
  year         = {2026},
  url          = {https://spacecatalog.org/object/pg-1302-102},
  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.

[

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