---
title: "ULAS J1342+0928"
url: "https://spacecatalog.org/object/ulas-j1342-0928"
release: "DR1"
licence: "CC-BY-4.0"
citation: "SpaceCatalog. ULAS J1342+0928 [catalogue entry]. Data release DR1 (2026-08-21). https://spacecatalog.org/object/ulas-j1342-0928"
---

# ULAS J1342+0928

ULAS J1342+0928 is a quasar in the constellation [Boötes](https://spacecatalog.org/constellation/bootes), 241.1 Gly from Earth. Its mass is 7.8×10⁸ M☉. It was discovered in 2017.

The most distant quasar known between 2017 and 2021. Its value is what sits in front of it: the hydrogen between the [galaxies](https://spacecatalog.org/galaxies) is still substantially neutral along this line of sight, which dates the era when starlight was still clearing the fog.

## At a glance

- **WHAT IT IS:** Quasar
- **HOW FAR:** 241.1 Gly — A luminosity distance, from its redshift — how faint it looks. The light itself left 12.6 billion years ago.
- **WHERE TO LOOK:** [Boötes](https://spacecatalog.org/constellation/bootes) — The patch of sky it sits in, as seen from Earth.

## Properties

| Quantity | Value |
| --- | --- |
| CLASS | Quasar |
| MASS | 7.8×10⁸ M☉ |
| DISTANCE FROM EARTH | 241.1 Gly — by luminosity distance from a published redshift, flat ΛCDM with H0 = 70 km/s/Mpc |
| CONSTELLATION | Boötes |
| RIGHT ASCENSION (J2000) | 13h 42m 08.1s |
| DECLINATION (J2000) | +09° 28′ 38.4″ |
| DISCOVERED | 2017 |

## Catalogue data

### WHAT KIND OF THING IT IS

What the object is in itself, rather than how it happens to look from here.

| Field | Value |
| --- | --- |
| Accretion state | quasar — a thin disc near its Eddington limit |
| Mass | 7.8×10⁸ M☉ |

### 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.

| Field | Value |
| --- | --- |
| Redshift (z) | 7.5413 |

## Also known as

- Common name: ULAS J1342+0928

## Source

[SpaceCatalog curated data](https://spacecatalog.org/releases) — CC-BY-4.0

How this was made: https://spacecatalog.org/methods#source-curated

## Cite this page

SpaceCatalog. ULAS J1342+0928 \[catalogue entry\]. Data release DR1 (2026-08-21). https://spacecatalog.org/object/ulas-j1342-0928

```bibtex
@misc{spacecatalog_ulas-j1342-0928,
  author       = {{SpaceCatalog}},
  title        = {{ULAS J1342+0928}},
  howpublished = {SpaceCatalog, data release DR1 (2026-08-21)},
  year         = {2026},
  url          = {https://spacecatalog.org/object/ulas-j1342-0928},
  note         = {Catalogue entry, data release DR1 (2026-08-21). Values from SpaceCatalog curated data.}
}
```

SpaceCatalog curated data — CC-BY-4.0

The page itself, with its pictures, the sky map and the observing tools: https://spacecatalog.org/object/ulas-j1342-0928