---
title: "PKS 0637-752"
url: "https://spacecatalog.org/object/pks-0637-752"
release: "DR1"
licence: "CC-BY-4.0"
citation: "SpaceCatalog. PKS 0637-752 [catalogue entry]. Data release DR1 (2026-08-21). https://spacecatalog.org/object/pks-0637-752"
---

# PKS 0637-752

PKS 0637-752 is a quasar in the constellation [Mensa](https://spacecatalog.org/constellation/mensa), 12.71 Gly from Earth.

Chandra's first target after launch, picked as a calibration source because it was expected to be a plain point. It was not: the image showed an X-ray jet 800,000 light-years long, and the discovery came out of an exposure taken to check the focus.

## At a glance

- **WHAT IT IS:** Quasar
- **HOW FAR:** 12.71 Gly — A luminosity distance, from its redshift — how faint it looks. The light itself left 6.00 billion years ago.
- **WHERE TO LOOK:** [Mensa](https://spacecatalog.org/constellation/mensa) — The patch of sky it sits in, as seen from Earth.

## Properties

| Quantity | Value |
| --- | --- |
| CLASS | Quasar |
| DISTANCE FROM EARTH | 12.71 Gly — by luminosity distance from a published redshift, flat ΛCDM with H0 = 70 km/s/Mpc |
| CONSTELLATION | Mensa |
| RIGHT ASCENSION (J2000) | 06h 35m 46.5s |
| DECLINATION (J2000) | −75° 16′ 16.8″ |

## 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 |

### 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) | 0.65420709 |

## Also known as

- Common name: PKS 0637-752

## 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. PKS 0637-752 \[catalogue entry\]. Data release DR1 (2026-08-21). https://spacecatalog.org/object/pks-0637-752

```bibtex
@misc{spacecatalog_pks-0637-752,
  author       = {{SpaceCatalog}},
  title        = {{PKS 0637-752}},
  howpublished = {SpaceCatalog, data release DR1 (2026-08-21)},
  year         = {2026},
  url          = {https://spacecatalog.org/object/pks-0637-752},
  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/pks-0637-752