---
title: "NGC 6491"
url: "https://spacecatalog.org/object/ngc-6491"
release: "DR1"
licence: "CC-BY-SA-4.0"
citation: "SpaceCatalog. NGC 6491 [catalogue entry]. Data release DR1 (2026-08-21). https://spacecatalog.org/object/ngc-6491"
---

# NGC 6491

NGC 6491 is a spiral [galaxy](https://spacecatalog.org/galaxies) Sab in the constellation [Draco](https://spacecatalog.org/constellation/draco), 290.6 Mly from Earth, shining at apparent magnitude 14.43 (B). Other catalogues list it as 2MASX J17500071+6131542, IRAS 17494+6132 and IRAS F17494+6132, among 11 designations in total. It was discovered in 1885.

## At a glance

- **WHAT IT IS:** Spiral galaxy
- **HOW FAR:** 290.6 Mly — A luminosity distance, from its redshift — how faint it looks. The light itself left 285 million years ago.
- **HOW BIG ON THE SKY:** 1.3′ — Small enough that the full Moon would cover it several times over.
- **HOW BRIGHT (B):** 14.43 — Faint: it takes a large telescope.
- **WHERE TO LOOK:** [Draco](https://spacecatalog.org/constellation/draco) — The patch of sky it sits in, as seen from Earth.

## Properties

| Quantity | Value |
| --- | --- |
| CLASS | Spiral galaxy Sab |
| DISTANCE FROM EARTH | 290.6 Mly ±18 — by redshift (CMB frame), flat ΛCDM with H0 = 70 km/s/Mpc |
| APPARENT MAGNITUDE (B) | 14.43 |
| CONSTELLATION | Draco |
| RIGHT ASCENSION (J2000) | 17h 50m 00.7s |
| DECLINATION (J2000) | +61° 31′ 54.4″ |
| DISCOVERED | 1885 |

## 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 |
| --- | --- |
| Hubble type | Sab |

### HOW BRIGHT IT IS

What the light adds up to, measured through one filter at a time. A magnitude is a brightness on a backwards scale — the smaller the number, the brighter the object.

| Field | Value |
| --- | --- |
| Apparent magnitude (B) | 14.43 |
| Apparent magnitude (J) | 11.29 |
| Apparent magnitude (H band) | 10.58 |
| Apparent magnitude (K) | 10.24 |
| Surface brightness | 23.26 mag/arcsec² |

### 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 |
| --- | --- |
| Radial velocity | 6148 km/s |
| Redshift (z) | 0.02072 |
| Redshift (z, CMB frame) | 0.0204872 |
| Major axis | 1.25′ |
| Minor axis | 0.46′ |
| Position angle | 37° |

### WHEN IT WAS FOUND

Who first saw it, from where, and by what method.

| Field | Value |
| --- | --- |
| Discovered by | Lewis A. Swift |

### OTHER NAMES AND NUMBERS

The identifiers other catalogues file this object under, for anyone joining this data to theirs.

| Field | Value |
| --- | --- |
| OpenNGC type code | G |
| Wikidata item | Q1146116 |

## Also known as

- 2MASX: 2MASX J17500071+6131542
- IRAS: IRAS 17494+6132
- IRAS: IRAS F17494+6132
- LEDA: LEDA 60948
- LEDA: LEDA 60949
- MCG: MCG +10-25-103
- NGC: NGC 6491
- NGC: NGC 6493A
- PGC: PGC 60948
- PGC: PGC 60949
- UGC: UGC 11008

## Source

[OpenNGC](https://github.com/mattiaverga/OpenNGC) — CC-BY-SA-4.0

The producer asks: OpenNGC, Mattia Verga (github.com/mattiaverga/OpenNGC). Fields derived from it stay under CC BY-SA 4.0.

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

## Cite this page

SpaceCatalog. NGC 6491 \[catalogue entry\]. Data release DR1 (2026-08-21). https://spacecatalog.org/object/ngc-6491

```bibtex
@misc{spacecatalog_ngc-6491,
  author       = {{SpaceCatalog}},
  title        = {{NGC 6491}},
  howpublished = {SpaceCatalog, data release DR1 (2026-08-21)},
  year         = {2026},
  url          = {https://spacecatalog.org/object/ngc-6491},
  note         = {Catalogue entry, data release DR1 (2026-08-21). Values from OpenNGC.}
}
```

OpenNGC — CC-BY-SA-4.0

Acknowledgement the producer asks for: OpenNGC, Mattia Verga (github.com/mattiaverga/OpenNGC). Fields derived from it stay under CC BY-SA 4.0.

The page itself, with its pictures, the sky map and the observing tools: https://spacecatalog.org/object/ngc-6491