---
title: "NGC 3991"
url: "https://spacecatalog.org/object/ngc-3991"
release: "DR1"
licence: "CC-BY-SA-4.0"
citation: "SpaceCatalog. NGC 3991 [catalogue entry]. Data release DR1 (2026-08-21). https://spacecatalog.org/object/ngc-3991"
---

# NGC 3991

NGC 3991 is a [galaxy](https://spacecatalog.org/galaxies) pair in the constellation [Ursa Major](https://spacecatalog.org/constellation/ursa-major). Other catalogues list it as IRAS 11549+3237, IRAS F11549+3236 and LEDA 37613, among 8 designations in total. It was discovered in 1864.

## At a glance

- **WHAT IT IS:** Galaxy pair
- **HOW BIG ON THE SKY:** 1.8′ — Small enough that the full Moon would cover it several times over.
- **WHERE TO LOOK:** [Ursa Major](https://spacecatalog.org/constellation/ursa-major) — The patch of sky it sits in, as seen from Earth.

## Properties

| Quantity | Value |
| --- | --- |
| CLASS | Galaxy pair |
| CONSTELLATION | Ursa Major |
| RIGHT ASCENSION (J2000) | 11h 57m 31.1s |
| DECLINATION (J2000) | +32° 20′ 16.0″ |
| DISCOVERED | 1864 |

## Catalogue data

### 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 |
| --- | --- |
| Major axis | 1.8′ |

### WHEN IT WAS FOUND

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

| Field | Value |
| --- | --- |
| Discovered by | Heinrich Louis d'Arrest |

### OTHER NAMES AND NUMBERS

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

| Field | Value |
| --- | --- |
| OpenNGC type code | GPair |
| Wikidata item | Q1108427 |

## Also known as

- IRAS: IRAS 11549+3237
- IRAS: IRAS F11549+3236
- LEDA: LEDA 37613
- MCG: MCG +06-26-060
- NGC: NGC 3991
- NGC: NGC 3991S
- PGC: PGC 37613
- UGC: UGC 6933

## 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 3991 \[catalogue entry\]. Data release DR1 (2026-08-21). https://spacecatalog.org/object/ngc-3991

```bibtex
@misc{spacecatalog_ngc-3991,
  author       = {{SpaceCatalog}},
  title        = {{NGC 3991}},
  howpublished = {SpaceCatalog, data release DR1 (2026-08-21)},
  year         = {2026},
  url          = {https://spacecatalog.org/object/ngc-3991},
  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-3991