---
title: "NGC 1820"
url: "https://spacecatalog.org/object/ngc-1820"
release: "DR1"
licence: "CC-BY-SA-4.0"
citation: "SpaceCatalog. NGC 1820 [catalogue entry]. Data release DR1 (2026-08-21). https://spacecatalog.org/object/ngc-1820"
---

# NGC 1820

NGC 1820 is an open [cluster](https://spacecatalog.org/clusters) in the constellation [Dorado](https://spacecatalog.org/constellation/dorado), shining at apparent magnitude 11.50 (V). It was discovered in 1837.

## At a glance

- **WHAT IT IS:** Open cluster
- **HOW BIG ON THE SKY:** 7.0′ — About 0.2 of the full Moon's width.
- **HOW BRIGHT (V):** 11.50 — A small telescope reaches it.
- **WHERE TO LOOK:** [Dorado](https://spacecatalog.org/constellation/dorado) — The patch of sky it sits in, as seen from Earth.

## Properties

| Quantity | Value |
| --- | --- |
| CLASS | Open cluster |
| APPARENT MAGNITUDE (V) | 11.50 |
| CONSTELLATION | Dorado |
| RIGHT ASCENSION (J2000) | 05h 04m 01.7s |
| DECLINATION (J2000) | −67° 15′ 57.4″ |
| DISCOVERED | 1837 |

## Catalogue data

### 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 (V) | 11.50 |

### 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 | 7′ |
| Minor axis | 5.4′ |
| Position angle | 20° |

### WHEN IT WAS FOUND

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

| Field | Value |
| --- | --- |
| Discovered by | John Frederick William Herschel |

### OTHER NAMES AND NUMBERS

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

| Field | Value |
| --- | --- |
| OpenNGC type code | OCl |
| Wikidata item | Q958550 |
| Wikipedia article | NGC 1820 |

## Also known as

- NGC: NGC 1820

## 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 1820 \[catalogue entry\]. Data release DR1 (2026-08-21). https://spacecatalog.org/object/ngc-1820

```bibtex
@misc{spacecatalog_ngc-1820,
  author       = {{SpaceCatalog}},
  title        = {{NGC 1820}},
  howpublished = {SpaceCatalog, data release DR1 (2026-08-21)},
  year         = {2026},
  url          = {https://spacecatalog.org/object/ngc-1820},
  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-1820