juliensimon/nebula-catalog

---
license: cc0-1.0
pretty_name: "Nebula Catalog"
language:
- en
description: >-
Catalog of nebulae sourced from Wikidata, covering emission, reflection,
dark, and planetary nebulae. 21,033 entries with coordinates, distances,
angular sizes, and constellation assignments.
size_categories:
- 10K<n<100K
task_categories:
- tabular-classification
tags:
- space
- astronomy
- nebulae
- deep-sky
- wikidata
- open-data
- tabular-data
- parquet
configs:
- config_name: default
default: true
data_files:
- split: train
path: data/nebulae.parquet
---

# Nebula Catalog

*Part of the [Astronomy Datasets](https://huggingface.co/collections/juliensimon/astronomy-datasets-69c24caf2f17e36128946743) collection on Hugging Face.*

A comprehensive catalog of **21,033** nebulae sourced from [Wikidata](https://www.wikidata.org/),
covering emission, reflection, dark, and planetary nebulae across the sky.

## Dataset description

Nebulae are clouds of interstellar gas and dust — the birthplaces of stars,
the remnants of dying ones, and some of the most visually spectacular objects
in the universe. This dataset aggregates structured data from Wikidata's
knowledge base, drawing on decades of cataloguing from Messier, NGC, IC, and
other surveys.

Each entry includes the nebula's name, type, host constellation, equatorial
coordinates (right ascension and declination), distance from Earth, angular
size on the sky, and a representative catalog identifier. This enables
sky-survey cross-matching, population studies by type or constellation, and
distance/size distribution analysis.

Sourced from Wikidata SPARQL using P31 (instance of) for emission (Q207326),
reflection (Q167278), dark (Q46587), and planetary (Q204194) nebulae.

## Schema

| Column | Type | Description |
|--------|------|-------------|
| `wikidata_id` | string | Wikidata entity ID (e.g. Q12345) |
| `name` | string | Common or catalog name |
| `nebula_type` | string | Nebula type (emission, reflection, dark, planetary) |
| `constellation` | string | Host constellation |
| `ra_deg` | float | Right ascension (degrees) |
| `dec_deg` | float | Declination (degrees) |
| `catalog_id` | string | Catalog identifiers (NGC, IC, Messier, etc.; semicolon-separated) |

## Quick stats

- **21,033** nebulae total
- **20,864** with equatorial coordinates
- **21,018** with catalog identifiers
- Top constellations: Aquila (2,352), Scutum (1,750), Scorpius (1,656), Sagittarius (1,648), Cygnus (1,409)

### Breakdown by type

- **dark nebula**: 21,031
- **emission nebula**: 1
- **reflection nebula**: 1

## Usage

```python
from datasets import load_dataset

ds = load_dataset("juliensimon/nebula-catalog", split="train")
df = ds.to_pandas()

# Count by nebula type
print(df["nebula_type"].value_counts())

# Planetary nebulae with coordinates
pn = df[(df["nebula_type"] == "planetary nebula") & df["ra_deg"].notna()]
print(pn[["name", "constellation", "ra_deg", "dec_deg"]].head(10))

# Nebulae in Orion
orion = df[df["constellation"] == "Orion"]
print(f"{len(orion):,} nebulae in Orion")

# Dark nebulae
dark = df[df["nebula_type"] == "dark nebula"]
print(f"{len(dark):,} dark nebulae")
```

## Data source

[Wikidata](https://www.wikidata.org/) SPARQL endpoint. Nebulae identified via
property P31 (instance of) for four nebula-type entities. Data is
community-curated and reflects contributions from astronomical cataloguing
projects worldwide.

## Update schedule

Quarterly (January, April, July, October). Re-run manually at any time to
pick up newly catalogued objects.

## Related datasets

- [planetary-nebulae](https://huggingface.co/datasets/juliensimon/planetary-nebulae) -- dedicated planetary nebula catalog
- [ngc-ic-catalog](https://huggingface.co/datasets/juliensimon/ngc-ic-catalog) -- NGC/IC catalog of deep-sky objects
- [messier-catalog](https://huggingface.co/datasets/juliensimon/messier-catalog) -- Messier catalog

## Pipeline

Source code: [juliensimon/space-datasets](https://github.com/juliensimon/space-datasets)

## Support

If you find this dataset useful, please give it a ❤️ on the [dataset page](https://huggingface.co/datasets/juliensimon/nebula-catalog) and share feedback in the Community tab! Also consider giving a ⭐️ to the [space-datasets](https://github.com/juliensimon/space-datasets) repo.

## Citation

```bibtex
@dataset{nebula_catalog,
author = {Simon, Julien},
title = {Nebula Catalog},
year = {2026},
publisher = {Hugging Face},
url = {https://huggingface.co/datasets/juliensimon/nebula-catalog},
note = {Sourced from Wikidata (CC0)}
}
```

## License

[CC0-1.0](https://creativecommons.org/publicdomain/zero/1.0/) (Wikidata content is public domain)