juliensimon/messier-catalog

---
license: cc-by-4.0
pretty_name: "Messier Catalog"
language:
- en
description: >-
The complete Messier catalog of 110 deep-sky objects — galaxies, nebulae, and
star clusters visible from the Northern Hemisphere. From SIMBAD.
size_categories:
- n<1K
task_categories:
- tabular-classification
tags:
- open-data
- astronomy
- messier
- deep-sky
- galaxy
- nebula
- star-cluster
- simbad
configs:
- config_name: default
data_files:
- split: train
path: data/messier.parquet
---

# Messier Catalog


The complete **Messier catalog** — 93 deep-sky objects catalogued by Charles Messier
in the 18th century. Includes 25 galaxies, 44 star clusters,
and 7 nebulae/remnants.

## Schema

| Column | Type | Description |
|--------|------|-------------|
| `messier_id` | string | Messier designation (M 1, M 2, ...) |
| `messier_number` | int | Messier number (1-110) |
| `name` | string | Primary SIMBAD name (e.g. "NGC 224", "Crab Nebula") |
| `ra_deg` | float | Right ascension (degrees) |
| `dec_deg` | float | Declination (degrees) |
| `object_type` | string | SIMBAD object type code |
| `object_category` | string | Human-readable category (Galaxy, Globular Cluster, etc.) |
| `major_axis_arcmin` | float | Major axis angular size (arcmin) |
| `minor_axis_arcmin` | float | Minor axis angular size (arcmin) |

## Quick stats

- **93** Messier objects
- **25** galaxies, **44** star clusters, **7** nebulae/remnants

## Usage

```python
from datasets import load_dataset

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

# Galaxies only
galaxies = df[df["object_category"].str.contains("Galaxy", na=False)]

# Objects by category
df["object_category"].value_counts()
```

## Update frequency

Updated **quarterly** via GitHub Actions.

## Data source

[SIMBAD Astronomical Database](https://simbad.u-strasbg.fr/) (CDS, Strasbourg).

## Related datasets

- [ngc-ic-catalog](https://huggingface.co/datasets/juliensimon/ngc-ic-catalog) — 14K deep-sky objects (NGC + IC)
- [quasar-catalog](https://huggingface.co/datasets/juliensimon/quasar-catalog) — 50K quasars and AGN
- [black-hole-catalog](https://huggingface.co/datasets/juliensimon/black-hole-catalog) — Known black hole systems

## Pipeline

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

## Citation

```bibtex
@dataset{messier_catalog,
author = {Simon, Julien},
title = {Messier Catalog},
year = {2026},
publisher = {Hugging Face},
url = {https://huggingface.co/datasets/juliensimon/messier-catalog},
note = {Based on SIMBAD astronomical database (CDS Strasbourg)}
}
```