Update nebula catalog: 21,033 nebulae

README.md

@@ -3,12 +3,7 @@ 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
+description: "Catalog of nebulae sourced from Wikidata, covering emission, reflection, dark, and planetary nebulae across the sky.  Nebulae are clouds of interstellar gas and dust -- the birthplaces of stars, the r"
 task_categories:
   - tabular-classification
 tags:
@@ -20,49 +15,51 @@ tags:
   - open-data
   - tabular-data
   - parquet
+size_categories:
+  - 10K<n<100K
 configs:
   - config_name: default
-    default: true
     data_files:
       - split: train
         path: data/nebulae.parquet
+    default: true
 ---
 
 # 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.
+<div align="center">
+  <img src="banner.jpg" alt="The Crab Nebula observed by the Hubble Space Telescope" width="400">
+  <p><em>Credit: NASA/ESA/Hubble</em></p>
+</div>
+
+
+*Part of a [dataset collection](https://huggingface.co/collections/juliensimon/astronomy-datasets-69c24caf2f17e36128946743) on Hugging Face.*
 
 ## 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.
+Catalog of nebulae sourced from Wikidata, covering emission, reflection, dark, and planetary nebulae across the sky.
+
+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), and representative catalog identifiers. This enables sky-survey cross-matching, population studies by type or constellation, and spatial distribution analysis.
+
+Sourced from Wikidata SPARQL using P31 (instance of) for emission (Q207326), reflection (Q167278), dark (Q46587), and planetary (Q204194) nebulae.
 
-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.
+This dataset is suitable for **tabular classification** tasks.
 
 ## 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) |
+| Column | Type | Description | Sample | Null % |
+|--------|------|-------------|--------|--------|
+| `wikidata_id` | string | Wikidata entity ID (e.g. 'Q12345'); stable URI for cross-referencing other catalogs and knowledge bases | Q85589522 | 0.0% |
+| `name` | string | Common or catalog name as recorded in Wikidata (e.g. 'Orion Nebula', 'NGC 1499', 'Barnard 68'); null for objects with no recorded label | 2dFS 1734 | 0.0% |
+| `nebula_type` | string | Physical nebula class: 'planetary nebula' (expanding shell from AGB star), 'emission nebula' (ionized HII region), 'reflection nebula' (dust scattering starlight), 'dark nebula' (opaque dust blocking background), 'supernova remnant' (ejecta from stellar explosion) | dark nebula | 0.0% |
+| `constellation` | string | IAU constellation in which the nebula is located (e.g. 'Orion', 'Cygnus'); null if not recorded in Wikidata | Tucana | 2.0% |
+| `ra_deg` | float64 | Right ascension in decimal degrees, ICRS J2000.0; range 0-360; null if coordinates not in Wikidata | 15.773833 | 0.8% |
+| `dec_deg` | float64 | Declination in decimal degrees, ICRS J2000.0; range -90 to +90; null if coordinates not in Wikidata | -72.167944 | 0.8% |
+| `catalog_id` | string | Cross-reference identifiers from NGC, IC, Messier, and other catalogs, semicolon-separated (e.g. 'NGC 1952; M 1'); null for objects catalogued only in Wikidata | 2dFS 1734; MCPS 1.051561-72.16803; OG... | 0.1% |
 
 ## Quick stats
 
@@ -82,6 +79,13 @@ reflection (Q167278), dark (Q46587), and planetary (Q204194) nebulae.
 ```python
 from datasets import load_dataset
 
+ds = load_dataset("juliensimon/nebula-catalog", split="train")
+df = ds.to_pandas()
+```
+
+```python
+from datasets import load_dataset
+
 ds = load_dataset("juliensimon/nebula-catalog", split="train")
 df = ds.to_pandas()
 
@@ -96,50 +100,45 @@ print(pn[["name", "constellation", "ra_deg", "dec_deg"]].head(10))
 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")
+# Distribution by type
+import matplotlib.pyplot as plt
+df["nebula_type"].value_counts().plot.barh()
+plt.xlabel("Count")
+plt.title("Nebulae by Type")
+plt.tight_layout()
+plt.show()
 ```
 
 ## 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.
+https://www.wikidata.org/
 
 ## 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
+- [juliensimon/planetary-nebulae](https://huggingface.co/datasets/juliensimon/planetary-nebulae)
+
+- [juliensimon/ngc-ic-catalog](https://huggingface.co/datasets/juliensimon/ngc-ic-catalog)
 
-## Pipeline
+- [juliensimon/messier-catalog](https://huggingface.co/datasets/juliensimon/messier-catalog)
 
-Source code: [juliensimon/space-datasets](https://github.com/juliensimon/space-datasets)
+> If you find this dataset useful, please consider [giving it a like](https://huggingface.co/datasets/juliensimon/nebula-catalog) on Hugging Face. It helps others discover it.
 
-## Support
+## About the author
 
-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.
+Created by [Julien Simon](https://julien.org) — AI Operating Partner at Fortino Capital. Part of the [Space Datasets](https://julien.org/datasets) collection.
 
 ## Citation
 
 ```bibtex
 @dataset{nebula_catalog,
-  author = {Simon, Julien},
   title = {Nebula Catalog},
+  author = {juliensimon},
   year = {2026},
-  publisher = {Hugging Face},
   url = {https://huggingface.co/datasets/juliensimon/nebula-catalog},
-  note = {Sourced from Wikidata (CC0)}
+  publisher = {Hugging Face}
 }
 ```
 
 ## License
 
-[CC0-1.0](https://creativecommons.org/publicdomain/zero/1.0/) (Wikidata content is public domain)
+[CC0-1.0](https://creativecommons.org/licenses/by/4.0/)

data/nebulae.parquet

@@ -1,3 +1,3 @@
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