Update GCVS variable stars: 60,894 stars

README.md

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+---
+license: cc-by-4.0
+pretty_name: "General Catalogue of Variable Stars (GCVS)"
+language:
+  - en
+description: "The canonical catalog of variable stars maintained since 1948 by the Sternberg Astronomical Institute, Moscow. Sourced via VizieR CDS Strasbourg."
+task_categories:
+  - tabular-classification
+tags:
+  - space
+  - variable-star
+  - astronomy
+  - gcvs
+  - stellar
+  - open-data
+size_categories:
+  - 10K<n<100K
+---
+
+# General Catalogue of Variable Stars (GCVS)
+
+![Update GCVS](https://github.com/juliensimon/space-datasets/actions/workflows/update-gcvs.yml/badge.svg)
+![Updated](https://img.shields.io/badge/dynamic/json?url=https://raw.githubusercontent.com/juliensimon/space-datasets/main/status.json&query=$.gcvs&label=updated&color=brightgreen)
+
+The General Catalogue of Variable Stars (GCVS) is **the** canonical reference catalog of variable
+stars, maintained since 1948 by the Sternberg Astronomical Institute at Moscow State University.
+Currently **60,894** variable stars with 544 variability types.
+
+## Dataset description
+
+Variable stars are stars whose brightness changes over time, either due to intrinsic physical
+processes (pulsation, eruption, rotation) or extrinsic geometry (eclipsing binaries). The GCVS
+is the internationally recognized authority for variable star designations and classifications.
+It has been compiled and updated for over 75 years, serving as the foundation for stellar
+variability research.
+
+Each entry includes the GCVS designation, coordinates, variability type, magnitude range,
+period, epoch of maximum, and spectral type where known.
+
+## Schema
+
+| Column | Type | Description |
+|--------|------|-------------|
+| `gcvs_name` | string | GCVS designation (e.g. "R And", "delta Cep") |
+| `ra_deg` | float64 | Right ascension J2000 (degrees) |
+| `dec_deg` | float64 | Declination J2000 (degrees) |
+| `variable_type` | string | Variability type (e.g. M, SR, EA, DCEP, RR) |
+| `magnitude_max` | float64 | Maximum brightness (mag, lower = brighter) |
+| `magnitude_min_flag` | string | Flag on minimum magnitude (e.g. "(" for amplitude) |
+| `magnitude_min` | float64 | Minimum brightness (mag) |
+| `period_days` | float64 | Period in days |
+| `epoch_jd` | float64 | Epoch of maximum/minimum (Julian Date) |
+| `spectral_type` | string | Spectral type |
+
+## Quick stats
+
+- **60,894** variable stars
+- **544** variability types
+- **40,096** with known period
+- **15,116** with spectral type
+- Top types: M (7,920), RRAB (7,590), EA (4,113), EW (3,616), LB (2,800)
+
+## Usage
+
+```python
+from datasets import load_dataset
+
+ds = load_dataset("juliensimon/gcvs-variable-stars", split="train")
+df = ds.to_pandas()
+
+# Cepheid variables (standard candles for distance measurement)
+cepheids = df[df["variable_type"].str.startswith("DCEP", na=False)]
+print(f"{len(cepheids):,} classical Cepheids")
+
+# Eclipsing binaries
+eclipsing = df[df["variable_type"].str.startswith("E", na=False)]
+print(f"{len(eclipsing):,} eclipsing binaries")
+
+# Period-luminosity distribution
+import matplotlib.pyplot as plt
+valid = df.dropna(subset=["period_days", "magnitude_max"])
+valid = valid[valid["period_days"] > 0]
+plt.scatter(valid["period_days"], valid["magnitude_max"], s=0.5, alpha=0.3)
+plt.xscale("log")
+plt.gca().invert_yaxis()
+plt.xlabel("Period (days)")
+plt.ylabel("Magnitude (max brightness)")
+plt.title("GCVS Period vs Magnitude")
+```
+
+## Data source
+
+[General Catalogue of Variable Stars](https://www.sai.msu.su/gcvs/gcvs/)
+(Samus' N.N., Kazarovets E.V., Durlevich O.V., Kireeva N.N., Pastukhova E.N., 2017,
+Astronomy Reports, 61, 80), accessed via [VizieR](https://vizier.cds.unistra.fr/), CDS Strasbourg.
+
+## Update schedule
+
+Quarterly (1st of the month at 08:00 UTC) via [GitHub Actions](https://github.com/juliensimon/space-datasets).
+
+## Related datasets
+
+- [pulsar-catalog](https://huggingface.co/datasets/juliensimon/pulsar-catalog) -- ATNF Pulsar Catalogue
+- [messier-catalog](https://huggingface.co/datasets/juliensimon/messier-catalog) -- Messier deep-sky objects
+- [ngc-ic-catalog](https://huggingface.co/datasets/juliensimon/ngc-ic-catalog) -- NGC/IC deep-sky catalog
+
+## Pipeline
+
+Source code: [juliensimon/space-datasets](https://github.com/juliensimon/space-datasets)
+
+## Citation
+
+```bibtex
+@dataset{gcvs_variable_stars,
+  author = {Simon, Julien},
+  title = {General Catalogue of Variable Stars (GCVS)},
+  year = {2026},
+  publisher = {Hugging Face},
+  url = {https://huggingface.co/datasets/juliensimon/gcvs-variable-stars},
+  note = {Based on GCVS (Samus' et al. 2017) via VizieR CDS Strasbourg}
+}
+```
+
+## License
+
+[CC-BY-4.0](https://creativecommons.org/licenses/by/4.0/)

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