Update AAVSO VSX: 10,300,820 variable stars

README.md

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+---
+license: cc-by-4.0
+pretty_name: "AAVSO Variable Star Index (VSX)"
+language:
+  - en
+description: "AAVSO Variable Star Index (VSX) catalog with 10,300,820 variable stars including types, periods, magnitudes, and spectral classifications."
+task_categories:
+  - tabular-classification
+  - tabular-regression
+tags:
+  - space
+  - variable-stars
+  - aavso
+  - vsx
+  - astronomy
+  - open-data
+  - tabular-data
+size_categories:
+  - 1M<n<10M
+configs:
+  - config_name: default
+    data_files:
+      - split: train
+        path: data/aavso_vsx_variable_stars.parquet
+    default: true
+---
+
+# AAVSO Variable Star Index (VSX)
+
+*Part of the [Astronomy Datasets](https://huggingface.co/collections/juliensimon/astronomy-datasets-69c24caf2f17e36128946743) collection on Hugging Face.*
+
+The AAVSO Variable Star Index (VSX) is the most comprehensive catalog of variable stars,
+containing **10,300,820** entries with variable star classifications, photometric properties,
+periods, and spectral types. VSX is maintained by the American Association of Variable Star
+Observers and is the standard reference for variable star research.
+
+## Dataset description
+
+VSX aggregates variable star data from hundreds of surveys and catalogs worldwide including
+OGLE, ASAS-SN, ZTF, Gaia, and AAVSO observer submissions. Each entry represents a unique
+variable or suspected variable star with its variability type, brightness range, period (if
+known), epoch, and spectral classification.
+
+Of the 10,300,820 entries, **4,830,314** have a measured period and
+**10,292,210** have a variability classification.
+
+## Key columns
+
+| Column | Type | Description |
+|--------|------|-------------|
+| `aavso_uid` | Int64 | AAVSO unique object identifier |
+| `name` | string | Primary designation |
+| `ra_deg` | float64 | Right ascension J2000 (degrees) |
+| `dec_deg` | float64 | Declination J2000 (degrees) |
+| `variable_type` | string | Variability type (e.g., EW, SR, RRAB, DSCT) |
+| `var_flag` | Int64 | Variability flag (0=confirmed, 1=suspected) |
+| `mag_max` | float64 | Maximum brightness (magnitude at max light) |
+| `mag_max_passband` | string | Passband for max magnitude |
+| `mag_min` | float64 | Minimum brightness / amplitude |
+| `mag_min_passband` | string | Passband for min magnitude |
+| `min_is_amplitude` | string | Y if mag_min is amplitude, not absolute magnitude |
+| `period_days` | float64 | Period in days |
+| `epoch_jd` | float64 | Epoch of maximum/minimum (Julian Date) |
+| `spectral_type` | string | Spectral classification |
+| `mag_range` | float64 | Derived magnitude range (mag_min - mag_max) |
+
+Full schema includes 22 columns with uncertainty flags and limit flags.
+
+## Top variability types
+
+| Type | Count |
+|------|-------|
+| `ROT` | 2,352,208 |
+| `E` | 1,987,833 |
+| `L` | 1,604,633 |
+| `RS` | 719,268 |
+| `DSCT|GDOR|SXPHE` | 717,928 |
+| `S` | 493,290 |
+| `EW` | 397,843 |
+| `SR` | 323,058 |
+| `VAR` | 310,300 |
+| `RRAB` | 189,791 |
+
+## Quick stats
+
+- **10,300,820** variable star entries
+- **4,830,314** with measured period (46.9%)
+- **10,292,210** with variability classification (99.9%)
+- RA range: 0.0001 to 360.0000 degrees
+- Dec range: -89.9288 to 89.9038 degrees
+
+## Usage
+
+```python
+from datasets import load_dataset
+
+ds = load_dataset("juliensimon/aavso-vsx-variable-stars", split="train")
+df = ds.to_pandas()
+
+# Eclipsing binaries with known periods
+eclipsing = df[df["variable_type"].str.startswith("E", na=False) & df["period_days"].notna()]
+print(f"Eclipsing binaries with periods: {len(eclipsing):,}")
+
+# Period-amplitude diagram for RR Lyrae
+rrab = df[df["variable_type"] == "RRAB"]
+import matplotlib.pyplot as plt
+plt.scatter(rrab["period_days"], rrab["mag_range"], s=0.5, alpha=0.3)
+plt.xlabel("Period (days)")
+plt.ylabel("Amplitude (mag)")
+plt.title("RR Lyrae (RRAB) Period-Amplitude Diagram")
+plt.show()
+
+# Sky distribution
+plt.hexbin(df["ra_deg"], df["dec_deg"], gridsize=200, mincnt=1)
+plt.colorbar(label="Star count")
+plt.xlabel("RA (deg)")
+plt.ylabel("Dec (deg)")
+plt.title("VSX Variable Stars Sky Density")
+plt.show()
+```
+
+## Data source
+
+Watson, C.L., Henden, A.A., & Price, A. (2006), *The International Variable Star Index (VSX).*
+Society for Astronomical Sciences 25th Annual Symposium on Telescope Science, p. 47.
+Maintained by AAVSO: [https://www.aavso.org/vsx/](https://www.aavso.org/vsx/)
+
+## Pipeline
+
+Source code: [juliensimon/space-datasets](https://github.com/juliensimon/space-datasets)
+
+## Citation
+
+```bibtex
+@dataset{aavso_vsx_variable_stars,
+  author = {Simon, Julien},
+  title = {AAVSO Variable Star Index (VSX)},
+  year = {2026},
+  publisher = {Hugging Face},
+  url = {https://huggingface.co/datasets/juliensimon/aavso-vsx-variable-stars},
+  note = {Based on AAVSO VSX (Watson et al. 2006)}
+}
+```
+
+## License
+
+[CC-BY-4.0](https://creativecommons.org/licenses/by/4.0/)

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