# BL Herculis

> variable star in the constellation Hercules

**Wikidata**: [Q56298573](https://www.wikidata.org/wiki/Q56298573)  
**Wikipedia**: [English](https://en.wikipedia.org/wiki/BL_Herculis)  
**Source**: https://4ort.xyz/entity/bl-herculis


## References

1. General Catalogue of Variable Stars
2. SIMBAD
3. [SIMBAD](http://simbad.u-strasbg.fr/simbad/sim-basic?Ident=BL+Her&submit=SIMBAD+search)
4. The Henry Draper Extension Charts: A catalogue of accurate positions, proper motions, magnitudes and spectral types of 86933 stars
5. General Catalogue of Variable Stars, 3rd ed.
6. The Tycho-2 catalogue of the 2.5 million brightest stars
7. Catalogue of Stellar Photometry in Johnson's 11-color system
8. VizieR Online Data Catalog: 2MASS All-Sky Catalog of Point Sources (Cutri+ 2003)
9. Gaia Early Data Release 3
10. Gaia Data Release 2
11. Type II Cepheids: evidence for Na-O anticorrelation for BL Her type stars?