# NGC 6638

> globular cluster

**Wikidata**: [Q1146828](https://www.wikidata.org/wiki/Q1146828)  
**Wikipedia**: [English](https://en.wikipedia.org/wiki/NGC_6638)  
**Source**: https://4ort.xyz/entity/ngc-6638


## References

1. SIMBAD
2. G2C2 – I. Homogeneous photometry for Galactic globular clusters in SDSS passbands
3. A catalog of parameters for globular clusters in the Milky Way
4. Testing three derivative methods of stellar population synthesis models
5. RR Lyrae-based calibration of the Globular Cluster Luminosity Function
6. Global survey of star clusters in the Milky Way