# William Henry Pickering

> American astronomer (1858–1938)

**Wikidata**: [Q310222](https://www.wikidata.org/wiki/Q310222)  
**Wikipedia**: [English](https://en.wikipedia.org/wiki/William_Henry_Pickering)  
**Source**: https://4ort.xyz/entity/william-henry-pickering

## Summary
William Henry Pickering was an American astronomer born on February 15, 1858, who made significant contributions to the field of astronomy, particularly through his work at the Harvard College Observatory. He is best known for his discoveries related to the Moon and his extensive cataloging of astronomical data.

## Biography
- **Born**: February 15, 1858
- **Nationality**: American
- **Education**: Harvard University (graduated in 1879)
- **Known for**: Lunar photography, cataloging astronomical data, and discovering the Moon's libration
- **Employer(s)**: Harvard College Observatory
- **Field(s)**: Astronomy

## Contributions
- **Lunar Photography and Libration Discovery**: Pickering conducted detailed photographic studies of the Moon, leading to the discovery of its libration, which explains the slight rocking motion of the Moon as seen from Earth.
- **Astronomical Cataloging**: He contributed to the cataloging of stars and other celestial objects, enhancing the field's foundational data.
- **Harvard College Observatory Work**: As a staff member, Pickering participated in large-scale astronomical projects, including the classification of stars and the study of variable stars.

## FAQs
**What were William Henry Pickering's major contributions to astronomy?**  
Pickering significantly advanced lunar studies through detailed photography and the discovery of the Moon's libration. He also contributed to extensive astronomical cataloging efforts at Harvard College Observatory.

**Where did Pickering conduct his notable work?**  
His primary work was undertaken at the Harvard College Observatory, where he collaborated on major astronomical projects and data collection initiatives.

**What specific lunar phenomenon did Pickering discover?**  
He identified the Moon's libration, a subtle oscillation that allows more than 50% of the lunar surface to be observed from Earth over time.

## Why They Matter
William Henry Pickering's meticulous lunar studies and cataloging work provided critical data for subsequent astronomical research. His discovery of the Moon's libration deepened understanding of lunar mechanics, influencing both scientific study and space exploration planning. Without his contributions, the foundational knowledge of lunar behavior and celestial mapping would be less comprehensive, impacting later advancements in astronomy and space science.

## Notable For
- **Lunar Libration Discovery**: First to document the Moon's libration, enhancing lunar observation and study.
- **Prolific Cataloger**: Contributed to extensive star and celestial object catalogs, supporting broader astronomical research.
- **Harvard Observatory Affiliation**: Key team member at a leading astronomical institution, collaborating on landmark projects.

## Body

### Early Life and Education
William Henry Pickering was born on February 15, 1858, in the United States. He pursued higher education at Harvard University, graduating in 1879. This academic foundation laid the groundwork for his future career in astronomy.

### Career and Contributions
Pickering's professional career was closely tied to the **Harvard College Observatory**, where he played a pivotal role in several large-scale astronomical endeavors. His work encompassed:

- **Lunar Studies**: Pickering's detailed photographic analyses of the Moon led to the identification of its **libration**—a phenomenon where the Moon appears to rock slightly, allowing observation of more than half its surface over time. This discovery was pivotal for understanding lunar mechanics and supported later lunar exploration efforts.
- **Astronomical Cataloging**: He contributed to the systematic cataloging of stars and celestial objects, a critical task for organizing astronomical data. This work aligned with broader efforts at Harvard to classify and document the night sky.
- **Collaborative Projects**: As part of the observatory team, Pickering participated in studies of variable stars and other celestial phenomena, contributing to the era's scientific discourse.

### Legacy and Influence
Pickering's contributions to lunar science and astronomical data collection left a lasting impact on the field. His work on libration informed both theoretical models of lunar motion and practical aspects of space mission planning. The catalogs he helped develop remained essential references for astronomers, underscoring the importance of meticulous data gathering in advancing scientific knowledge. While not as widely recognized as some contemporaries, Pickering's role in these foundational projects ensured his legacy as a diligent contributor to early 20th-century astronomy.

### Affiliations and Recognition
- **Employment**: Primarily associated with **Harvard College Observatory**, a leading institution in astronomical research during his tenure.
- **Awards and Honors**: Though specific accolades are not detailed in the source material, his discoveries and contributions were recognized within the scientific community of his time, reflected in his ongoing affiliation with Harvard and participation in key projects.

### Historical Context
Pickering's career spanned a period of significant growth in astronomy, marked by technological advancements in photography and observational techniques. His work exemplified the era's emphasis on empirical data collection and the systematic study of celestial bodies, setting the stage for future breakthroughs in astrophysics and space exploration.

## References

1. Integrated Authority File
2. [Source](https://achievement.org/our-history/golden-plate-awards/all-honorees/)
3. International Standard Name Identifier
4. Virtual International Authority File
5. CiNii Research
6. SNAC
7. Croatian Encyclopedia
8. [Encyclopædia Britannica](http://www.britannica.com/EBchecked/topic/459416/William-Henry-Pickering)
9. [Source](https://articles.adsabs.harvard.edu/pdf/1938PASP...50..122C)
10. Freebase Data Dumps. 2013
11. CONOR.SI
12. Library of Congress Control Number