Searching beyond the Solar System

Thomas Henry Espin spent his life discovering stars. In an age before giant telescopes, Espin found and recorded over 2500 double stars and 4000 red stars. Double stars are pairs of stars that seem close together. Red stars are dying stars in the last stages of the stellar lifespan. Astronomers today use star catalogues to understand the life cycle of different stars.

Espin (1858-1934) studied theology (the nature of religious belief) at Oxford University. His interest in astronomy led him to use the University’s telescope to explore the night sky. At the age of twenty, he became the youngest ever member of the Royal Astronomical Society.

Espin later became a priest in Tow Law, County Durham, where he served for over 40 years. Espin never lost his interest in astronomy. He created an observatory close to his home.

This micrometer was invented by Espin for studying double stars. A micrometer has an eyepiece with two fine wires forming a cross. Astronomers use this cross to measure the distance between pairs of stars.

A double star is like a celestial duo, closely huddled in the vast sky. They can be a dynamic ‘binary pair’, drawn together by gravity, or an ‘optical duo’ where the stars look close due to the way they are seen in the sky. Reverend Espin found more than 2500 of these stellar partnerships in his lifetime.

A nova is the sudden appearance of a bright star-like object in the sky. These dazzling explosions can happen when stars pass too close to each other. Nova Persei was discovered in 1901. This book contains photographs of spectra. Spectra is light split into a rainbow. The photographs are by Frank McClean. McClean studied at Trinity College, Cambridge at the same time as Alexander Herschel.