Bernhard Walther was a Nuremberg merchant who formed an early collaboration with Regiomontanus in astronomical observations. It was however only after Regiomontanus did not return from his fateful trip to Rome in 1476 that Walther started lifelong observations of the night sky.
Walther is now regarded as the first “modern day” observer. He made systematic observations that where later used to form the backbone of a catalogue published by Schoener in 1544. These observations where republished by Snell in 1618 and in that form have remained the earliest observations used in this era.
Being a merchant Walther was able to afford the cost of a variety of instruments with which he observed the movements, of the Sun, Moon, and planets.
He used a modification of Ptolemy’s parallactic rulers to measure hundreds of solar zenith distances and so provide accurate observations of the Suns movement. A rectangulum instrument, like a cross staff was used for measuring hundreds of angular distances between planets and fixed stars until 1488. In 1488 he acquired an armillary with which he was able to make hundreds of direct observations of the longitude and latitude of planets. He died aged 74 on the Nineteenth of June 1504 (one of his busiest years of observations).
Copernicus who relied heavily on the observations of others, including Walther to produce “Revolution of the Heavenly Spheres” started his own observations around 1504.
I have not been able to find much personal information on Walther, he is now a largely forgotten figure. However he has been well enough regarded to have a 100 km lunar crater named after him
By Colin Maskill
References
N.M. Swerdlow "Astronomy in the Renaissance in Astronomy before Telescope,"
Cambridge History of Astronomy
