Reflecting telescope No. 22 by Jan van der Bildt junior

This lacquered brass reflecting telescope is signed ‘J. van der Bildt Jnr Franeker no.22’. It is made of lacquered brass and comes with its original dust cap. The objective tube (I 34, 0 7.5) contains a main mirror (7) and a secondary mirror (0 2.0). The eyepiece (I 6.5, 0 2.2) has a compound ocular and a dust coverage slide. Similar numbered telescopes of ‘Jan van der Bildt Junior’ are known ranging from no. 20 (Eisinga planetarium Franeker) to no. 63 (this telescope). One copy is known having an engraved date (‘ 1776’) instead of a number (SG Prof. Zeeman, Zierikzee). The brass folding tripod stand could be replacement because the mounting to the telescope and the decoration to the tripod is different to known examples.The maker, Jan van der Bildt the younger (1736- c. 1780), was a son of Jan van der Bildt the elder (1709-1791). Jan the elder was a famous Dutch telescope maker who was fortunate enough to work under the patronage of King Willem IV, who was a great fan of scientific developments, especially Newtonian physics. Willem IV supported the astronomical knowledge in Franeker with funds. The planetarium of Eise Eisinga (1744-1828), which was recently included in the Unesco World Heritage List, is the most famous artifact of this extraordinary period in Dutch history.Like his younger brother Lubbertus, Jan van der Bildt jr also made telescopes independently of his father from about 1768. Little is known of the life of these two sons. ln 1755 Jan van der Bildt Junior matriculated as a student at Franeker University. Following his marriage in 1762, he was convicted on several occasions for fighting and perjury. Jan Junior was operational until about 1780.Length objective tube:  34 cm Diameter objective tube: 7.5 cm