Conservation of scientific instruments in Brazil. Case study: defining the intervention criteria for the Bamberg elbow transit telescope of MAST

ABSTRACT The architectural complex of Observatório Nacional was completed in 1927, including the astronomical observation pavilions, of which one pavilion houses the Bamberg 10783 elbow telescope. All building architecture, collections and archiving funds were subject to registration by the Instituto do Patrimônio Histórico e Artístico Nacional (in 1986) and by the Instituto Estadual do Patrimônio Cultural (in 1987). The diagnosis and definition of the interventions in this Bamberg telescope of Museu de Astronomia e Ciências Afins (MAST) integrate this article. Due to cross-sectional nature of the conservator’s research going beyond materiality, we get information before any intervention in order to identify which values would be affected by possible treatments on damages and replacement parts. Utilizing a classification in 4 degrees of deterioration, taking as a tacit parameter the manuscript scratched in the varnish of the inversion elevator column, the diagnosis of the telescope revealed a significant percentage of unprotected metal surfaces, some fairly advanced localized corrosion, and a considerable percentage of uniform corrosion thin layer. The most symbolic damages on this elbow transit telescope only required minimal intervention and discussion on what would be the best course of action given the adverse conditions of its preservation in situ.

摘要
国家天文台（Observatório Nacional）建筑群于1927年竣工，包含多座天文观测台亭，其中一座台亭内安置有班贝格10783型肘式望远镜（Bamberg 10783 elbow telescope）。所有建筑本体、馆藏藏品与档案资料均先后于1986年由国家历史与艺术遗产研究所（Instituto do Patrimônio Histórico e Artístico Nacional）、1987年由州文化遗产研究所（Instituto Estadual do Patrimônio Cultural）完成登记备案。
本文围绕天文与相关科学博物馆（Museu de Astronomia e Ciências Afins, MAST）所藏的该台班贝格望远镜的保护干预方案展开诊断与界定。鉴于本保护研究兼具多维度属性且超越了物质本体范畴，本文在开展任何保护干预前先行收集相关信息，以明确在对损坏部件与更换构件采取处理措施时，会对哪些文物价值造成影响。本次诊断以4级劣化分级标准为框架，并以升降反转立柱漆面的手写字痕作为默认参照参数，结果显示该望远镜存在大量裸露未保护的金属表面、多处较为严重的局部腐蚀，以及大面积均匀薄层腐蚀。这台肘式中天望远镜最具标志性的损坏仅需最小限度的干预措施，且需结合其原位保存的不利条件，探讨最优的保护行动方案。