humbleservant88
发表于 2005-6-15 14:22
denebman
发表于 2005-6-15 19:58
The oil spaced lens doesn't need extensive figuring of the internal optical surfaces, any minor error and roughness is tolerable since the oil compensates these errors, as a result, only the most front and rear air/glass interfaces need to be figured accurately, this brings down the production cost. However, the tradeoff is less freedom for lens optimization.
A good air-spaced objective lens must have all its optical surfaces well figured(e.g. a triplet has 6 nos), the pay back is more freedom for performance enhancement however at the expense of more polishing work and cost.
Mikhail
发表于 2005-6-16 18:01
呵呵，建议老大再开辟一个英语讨论专版。
humbleservant88
发表于 2005-6-17 01:09
denebman
发表于 2005-6-17 11:52
you are welcome, for more information, please visit
http://alice.as.arizona.edu/~rogerc/chapters/Chapter%204a.html (on doublet)
http://alice.as.arizona.edu/%7Erogerc/chapters/Chapter%204b.html (on triplet)
ufo
发表于 2005-6-17 12:00
呵呵，建议老大再开辟一个英语讨论专版。
学天文知识同时学英语，很不错嘛 ^^