Polishing of 24 inch mirror started

[Chanlunlun]

Dear ATMs,

Today we finally took the decisive step. We had employed the old 14 inch tool to pour a sub-diameter lap. This was a simple task, comparing with the making of a 24 inch full size one.

Commencement of polishing followed immediately after the lap had cooled down ( actually we proceeded with polishing even when the lap was still a little warm ). To our surprise the polishing action seemed to be fast, despite the fact that the lap has a diameter of only 14 inches.

Mirror must face upward in this situation and thus we were forced to use circular stroke to avoid astigmatism. Mr. Sodium had spent some times in polishing this giant mirror.

Hopefully polishing will be finished within ten working hours. Judging from the on going progress, we are quite confident that this could be accomplished.

Best regards

Chan Yuk Lun
4-3-2004

[豆豸苗]

阿 sodium 好努力咁喎~ ^^

點解唔係好覺有拋光粉咁0既? 咁大塊面, 0的拋光粉會唔會拋得一陣就好快乾左呢?

[Chanlunlun]

阿 sodium 好努力咁喎~ ^^

點解唔係好覺有拋光粉咁0既? 咁大塊面, 0的拋光粉會唔會拋得一陣就好快乾左呢?

Dear Miss BeanKitty,

There were polishing powder on mirror surface but you don't see it in the photo. The evaporation rate of polishing liquid was not that high, it was more or less the same as polishing small mirror.

Since polishing powder is a very expensive item and the mirror is very large, we use as little powder as possible to keep the cost low.

In building large telescope financial control is essential. We try every step to lower the building cost of the 24 inch.

Best regards

Chan Yuk Lun
5-3-2004