12.5" F6 自製牛頓望遠鏡 (01) ---- 粗磨中

[Wah!]

呢塊玻璃已在我家沉睡了差不多兩年,當時已被磨至3mm深.
近來見到陳輪輪同班學生哥磨24"大鏡磨得咁過癮,搞到個心都痕曬.
(第二個原因係體重暴漲,有需要消耗下能量 )

所以約埋豆貓每個星期都入農莊一齊發功磨鏡,希望好快可以磨好啦!
曾經問過黃sir,陳輪輪等人的意見,又睇過書(How to make Dobsonian Telescope)話F6鏡的彗差遠比短焦鏡的少,所以就跟住呢個方案去磨.

主鏡玻璃的厚度是1.625",而工具板則為0.75"厚.

今天是首次二人合力磨鏡,原來真係好省氣力架!但正因為太省氣力,連磨過龍都唔知道,磨至3.5mm,比原定計劃深左0.3mm, 而且邊緣仍然未磨過 !!!

由於之前用的30號砂已用光,只好用80號砂,以鏡下模上(1/3磨程,正心)的方法,希望可以磨至整個鏡面.經過兩個小時的工作,效果未如理想.所以下次會帶40號砂入農莊,希望這個過程可以加快,而且可以減少深度至3.175mm.

[扒飯撈麵]

wah~
although "light" soft drink carry less calories, i think drinking pure water is better for you.

[Passerby-B]

wah~
although "light" soft drink carry less calories, i think drinking pure water is better.

The sweaterners in soft drinks could be carcinogenic
Young people should avoid them

[Wah!]

我都唔喜歡飲softdrinks,我都係喜歡飲水的人呢!

咦?會唔會有d離左題呢:?

[Chanlunlun]

所以約埋豆貓每個星期都入農莊一齊發功磨鏡,希望好快可以磨好啦!

Dear Mr. Wah!,

There is one thing I forgot to tell - Pyrex is very hard glass. It is much harder than plate float glass, so prepare to spend twice the effort on rough grinding. Also pyrex polishes slowly, again prepare to spent twice as much effort for polishing the mirror, comparing with that of plate float glass.

Advancement in technology produces new brand of float glass so soft that it can be grinded and polished in an astounishing easy manner. They are also prefectly annealed. That's why we are able to make giant mirror with stunning thin thickness. Plate float glass is also my first choice of mirror making, since it is cheap and perfectly stress free.

Anyway Pyrex is a good stuff. It's good to have a taste of luxury in your telescope.

Wishing that you get everything running smooth in your ATMing.

Best retgards

Chan Yuk Lun

[Wah!]

銼邊時已完全感受到Pyrex的硬度喇!
上星期銼Pyrex的邊花去超過半小時,今天銼青玻璃只用了十多分鐘.

[豆豸苗]

其實呢.... 我地都冇咁多錢買塊係 Pyrex 番來0架....
只係本著唔好浪費左呢塊玻璃咁0者~~ ^^||||

反而我地最擔心係機械部份, 機械部份要諗好多野... (如果我地粗粗地整個殼, 睇落都唔會 luxury 得去邊 le~~ :p)
相對來講, 磨鏡部份我諗都只係人力同時間0既問題. 我估用埋 2000 號砂會拋光拋得快0的? (希望啦~~)

[layanata]

以下為豆貓和Wah!一起努力磨鏡的相片

[Subaru]

第一張相影到wah!師傅好科.

[layanata]

還有

[Wah!]

lalalala你想我delete你d相呀!
咁你都post出來!!!!

[豆豸苗]

wa?! ^^|||

[layanata]

十二吋主鏡...

[豆豸苗]

lalalala 用新機用得開心嘛~~~

[dtschan]

Where can we go to "電鍍" the mirror? How much? Very difficult to find from yellow page!