DIY 平價望遠鏡抱箍

[鄧登凳]

小弟有支C80, FL=400mm, f/5的普消鏡, 一直想用來做導星鏡, 本來有英田的抱箍(近500人仔一對 ), 但太重, 且想留給支80ED用。

今天沒有得上山, 去深水埗買了些東西, 實行DIY鏡箍。

用料:
1. 不銹鋼口喉箍(3.5吋)兩個, 底部是3/8螺絲孔的短桿, 包了PTFE膠套。$70.
2. 相機配件的 1/4變3/8螺絲套2個 $20
3. 1.5吋 1/4" 不銹鋼螺絲四口, 螺絲帽4個, 彈簧介子8個, 共$17
4. 可調左右雙相機座一個 $95

(總成本 $202 )

要2是因為要接入4的相機配件, 相機底的螺絲是1/4"的。
要3是因為原本的螺絲不夠長, 加了彈簧介子螺絲較不會鬆懈。
用4是因為要有兩個接點, 保持鏡不的方向(prevent flexture in autoguiding), 而可以前後移, 方便在赤道儀上的平衡。而除去底座, 那條有刻度的桿, 是可用Vixen style 鳩尾座來固定的。

[anthony168]

very good.
I still need one 導星鏡, is it expensive? or just use cheap telescope is okay? How big the D should be?
Many thanks!

[Eddy So]

不如考慮這個：
http://item.taobao.com/item.htm?id=1898862219
或以下這裡的其中一個：
http://s.taobao.com/search?q=%B1%A7%B9% ... =price-asc

[鄧登凳]

very good.
I still need one 導星鏡, is it expensive? or just use cheap telescope is okay? How big the D should be?
Many thanks!

80mm achromatic refractors cost a few hundred dollars.

The larger the aperture, the more easy the guide camera detects stars. Usually, 45mm is the lower end. Many people use 60~80mm. I have used a 66mm ED telescope but it is a bit too heavy.

If you need one, Wah!! is selling a 60mm version: http://www.hkastroforum.net/viewtopic.php?t=20013

[anthony168]

tks

[anyone]

Tang sir , 理論和實踐都掂，確係萬能博士！