主焦点

He used an SBIG STL-11000M CCD camera at the f/3 prime focus of a 16-inch Cassegrain reflector for a total exposure time of 40 minutes.

他在一台16吋卡塞反射镜f/3焦比的主焦点上装置了一个***CCD，用于总计40分钟的曝光。

Focal length: The distance between the centre of a lens and its principal focus.

焦距：镜头中心与其主焦点的距离。

A C frame a larger diameter reflecting telescope, through the transformation with different sub-mirror, access to the main focus of the system, Cassegrain system and the fold-axis system.

一C架较大口径的反射望远镜，通过变换不同的副镜，可获得主焦点系统、卡塞格林系统和折轴系统。

Reflector telescope relative a larger diameter can be done, the main focus of the relative telescope diameter is about 15-125, even greater, Wang DC, inter Newton Telescope, the tube is longer than the system is much shorter focal length, coupled with the main mirror is only one apparent need for processing, which greatly reduces cost and manufacturing difficulties, there is currently greater than 134 meters diameter optical telescopes are all reflecting telescope.

反射望远镜的相对口径可以做得较大，主焦点式反射望远镜的相对口径约为15—125，甚至更大，而且除牛顿望DC远镜外，镜筒的长度比系统的焦距要短得多，加上主镜只有一个表面需要加工，这就大大降低了造价和制造的困难，因此目前口径大于134米的光学望远镜全部是反射望远镜。

Situated anterior to the frontal bone.

又称前焦点。凸透镜前面的主焦点

I will endeavour to find you some assistance.

我尽力帮你找人帮忙。

At first I only know bruck is the idol of American younglings, afterwards I returned back to Taiwan ,even in Beijing last year ,I saw her poster everywhere, I was so surprised at her charm.

起初我只晓得布鲁克雷德丝是美国少男少女崇拜的偶像，后来回台湾，甚至去年在北京，居然也四处看见她的海报，才惊讶她的魅力之大。