折射望远镜

This was the apochromatic refractor.

这就是APO折射式望远镜。

Towards the end of the 19th century, just as reflecting telescopes were coming into favor with professional astronomers, a new type of refracting telescope was built for the new field of astrophotography.

20世纪末，反射式望远镜正被专业的天文学家所青睐时，一种新型的折射式望远镜为天体摄影学制造出来。

Since their introduction in the early 17th century, refractors have suffered from one major defect: chromatic aberration.

色差是折射式望远镜自18世纪初推广以来所具有的主要缺陷。

A plane curve formed by the intersection of a right circular cone and a plane parallel to an element of the cone.

具有抛物面主镜和双曲面次镜的一种折射式望远镜；光线被集中到主镜中心的孔径。

The method does not depend on strict local parameters and precise instruments, while the observational principle is relatively simple. An experimental observation was carried out with a simple telescope with large field of view at Xinglong station of NAOC at the end of 2007. The atmospheric refraction from the zenith distance of 44.8 degree to 87.5 degree is gotten by the differential method, which proves the feasibility of the method tentatively.

该方法不依赖于严格的地方参数和复杂精密的观测仪器，并且观测原理相对简单。2007年底，利用一台简易的大视场望远镜在兴隆观测站进行了试验观测，根据较差方法实测得到真天顶距44.8°至87.5°的大气折射值，初步证明了大气折射较差测量方法的可行性。

By 1933 Zeiss had manufactured several proven refractors of the "E","A" and "AS" achromatic doublet designs, and apochromat triplets of the "U.V."

1933年，蔡司生产了&E&，&A&和&AS&等几款使用消色差镜头设计，并经过实际使用验证的折射望远镜，还有&U.V。&

Using the K20 eyepiece included as standard equipment, about 45x magnification, it's easy to see the Andromeda Galaxy and its smaller satellite galaxy M32. When compared to 60mm refractors, the Powerseeker 114 brings out much more detail in the Orion Nebula, reveals many more stars in Perseus' Double Cluster and even brings out a few individual stars in globular clusters like M13. Saturn looks quite small at 45x with the K20 eyepiece, but using my own 7.5mm eyepiece (120x) I can easily detect the shadow cast by the planet on the rings, and even glimpse the ring's Cassini Division. When the mirrors are properly lined up or "collimated," the images are reasonably sharp up to magnifications of 225x.

使用标准配件中的K20 目镜，可以得到45倍放大率，这时候很容易看到仙女座星系，还有较小的星系M32；和60毫米口径的折射望远镜相比，114 EQ可以看清更多猎户座星云的细节；瞄准英仙座双星团，看到的星体数量更多，显得更加壮丽；对于球状星团，比如M13，甚至可以显出其中少数独立的恒星；在K20 目镜下（放大45倍）的土星显得相当小，但换成我自己的7.5毫米焦距的目镜(得到120倍)，可以轻松的看到光环在土星上的投影，甚至可以瞥见土星光环内的卡西尼缝隙。

Starting with the zenith, a series of star fields at different altitude are observed by a telescope with larger field of view, the derivatives of various orders are calculated at different zenith distances, and finally the observational atmospheric refraction can be obtained by numerical integration.

利用一台较大视场的望远镜从天顶开始，在不同高度上对星空作一系列观测，计算不同天顶距处大气折射函数的各阶导数，最后经数值积分可给出大气折射实测值。

This TMB designed 111mm diameter f7 focal ratio triplet refractor is well constructed, offers a proprietary?

这款TMB的三角支架折射望远镜构造精良：111毫米的口径， F7的焦比。

Plates of globular cluster M3, taken with the 40cm refractor at Sheshan station of Shanghai Astronomical Observatory, are used by this work. The difference of epoch of these plates is up to 81years. The positions and absolute proper motions of 24 stars in ACT catalogue, which links with the Hipparcos Catalogue based on the International Celestial Reference System, are used as the reference frame. Using the central overlapping principle, the absolute proper motions of 534 stars in the region of about 100'×100' around the cluster are determined. After the membership determination of the stars which based on the data of proper motions, average absolute proper motion components for the cluster of -0.3±0.3 mas/yr in R.A.

本文使用上海天文台佘山40厘米折射望远镜拍摄的14张最长时间跨度为81年的球状星团M3底片的PDS扫描结果，使用与 Hipparcos星表相联系的基于国际大球惯性参考系的ACT星表中的 24颗恒星的位置和绝对自行为参考架，用中心重叠法进行天体测量归算，得到了这个星团中心附近100'×100'天区内534颗恒星的位置和绝对自行，并利用这些自行对成员概率进行了估算，得到这个星团的赤经方向绝对自行为- 0.3±0.3mas/yr，赤纬方向绝对自行为-3.1±0.3mas／yr。

In the negative and interrogative forms, of course, this is identical to the non-emphatic forms.

。但是，在否定句或疑问句里，这种带有"do"的方法表达的效果却没有什么强调的意思。

Go down on one's knees;kneel down

屈膝跪下。。。下跪祈祷