天顶的

As one of the most often used mountings, the altazimuth mounting satellite tracker has a blind area near the zenith because of the very high azimuth angular velocity, as a result, discontinuous observing data are caused. As for those fast flying satellites, this kind of blind area is very significant because it causes difficulties in precisely determining the satellites' orbits.

作为最常用的一种机架，采用地平式机架的人卫跟踪仪在观测天顶附近区域的目标时，由于方位转速过大而不能连续观测，存在一个固有的天顶盲区，特别是对飞行速度较快的近地卫星，这个盲区的影响是相当大的。

You'll also need a diagonal and if this is your first apochromatic refractor, I'll recommend a 3-6 nagler zoom.

如果这是你的第一架复消色差折射望远镜，那么你还需要一个天顶镜。我推荐用3－6毫米耐格勒变焦的天顶镜。

The basic principle is based on spherical astronomy and elementary geometry of the trajectory mapping method based on the observation of a celestial body zenith distance, then the ship is located in order to sing the next point as the center of this satellite zenith distance of the ship's position as the radius of the circle, observing the same two objects, or objects at different times of the two observations, we can get two ship's position round, then the ship must have been a point of intersection of two ship's position on the circle.

其基本原理是建立在球面天文学和初等几何中的轨迹作图法基础上的，观测一个天体的天顶距，则航船就位于以星下点为圆心，此星天顶距为半径的船位圆上，观测两个天体或者不同时间同一天体的两个观测值，就可以得到两个船位圆，则航船一定在两个船位圆的一个交点上。

In order to improve the monitoring precision and resolution of tropospheric zenith delay, the hybrid approach, using a batch least squares estimator but parameterizing the zenith delay by a linear spline with knots at 30-minute intervals and treating the knots as a Gauss-Markov process, is employed to deal with the tropospheric zenith delay.

为了提高对流层天顶延迟的监测精度和分辨率，我们采用了分段的参数估计和随机过程相结合的估算方法来处理对流层延迟，由此获得了分辨率分别为2 h和30 min，精度好于1 cm的天顶延迟量。

The results indicate that the distribution of the solar zenith distance versus the occurring probability of earthquakes is quite consistent with the lunar case, and the case for small earthquakes is different from the larger earthquakes. The latter is mainly clustered at 0oand l80o of the zenith distance, and consistent with the distribution of the absolute value of the solar tide forces, while the former are clustered at 60o and l2Oo.

统计发现：地震的太阳天顶距地震频度和月球天顶距地震频度分布表现出一致的规律性，且较大地震和小地震的活动规律不同，较大地震丛集发生在太阳天顶距0°和180°附近，与地面引潮力的绝对值分布有较好的一致性；而小地震多丛集在太阳天顶距60°和120°附近。

Based on the ISC earthquake catalogue data, according to the orbit equations of two-body-problem and the perturbation theory of celestial mechanics, we could determine the projection pole of the sun, and thus calculate the zenith distance from the sun to the epicenter. After calculating all the earthquakes on their zenith distances, we could get the distribution of the solar zenith distance versus the occurring probability of earthquakes.

基于ISC地震记录，利用天体动力学中二体问题的轨道方程和摄动理论，确定发震时刻太阳在地面的投影点位置，并进一步计算出太阳相对震中的地心天顶距，将地震按天顶距的大小进行统计，得到地震的太阳天顶距地震频度分布。

The corona type aurora mainly occurs at polarward and overhead of Zhongshan Station during postnoon and around midnight. The band type aurora mainly appears during postnoon, while during evening and around midnight only appears at equatorward.

冕状极光主要出现在子夜附近和午后的极向侧和天顶，在傍晚出现很少；带状极光主要出现在午后和赤道侧的傍晚与子夜；极光浪涌主要出现在子夜前后；向日极光弧则主要出现在子夜前后，子夜前比子夜后多，极向和天顶比赤道侧多。

The conclusion is that the extent of the zenith blind zone was restricted by three parameters: maximum azimuth angular velocity of tracking mount, flight level and airspeed of the target. In astronomical coordinates (reference mark is north latitude 43.9 ), analyzed is the effect of azimuth angular velocity, acceleration and altitude angular velocity, acceleration etc. Some formulae were given to compute all correlative quantities.

在观测坐标系中推导出确定天顶盲区理论范围公式和满足过天项跟踪条件的关系式；在天文坐标系中以长春卫星观测站(北纬43.9°)作为计算基准，分别讨论了方位、俯仰方向的角速度、角加速度等对天顶盲区的影响，在理论分析上为解决过天顶跟踪问题打下了基础。

Modern and practical astronomy was developed in the 18th century, and successively from the theoretical and practical solution to the Sino-satellite instrument measuring time, too Seoul Scott multi-satellite measurements such as latitude, as well as simultaneous determination of longitude and latitude Supreme Court means the emergence of theodolite, contour instrument, the satellite instrument, zenith instrument, photographic zenith tube, sextant and other useful astronomical instruments, the most commonly used is the optical theodolite .20 century, all-round practical field of astronomy 60 years after the emergence of new technologies, such as satellite Dhoop Le observation and satellite laser ranging, not only the accuracy of more than optical observations, but also greatly improved operating speed, and can provide direct point of geocentric coordinates of the ground.

现代实用天文学是18世纪发展起来的，先后从理论和实践上解决了中星仪测时、太尔各特测纬以及多星等高法同时测定经度和纬度的方法，出现了经纬仪、等高仪、中星仪、天顶仪、照相天顶筒、六分仪等实用天文学仪器，最常用的是光学全能经纬仪。20世纪60年代以后实用天文学领域出现了崭新的技术，如人造卫星多普勒观测和人卫激光测距，不但精度超过光学观测，而且作业速度大大提高，并能直接提供地面点的地心坐标。

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。

I didn't watch TV last night, because it .

昨晚我没有看电视，因为电视机坏了。

Since this year, in a lot of villages of Beijing, TV of elevator liquid crystal was removed.

今年以来，在北京的很多小区里，电梯液晶电视被撤了下来。