在那里，怎样观测!!!请看这里！！

在那里，怎样观测!!!请看这里！！
在星期六的晚上，8月17-18号，2002NY40在欧洲、美洲、非洲观察将达到10等或9等。虽然它能达到双筒望远镜所能观测的亮度，但是小口径望远镜能给你的的只是更多的满意的星体运动轨迹。观测者能够看到小行星在背景星空中随着时间而改变位置。当18日7：47（格林尼治时间）分小行星经过近地点时你能看到它向东运行8分钟。
为了帮助小行星的定位，“天空与望远镜”准备了4幅60平方度范围的星图，从天箭星座穿过狐狸座、天鹅座、天琴座、武仙座。每一个图表都是pdf格式的文件，你可以在任何计算机上使用Adobe公司Acrobat Readerhttp://www.adobe.com/products/acrobat/readstep2.html的3.0译本软件查看，还可以打印出来。
图表一 大体上是在欧洲、非洲的观测者使用。 在17日的20：00到18日的01：30。http://skyandtelescope.com/graphics/ChartA.pdf
图表二 包含的星空与轨迹适合北美洲的观测者。从1：30到4：30http://skyandtelescope.com/graphics/ChartB.pdf
图表三 显示了小行星的轨迹。适合在4：10到6：10在美国波士顿和洛山矶观测。
图表四 适合在北美的观测者 结束在7：40

因为视差的影响，小行星的精确轨迹按照你的地理位置。留下几个常见的几个大城市的上空星体运行的图纸，你可以按照你自己的地理位置估计小行星在空中运行的位置。
（例如在美国丹佛上空的轨迹应该在波士顿和洛山矶的中间，或者就在附近。）小行星必须在上升到黑夜中的地平线上10度以上才能较准确的定位。我们的计划是按照小行星中心8月11号得到的天文测量数据制定的。每一个数据都是很准确的！但小行星在前进的过程中与计划总是有1到2分钟的差别的。
为了更好的观察这个小行星，更好的观察它的细节你应该制定详细的计划。你应该提前10分钟将你的望远镜对准它将出现的位置等待。如果你错过了，你应该找另外一个更远的点再次寻找。
考虑它在你的视野中在星空中是很暗的，但它在小望远镜中仍然是很容易看到的。起码有24小时的时间你能够观测它，可是它会跑到相对地基望远镜上空即很靠近太阳的哪个方向。


原文：Where and How to Look

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When the asteroid is closest to Earth at around 7:47 UT on the 18th, it will be traveling eastward at a breezy 8 arcminutes per minute!


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On the night of Saturday, August 17–18, 2002 NY40 should reach magnitude 10 or even 9 during the period when it is well placed for viewing from Europe, Africa, and the Americas. Although it might be spotted in binoculars, small telescopes should give a more satisfying view by magnifying the object抯 apparent motion. Skywatchers should be able to perceive this motion any time it glides near a background star. When the asteroid is closest to Earth at around 7:47 Universal Time on the 18th, it will be traveling eastward at a breezy 8 arcminutes per minute!

For help in locating the asteroid that night, Sky & Telescope has prepared four finder charts (A, B, C, and D) that span a 60° arc across the heavens from Sagitta through Vulpecula, Cygnus, Lyra, and Hercules. Each chart is a PDF file; these are readable on any computer using Adobe's free Acrobat Reader software, version 3.0 or later, and can be printed out for use at the telescope.

Chart A is mainly of use to observers in Europe and Africa, with tracks plotted for the period 20:00 UT (on the 17th) to 01:30 UT on the 18th.

Chart B includes the start of tracks suitable for North American viewers, plotted from 1:30 to 4:30 UT.

Chart C shows the continuation of the asteroid抯 path as viewed from Boston and Los Angeles between 4:10 and 6:10 UT.

Chart D shows the the final portion of the track for North American viewers and concludes at 7:40 UT.

Because of the parallax effect, the asteroid抯 exact trajectory depends on your geographical location. Tracks for several widely separated cities are shown, and you can estimate the track for your own location relative to those shown. (For example, the track for Denver would lie between the tracks shown for Boston and Los Angeles, somewhat nearer the latter.) Each plotted track covers only the period when the asteroid is at least 10° above the horizon in a fully dark sky at that location. Our plots are based on astrometric measurements received by the Minor Planet Center through August 11th. Each individual track should be quite reliable, but the object抯 arrival time at a specific point along a track is still uncertain by 1 or 2 minutes.

To catch sight of this fleet visitor, the best strategy is to pick out a star near which the asteroid will pass at a specific UT. About 10 minutes in advance, park your telescope on that star and watch for the asteroid to come by. If you miss it, find another plotted star farther down the track and try again.

Keep in mind that the asteroid will be slightly fainter than the stars shown in our plots, yet still quite easy to see in a small telescope. A mere 24 hours after it goes by, however, the object will plunge hopelessly beyond reach of Earth-based telescopes as it heads closer to the Sun. (We will then be viewing its unilluminated side, which explains why it becomes so faint, so fast.)