In this tutorial, the position of an asteroid is measured in a pair of images. Basic astrometry will also work with a single image (for example, if you want to measure the precise position of a star or supernova). However, we will use two images here, which helps us to identify the moving asteroid by blinking the frames.
在本指南中，在两张图片中有一个共同的已知的小行星被测量到，基本天文测量也可以被用于单一的一张图片（比如：你可以准确的测量一颗或超新星的位置），在此，我们将使用两张，从而通过播放动画来确定一个移动的小行星。
1. Loading the Images 载入图片
Use the 'Load Images' command from the 'File' menu to load the two images '2000AC6_1.st6'
and '2000AC6_2.st6'. Load the images either one by one, or use multiple selection
in the file dialog (by holding down the [Ctrl] key while clicking on the image
files) to load them at once. After each image has been loaded, the software
asks you to verify (and eventually correct) the date and time it has read from
the image file header before it displays the image. The software expects that
the time entered here is the Universal Time (UT)
of mid-exposure, good to the nearest second. The time stored in the file header
of the demo images is correct, so you just need to accept the values shown.
使用“File”菜单中的“Load Images”命令载入 '2000AC6_1.st6' 和'2000AC6_2.st6'两张图片， 你可以一张一张的载入，也可以使用Ctrl键一次性载入多张图片。每张图片载入后，软件都会弹出窗口核实图片的拍摄日期和时间。软件希望用户确认的时间是暴光中点时刻的时间，使用世界时，最好精确到秒级。本例中的两张演示图片的时间是准确的，所以你只需要点确定接受就可以了。
2. Blinking the Images 动画图片
From the 'Tools' menu, select the 'Blink Images' command. The software will
align and blink the images. Use the Blink Toolbar to set the blink frequency,
to stop blinking, to switch manually between the images, or to restart blinking.
For example, you can stop blinking once you have located the asteroid, and to
place the mouse cursor over the image of the minor planet. The coordinates of
the pixel under the crosshairs will be displayed in the status line at the bottom
of the main window. You can use these coordinates to locate the asteroid later.
Close the Blink Window after you have identified the asteroid.
在“Tools”菜单中选择“Blink Images”命令，本软件将会排列并动画循环图片，使用动画工具条可以设置动画的频率、停止动画、手动翻转前一张和后一张以及重新启动动画。比如：当你确定一个小行星后，你可以停止动画，将鼠标十字指针定位在小行星上，在主窗口的底端的状态条上就会显示出十字指针处的像素坐标，你可以过后通过这些坐标来定位小行星。在你确定了这颗小行星后就可以关闭动画窗口了。
3. Astrometric Data Reduction 天文数据分类
Select the 'Data Reduction' command from the 'Astrometry' menu. The software
will ask you to enter either the coordinates at which the images are centered,
or the designation of the object on the images, so it can compute these coordinates
(assuming that the images are centred on the target). Enter '2000AC6' in the
'Object' field. (The software will search for a designation that starts with
the characters you enter here. Note that, if you search for a numbered minor
planet, you must include at least the leading parenthesis. For long-period and
unnumbered short-period comets, you must include the 'C/' and 'P/', respectively.
Blanks in the designation of the object are not significant, and there is no
differentiation between lower- and uppercase letters.) When the cursor leaves
the field (for example, after pressing the tab [Tab] key) the coordinates calculated
for the object will appear. Alternatively, you may enter the coordinates as
shown in the screenshot below. Another possibility to select the object, the
object browser, is described in Tutorial II.
在“Astrometry”菜单中选择“Data Reduction”，软件将请你输入图片中心点坐标或图片中天体的名称，从而使软件可以计算这些坐标（假定图片已经被居中），在“Object”中输入“2000AC6”（这个软件将搜索你以字符形式输入的恒星名称，注意，如果你搜索的是一个命名的小行星，你必须至少包括圆括号，对于长周期和未命名的短周期彗星，你必须包括“C/”和“P/”，名称中的空格并不重要，也不区分大小写）当鼠标指针移离这个区域（比如：在你按下Tab键后），坐标核算就会开始出现，同样地，你也可以像在如下屏幕截图中所示那样输入坐标，另一种可能的选择目标的方式——目标浏览器，在指南2中介绍。
Pressing the [OK] button will start the astrometric data reduction process. After a while, colored circles will be drawn around the objects detected by the software:
点OK后，天文数据分类将会开始，过一会儿，软件识别后的结果就会以彩色圈的形式显示出来：
在天文数据分类中参考星以绿圈形式显示，由于与参考星所提供的数据差异太大而被定义的“无用”参考星以黄圈形式显示。
至少在两幅图中的同一位置发现的目标（恒星）以蓝色形式显示。
手动测量的目标（见下）将以紫色圈形式显示。
其他的检测目标以灰色圈表示，这些目标或者是移动的，或者是非常暗弱的假目标以至于软件不能在所有的图片中检测到，或者是类似于恒星的噪点。
Note: If you have measured a single image, stars will also be circled grey, because the software has no other image on which it can check if a certain detection appears at the same position. Also note that the colors listed above refer to the default settings. The colors can be changed in the Program Settings, resulting in different color coding.
注：假如你检测一幅图片，恒星也会以灰圈表示，因为软件无法通过一张图片的一个位置来确定星星的身份。以上的各种颜色的定义都是软件默认的，你可以在Program Settings中设置不同的颜色。
在主界面的右下角（如上图），通过一个弹出窗口给出了一些重要资料的简单预览，除图片的文件名外，列表中给出了每张图片中的恒星数目及参考星的数目，后续的列表中显示了被用于天文数据分类的参考星的数量及这些星的测量偏差（以角秒表示），还有用于照相光度的参考星的数目及星等的测量偏差。
4. Measuring the Object 测量目标
Measuring the position of any object on the images is now very easy - simply
by clicking on it. It may be of some help if you open the Magnifying Window
using the appropriate command in the 'Tools', or the toolbar button. Now move
the crosshairs precisely over the asteroid (or any other object in the image
you want to measure) and click on it. A verification dialog will open that displays
a zoomed section of the image, centered on the object you clicked on. Below
that image is a combo box where you can choose the zoom level (the other two
combo boxes are not used here - they are described in Tutorial
II), and the file name of the image, as well as the coordinates and the
magnitude of the object are displayed. To the right, two graphs shows the point
spread function (PSF) fitted to the pixel data,
and the residuals of that fit. Below these graphs, some data from the fit are
displayed: The location of the centroid
(pixel coordinates), the SNR of the brightest
pixel, the total flux, the FWHM
of the PSF (in arc seconds), and the RMS
residual of the fit.
通过点击鼠标可以很轻松地测得图片上任何目标的位置。如果使用“Tools”菜单中的“放大窗口”功能或使用相应的工具条按钮，可能对测量有帮助。现在请移动十字鼠标指针，使其正好指向小行星（或其他任何目标）并点击它，一个确认对话框将打开，上面显示了一个以你点击位置为中心的经过放大的图片截图，在该图片之下有一个可以选择放缩程度下拉框（另两个下拉框在这里不可用——在指南2将有介绍）、图片的文件名及目标的赤经纬坐标和星等。在右边两个小图显示了被测点的点扩展函数曲线（对应到像素情况）及偏差量。在这两幅小图下面是相应数据的显示：最佳测量点像素坐标，最亮点的信噪比，总光通量，点扩展函数的半最大值宽度（以角秒表示），对应点的均方根误差。
Enter the packed designation of the object ('K00A06C' for 2000 AC6) in the Object Designation field, and press the [Accept] Button to store the measured position. Note that the object is now marked with a pink circle on the image.
在目标名称指定框输入目标的国际标准名称（对于2000 AC6输入“K00A06C”），并点击Accept按钮用以储存测量位置，请注意这个目标现在将以紫色圈标明。
Tip: Pressing the browser button [...] in Object Designation field of the the Verification Window will bring up the Object Identification Dialogue which displays all known asteroids and comets near the measured positions, supporting identification of the object.
技巧：在确认窗口的目标指定区域中点击浏览按钮[...]，将给出目标身份对话框，里面显示了在测量位置附近的所有已知的小行星和彗星，用以帮助确定目标。
Tip: When you click on the image to measure an object, the software will automatically center on the brightest pixel near the point where you clicked (i.e., the brightest pixel within the Aperture Radius specified in the Program Settings). However, if you hold down the [Ctrl] while clicking on the image, the software will calculate a simple centroid (no PSF-fit) centered exactly on the pixel you clicked on: This might be useful if you try to measure an object that is close to a star, or an object in a dense star field. As another option, you can press both the [Shift] and [Ctrl] key, and the software will just take the coordinate of the pixel over which the cursor is located, whithout any centroiding. Also note that you can move the cursor over the image using the arrow keys on the keyboard, and use the [Enter] key instead of the mouse button for 'clicking'.
技巧：当你点击图片上的目标用以测量时，软件将在你点击的位置附近自动定位到最亮的一个像素（在程序设置中可详细设定最亮点的搜索像素半径），然而，如果你按住Ctrl键并点击图片，软件将在你点击的位置附近做简单的质心定位（非点扩展函数方式），这可能在试图测定一个比较靠近恒星的目标时或在恒星密集区有用。另一种选择是：你可以同时按住Ctrl和Shift键，软件将不做任何质心处理，提取鼠标尖端的坐标。你还可以使用方向键来代替鼠标的移动，用Enter键代替鼠标左键单击。
Tip: After data reduction has been performed on the individual frames, you can also measure the position of any object in the blink window, again by clicking on it. It's probably a good idea to stop blinking, measure one position, and then proceed to the next image in the sequence, using the respective buttons in the toolbar.
技巧：当对单一一张图片数据分类执行完毕之后，你可以继续使用鼠标在动画窗口中测量另外一些目标的位置，但最好是关闭动画，测量一个位置，然后翻转到下一张，在工具条中使用相关的按钮。
5. Viewing the Results 查看结果
Select the 'View MPC Report' command from the 'File' menu to display the results
as saved to the file MPC Report file
('MPCReport.txt'). This file holds the results of the data reduction in
a standarized format that will be accepted by the MPC.
Select the 'View Log File' command to browse Astrometrica's Log
File ('Astrometrica.log') file that includes detailed information, like
the positions, magnitudes and residuals for all reference stars.
在File菜单中选择View MPC Report命令，可以显示MPCReport.txt文件的内容，在这个文件中记载着能被MPC接受的标准化的数据分类结果。选择“View Log File”命令可以浏览Astrometrica.log文件，该文件包含各种操作细节，比如：位置、星等及所有参考星的偏差。
Tip: Upon startup, the software asks you if you want to replace the MPC Report and/or the Log file, if they already exist. If you want to append the new results to the existing files, choose 'No'. You can reset the contents of these files at any time by choosing the 'Reset Files' command in the 'File' menu.
技巧：在启动本软件时，软件会询问是否覆盖MPC文件和/或Log文件（如果它们都已经存在）。如果你打算继续添加新的测量结果到原来的文件中，请选择“NO”。选择File菜单里的“Reset Files”命令，你可以在任何时候重新设置这些文件的内容。
6. Sending the Results to the MPC 向MPC发报告
If your computer is connected to the Internet, you could send the contents of
the file 'MPCReport.txt' directly to the MPC
using the 'Send MPCReport' command from the 'Internet' menu.
Please do not send the results of these Tutorials or of any other tests to the
MPC !
如果你的电脑已经连接到国际互联网，使用“Internet”菜单中的“Send MPCReport”命令，你可以将MPCReport.txt文件中的内容直接发送到MPC。请不要发送本指南中的结果或其他测试到MPC！