Exposure Time and Star SelectionThe

Exposure Time and Star Selection
The guide star can be selected (clicked on) while "looping" is active - in fact, this is the recommended method. It can also be selected after looping has been stopped, but this opens the possibility that the star might have moved since the last exposure. No great precision is required in clicking on the star - PHD2 will find the star nearest to the cursor. After you do this, a green box will appear to frame the star. If you pick a star that is too bright, a message box will tell you the star is "saturated", and you should either use a different star or decrease the exposure duration. The choice of exposure time will depend entirely on your equipment, sky conditions, and the available stars. The exposure time you choose has two major implications:
1.
It affects the signal strength (brightness) of the selected star - a brighter star will stand out better from the background and will generally produce better guiding results so long as it is not saturated.
2.
It also determines the frequency with which guide commands are sent to the mount - guide commands cannot be sent any more frequently than once for each exposure cycle. Some mounts benefit from frequent small guiding adjustments while others do not - you may need to experiment to understand what works best for your situation.
As a starting point, try using exposure durations in the range of one to five seconds. Rather than choosing the star yourself with a mouse-click, you can let PHD2 Auto-select the guide star by using the Alt-S keyboard shortcut after stars are visible in the main display.
There is also an Auto exposure time selection available. When exposure is set to Auto, PHD2 will attempt to adjust the exposure to keep the selected guide star at a constant signal-to-noise ratio (SNR) value. The Auto setting can be especially beneficial for AO users who want to minimize exposure time without losing the guide star. The settings to control Auto-exposure are on the Global Tab of the Advanced Dialog.
Automatic Calibration
Conventional Mounts
Two things need to be measured by PHD2 as part of guider calibration:
1.
The angle of the camera relative to the telescope axes
2.
The length of the guide pulse needed to move the telescope by a specific amount
PHD2 handles these measurements automatically by sending guide pulses to the mount and "watching" how far and in which direction the star moves between guide camera images. This process begins after you have selected a star and then clicked on the Guide icon button. Yellow cross-hairs will appear over the original location of your guide star and PHD2 will start to move the mount in various directions, tracking how the star moves as a function of what move commands were sent to the mount. The status bar will display the commands as they are sent to the mount, along with the incremental movements of the guide star relative to its starting position. PHD2 will do this on both axes, first moving east and west, then north and south. PHD2 wants to move the star up to 25 pixels in each direction in order to get an accurate calibration. Once this is complete, the crosshairs will turn green and guiding will start automatically..
In most cases, calibration will complete automatically without any user involvement. Obviously, this assumes that the mount and all the cable connections are working correctly. If they are not, the calibration is likely to fail with a message that the "star did not move enough"; and you'll need to do some trouble-shooting. If the star has basically not moved at all in one or more directions, you should look first at the cable connections and mount behavior. The "manual guide" function under the 'Tools' menu can help with this as can the trouble-shooting section of this document. But if the star has moved by some amount in each direction, you may need to adjust a calibration setting called the calibration step-size. PHD2 uses this parameter during calibration as a fixed-size duration of movement. The default value has been chosen to cover a wide range of typical guide scope set-ups, but you may need to adjust it for your situation. For example, an off-axis-guider on a long focal length scope will probably need a setting that's different from the default value. To adjust it, go into the "brain dialog" (Advanced Settings) and click on the 'Mount' tab. On that tab, you'll find a setting for 'Calibration step(ms)', and that's where you change the value. There's even a 'Calculate' button that will help you choose an optimal value for the parameter. Once you've set this value, it will be remembered as part of your equipment profile and you probably won't have to adjust it again.
You may also see a calibration failure if you're using a star too close to the celestial pole. In those locations, fixed-length movements in right ascension often move the star only a very small distance. In that case, move to a star location closer to the equator, ideally somewhere in the range of -30 to +30 degrees declination, and re-run the calibration. But if this is not feasible, you can adjust the calibration step-size upward until calibration succeeds.
Like all other guide settings, the calibration data is automatically saved as part of your current equipment profile. If nothing has changed in your configuration from one session to the next - even over an extended time period - you can restore the previous calibration data and start guiding immediately. This function is located under the 'Tools' menu and is labelled 'Restore Calibration Data.' Remember, the data are saved whenever a full calibration is completed or when you use the 'flip calibration data' command under the 'Tools' menu (see below). If you're using a German equatorial mount and the ASCOM interface or you have an 'aux' mount connected, the saved calibration data will include the side of pier where you were last guiding; so PHD2 will adjust automatically for your current pointing position. But if you are not using mount interfaces that can return pointing information, you'll need to remember which side of the pier was being used the last time you were guiding.
If you're using an ASCOM mount (or 'aux' mount) connection, PHD2 will also include the calibration and target declinations as part of its calculations. In that case, guiding moves in right ascension will be automatically adjusted to account for the declination of the current guide star, as opposed to the star you used for calibration. This is really just a refinement and isn't critical in most situations, so absence of pointing information is not a big problem. However, if you are concerned about it and are imaging near the celestial pole, you should consider calibrating using a star that's also at high declination.
After a calibration is completed, PHD2 will "sanity check" the results to be sure the calculations at least look reasonable. If they don't, you will see an 'alert' message at the top of the main window that describes the calibration result that looks questionable. You can choose to ignore the alert or click on 'Details' to get more information. It is generally advisable to pay attention to these alerts because there is no point in trying to proceed using calibration results that are significantly in error.
Adaptive Optics Devices
If you are using an adaptive optics device, there are actually two calibration processes that must complete. The first handles calibration of the tip/tilt mirror in the AO and calculates the magnitude and direction of the adjustments as they relate to displacements of the guide star. The second calibration is the one described above, dealing with guide commands that need to be sent to the mount. Known as "bump" commands, these will be issued when the guide star has moved beyond the range of corrections that can be achieved with the AO alone.
Guiding
Once guiding has begun, diagnostic messages will be displayed in the status bar to show what guide commanda are being sent to the mount. PHD2 will continue guiding until you click on the 'stop' icon. To resume guiding, simply start looping exposures again, select your star, and click on the 'Guide' button. You will not need to repeat the calibration in order to resume guiding. In some cases, PHD2 may "lose" the guide star and you'll be alerted by an audible beep and flashing orange crosshairs. There are several reasons this might occur:
1.
Something may be obscuring the star - clouds, the observatory roof, a tree, etc.
2.
The star may have abruptly moved out of the tracking rectangle because something shifted in the mount/camera/cabling infrastructure - cable "snags" often cause this
3.
The star may have "faded" for some other reason, perhaps because it is overly faint
Obviously, you'll need to identify the source of the problem and fix it. However, it's important to understand that PHD2 will not start moving the telescope around in an attempt to relocate the guide star. It will simply continue to take exposures and look for the guide star to reappear within the bounds of the current tracking rectangle. When you first start guiding, you may see an 'alert' dialog at the top of the window if no dark library or bad-pixel map is being used. You can choose to ignore this warning and continue with guiding, but you are likely to get better results if you spend the few minutes needed to construct a dark library for future use.
If you are using a German equatorial mount (GEM), you will usually have to do a "meridian flip" around the time your image target crosses the meridian. This means you will move the telescope around to the opposite side of the pier and then resume imaging. Doing this invalidates the original calibration, typically because the declination directions are now reversed. If you are using an ASCOM (or 'aux' ) mount interface, your calibration will be adjusted automatically and you can simply resum

結果 (中文) 1:

Exposure Time and Star SelectionThe guide star can be selected (clicked on) while "looping" is active - in fact, this is the recommended method. It can also be selected after looping has been stopped, but this opens the possibility that the star might have moved since the last exposure. No great precision is required in clicking on the star - PHD2 will find the star nearest to the cursor. After you do this, a green box will appear to frame the star. If you pick a star that is too bright, a message box will tell you the star is "saturated", and you should either use a different star or decrease the exposure duration. The choice of exposure time will depend entirely on your equipment, sky conditions, and the available stars. The exposure time you choose has two major implications: 1. It affects the signal strength (brightness) of the selected star - a brighter star will stand out better from the background and will generally produce better guiding results so long as it is not saturated. 2. It also determines the frequency with which guide commands are sent to the mount - guide commands cannot be sent any more frequently than once for each exposure cycle. Some mounts benefit from frequent small guiding adjustments while others do not - you may need to experiment to understand what works best for your situation. As a starting point, try using exposure durations in the range of one to five seconds. Rather than choosing the star yourself with a mouse-click, you can let PHD2 Auto-select the guide star by using the Alt-S keyboard shortcut after stars are visible in the main display. There is also an Auto exposure time selection available. When exposure is set to Auto, PHD2 will attempt to adjust the exposure to keep the selected guide star at a constant signal-to-noise ratio (SNR) value. The Auto setting can be especially beneficial for AO users who want to minimize exposure time without losing the guide star. The settings to control Auto-exposure are on the Global Tab of the Advanced Dialog. Automatic CalibrationConventional MountsTwo things need to be measured by PHD2 as part of guider calibration: 1. The angle of the camera relative to the telescope axes 2. The length of the guide pulse needed to move the telescope by a specific amount PHD2 handles these measurements automatically by sending guide pulses to the mount and "watching" how far and in which direction the star moves between guide camera images. This process begins after you have selected a star and then clicked on the Guide icon button. Yellow cross-hairs will appear over the original location of your guide star and PHD2 will start to move the mount in various directions, tracking how the star moves as a function of what move commands were sent to the mount. The status bar will display the commands as they are sent to the mount, along with the incremental movements of the guide star relative to its starting position. PHD2 will do this on both axes, first moving east and west, then north and south. PHD2 wants to move the star up to 25 pixels in each direction in order to get an accurate calibration. Once this is complete, the crosshairs will turn green and guiding will start automatically.. 在大多数情况下，校准将自动完成没有任何用户干预。很明显，这是假定装载和所有的电缆连接工作正常。如果他们不是，校准很可能会失败的消息，"明星没有移动不够"；和你需要做一些故障排除。如果这位明星已基本上不受感动，在一个或多个方向，你应该首先看看的电缆连接和安装行为。在工具菜单下的"操作指南"功能可以帮助这，可以此文档的故障排除部分。但如果这位明星已由一定数量在每个方向移动的你可能需要调整一个叫做校准步长的校准设置。PHD2 在校准期间使用了此参数，作为与图像组大小固定移动的持续时间。已被选定的默认值，以涵盖广泛的典型指南范围设置，但您可能需要调整您的实际情况。例如，离轴-导引头上长焦距范围将可能需要一个不同于默认值的设置。若要调整它，进入"大脑对话框"（高级设置），然后点击装载选项卡。在该选项卡上，你会发现一个设置为 '校准 step(ms)'，这是在哪里，您更改的值。甚至还有一个计算按钮，将帮助您选择参数的最优值。一旦您设置此值，它将作为您的设备配置文件的一部分被铭记，你大概不会有再次调整。You may also see a calibration failure if you're using a star too close to the celestial pole. In those locations, fixed-length movements in right ascension often move the star only a very small distance. In that case, move to a star location closer to the equator, ideally somewhere in the range of -30 to +30 degrees declination, and re-run the calibration. But if this is not feasible, you can adjust the calibration step-size upward until calibration succeeds.Like all other guide settings, the calibration data is automatically saved as part of your current equipment profile. If nothing has changed in your configuration from one session to the next - even over an extended time period - you can restore the previous calibration data and start guiding immediately. This function is located under the 'Tools' menu and is labelled 'Restore Calibration Data.' Remember, the data are saved whenever a full calibration is completed or when you use the 'flip calibration data' command under the 'Tools' menu (see below). If you're using a German equatorial mount and the ASCOM interface or you have an 'aux' mount connected, the saved calibration data will include the side of pier where you were last guiding; so PHD2 will adjust automatically for your current pointing position. But if you are not using mount interfaces that can return pointing information, you'll need to remember which side of the pier was being used the last time you were guiding.If you're using an ASCOM mount (or 'aux' mount) connection, PHD2 will also include the calibration and target declinations as part of its calculations. In that case, guiding moves in right ascension will be automatically adjusted to account for the declination of the current guide star, as opposed to the star you used for calibration. This is really just a refinement and isn't critical in most situations, so absence of pointing information is not a big problem. However, if you are concerned about it and are imaging near the celestial pole, you should consider calibrating using a star that's also at high declination.After a calibration is completed, PHD2 will "sanity check" the results to be sure the calculations at least look reasonable. If they don't, you will see an 'alert' message at the top of the main window that describes the calibration result that looks questionable. You can choose to ignore the alert or click on 'Details' to get more information. It is generally advisable to pay attention to these alerts because there is no point in trying to proceed using calibration results that are significantly in error.Adaptive Optics DevicesIf you are using an adaptive optics device, there are actually two calibration processes that must complete. The first handles calibration of the tip/tilt mirror in the AO and calculates the magnitude and direction of the adjustments as they relate to displacements of the guide star. The second calibration is the one described above, dealing with guide commands that need to be sent to the mount. Known as "bump" commands, these will be issued when the guide star has moved beyond the range of corrections that can be achieved with the AO alone. GuidingOnce guiding has begun, diagnostic messages will be displayed in the status bar to show what guide commanda are being sent to the mount. PHD2 will continue guiding until you click on the 'stop' icon. To resume guiding, simply start looping exposures again, select your star, and click on the 'Guide' button. You will not need to repeat the calibration in order to resume guiding. In some cases, PHD2 may "lose" the guide star and you'll be alerted by an audible beep and flashing orange crosshairs. There are several reasons this might occur: 1. Something may be obscuring the star - clouds, the observatory roof, a tree, etc. 2. The star may have abruptly moved out of the tracking rectangle because something shifted in the mount/camera/cabling infrastructure - cable "snags" often cause this 3. The star may have "faded" for some other reason, perhaps because it is overly faint Obviously, you'll need to identify the source of the problem and fix it. However, it's important to understand that PHD2 will not start moving the telescope around in an attempt to relocate the guide star. It will simply continue to take exposures and look for the guide star to reappear within the bounds of the current tracking rectangle. When you first start guiding, you may see an 'alert' dialog at the top of the window if no dark library or bad-pixel map is being used. You can choose to ignore this warning and continue with guiding, but you are likely to get better results if you spend the few minutes needed to construct a dark library for future use.If you are using a German equatorial mount (GEM), you will usually have to do a "meridian flip" around the time your image target crosses the meridian. This means you will move the telescope around to the opposite side of the pier and then resume imaging. Doing this invalidates the original calibration, typically because the declination directions are now reversed. If you are using an ASCOM (or 'aux' ) mount interface, your calibration will be adjusted automatically and you can simply resum

結果 (中文) 3:

曝光时间和明星选择
引导星可以选择（点击）而“循环”是积极的-事实上，这是推荐的方法。它也可以在循环已经停止选择，但这将打开星可能自去年曝光移动的可能性。没有伟大的精度在点击星所需的专业会找到最接近光标的明星。之后，一个绿色的盒子会出现帧星。如果你选择一个明星，太亮，将出现一个消息框，告诉你明星是“饱和”，你应该使用一个不同的星球或减少曝光时间。曝光时间的选择完全取决于你的装备，天空状况，和现有的明星。你选择的曝光时间主要有两层含义：
1。
影响信号强度（亮度）的选星-一个明亮的恒星会从背景中突出更好，通常会产生更好的指导的结果，只要是不饱和的。
2。
也决定频率与导命令发送到安装向导命令不能发出任何多于每一次曝光周期。一些坐骑指导调整频繁的小利益而不是别人-你可能需要实验来了解什么是最适合你的情况。
为出发点，尝试在一至五秒的范围内使用的曝光时间。而不是选择的明星自己用鼠标点击，你可以让专业的自动选择后，恒星在主显示可以使用键盘快捷键导星alt-s。
还有一个自动曝光时间的选择。当曝光设置为自动，PHD2将尝试调整曝光，以保持选定的导星在一个恒定的信噪比（SNR）值。自动设置可以为那些想不失导星减少曝光时间AO用户特别是有益的。控制自动曝光的设置在“高级”对话框的全局表。
自动校准
常规坐骑
两事情需要用专业的向导校准部分：
1。
摄像机的角度相对于望远镜轴
2。
需要的具体金额
移动望远镜专业指导脉冲长度处理这些测量结果自动发送导脉冲山和“看”有多远，在哪个方向星指南相机图像之间移动。这个过程后，你选择了一个明星，然后点击向导图标按钮开始。黄十字会出现在你的导星和PHD2原始位置将开始在各个方向移动安装，如何跟踪星移为什么移动指令的功能被送到山。状态栏将显示命令，他们被送到山，随着导星相对其起始位置的增量移动。专业将轴做这个，第一个移动的东西，然后南北。专业要移星到25像素为每个方向要准确标定。一旦完成，十字线会变绿和指导会自动启动的。
在大多数情况下，校准将自动完成而不需要用户的参与。很明显，这假定安装所有电缆连接是否正常工作。如果他们没有，校准是可能失败的一个消息，“明星不动足”；你需要做一些故障排除。如果恒星已经基本上没有在所有移动一个或更多的方向，你应该先看看电缆连接和安装行为。“指南手册”功能，在“工具”菜单可以帮助这可以排除本文件的部分。如果恒星已经由一定数量的每个方向，你可能需要调整校准设置校准步长。专业使用这个参数校准过程中的一个固定大小的时间运动。默认值选择了涵盖范围广泛的典型引导范围设置UPS，但你可能需要调整你的情况。例如，一个离轴导向器在长焦距范围可能需要设置不同的默认值。调整它，进入“脑对话”（高级设置），在“安装”选项卡，单击。在此选项卡，你会发现一个设置的校准步骤（MS）”，这就是改变你的价值。甚至还有一个“计算”按钮，将帮助您选择的参数的最优值。一旦你设置此值，它将被作为你的设备的配置文件的一部分，你可能不会再调整
。你也可以如果你用星太接近天极看校准失败。在这些地点，固定长度的运动经常运动的赤星只有一个非常小的距离。在这种情况下，移动到一个星的位置接近赤道，理想的范围在30到30度-偏角，并重新运行校准。但如果这是不可行的，你可以调整校正步长向上直到校准成功。
像所有其他指南设置，校准数据自动保存您当前的设备配置文件的一部分。如果没有改变你的配置从一个会议到下一个-甚至在较长的时间内，你可以恢复以前的校准数据并立即开始指导。本功能位于“工具”菜单下的标签是“恢复校准数据。记住，数据保存在全校准完成后或当您使用“翻转校准数据”命令下的“工具”菜单（见下文）。如果您使用的是德国赤道和基带接口或你有一个AUX安装连接，保存的校准数据包括墩你上次指导方；所以专业会自动调整为当前指向的位置。但如果你不使用的安装界面，可以返回指向信息，你需要记住的码头边被你上次指导使用。
如果你使用ASCOM安装（或AUX安装）连接，专业还包括校准和目标偏角的计算。在这种情况下，指导移动在正确的提升会自动调整到当前的导星的赤纬，而你用于校准的明星。这是真的只是一个细化和不是在大多数情况下的临界，因此，指向信息的缺乏是不是一个大问题。然而，如果你关注它，成像天极附近，你应该考虑使用一个明星，也是校准高偏角。
后校准完成后，将“专业性检查”的结果是肯定至少看起来合理的计算。如果他们不，你将在那描述的校准结果看起来可疑的主窗口的顶部看到一个“警告”的消息。你可以选择忽略警告或单击“详细信息”以获得更多的信息。它通常是可取的，注意这些警告是因为在试图进行校准的结果是显着的误差自适应光学器件

点。如果您使用的是自适应光学装置，其实有两个校准过程中，必须完成。第一处理校准的倾斜镜在AO计算调整幅度和方向与位移的导星。第二校准是一所述，处理引导命令需要被发送到山上。被称为“凸点”命令，这时会发出导星已经超越了更正，可与AO单独实现的范围。

一旦开始指导指导，诊断信息将显示在状态栏中显示什么引导康美达契约被送到山上。专业将继续指导直到你点击“停止”图标。简历指导，只是开始循环暴露了，选择你的明星，并在“向导”按钮。你不需要重复校准为了简历指导。在某些情况下可能会“失去”，专业的导星和你的嘟嘟声和闪烁的红色十字提醒。有几个原因这可能发生：
1。
事情可能掩盖的恒星云，天文台屋顶，一棵树，
2等。
明星可能突然移动的跟踪矩形是由于安装/摄像头/综合布线基础设施电缆“阻碍”会
3移。
明星可能会“消失”的其他原因，可能是因为它过于微弱
显然，你需要找出问题的根源并解决它。然而，了解专业不会开始移动望远镜在尝试重新定位导星是很重要的。它只会继续采取风险和寻找导星出现在电流跟踪矩形边界。当你第一次开始指导，你可能会看到一个“警告”对话框窗口顶部的如果没有黑暗图书馆或坏像素地图被使用。你可以选择忽略这个警告，继续指导，但你可能如果你需要构建未来使用一个黑暗的图书馆几分钟得到更好的结果。如果您正在使用
德国赤道（GEM），你通常会做一个“子午翻转”周围的时候，你图像目标穿越子午线。这意味着你将望远镜在码头的对面，然后恢复成像。做这种无效的原始校准，通常是因为赤纬方向现在颠倒过来了。如果您使用的是亚斯康（或AUX）安装界面，您的校准将自动调整，你可以简单的简历