Phd guiding 漂移法对极轴(非常高效)

传统的用十字目镜要等上一段时间才能判断星星的漂移，不够高效。今天看到一篇文章介绍用phd来漂移对极轴感觉很有效。当然专门的通过电子目镜漂移法对极轴软件也有，但是感觉没phd这个来的方便。

简单归纳一下就是以下3个步骤
1.粗对极轴
2.水平微调RA，选一个Meridian附近并且dec=0° （原文是elevation，根据漂移法原理应该是dec=0°）的星星，让phd校准然后关掉dec的修正观察dx/dy图。通过看dy的偏移来向左或者向右水平微调RA轴直到dy没有变化。
3.垂直微调RA，选一个东面或者西面地平线附近的星星，离地平线的高度越低漂移会越明显。同样重新校准phd然后关掉dec的修正观察dx/dy图。通过看dy的偏移来向上或者向下垂直微调RA轴直到dy没有变化。

希望对大家有用....

原文：
Drift Alignment Using PHD Guiding Software:

Just recently an acquaintance ( Ted Rafferty) put me on to  doing the drift alignment using the popular auto guiding program (PHD) available for free at Stark-Labs.
The process begins as all the other drift alignments. To check the RA alignment chose a star at 0° elevation close to  the meridian. To set the DEC alignment choose a star as close to  the E or W horizon as possible.

    Turn on the guiding program (PHD) , select the mount and camera and run thru your  calibration a usually.
    To Check the RA select a star near the Meridian at 0° elevation.
    Start Guiding on the selected star.
    Turn on the GRAPH and select DX/DY instead of RA/DEC.
    Turn off the DEC guiding
    If your mount is perfectly aligned the DY ( red line) should track across the graph near the center line. If it drift up  or down you  need to  make a very small adjustment to your AZIMUTH screws to compensate for that. You  will see the change immediately. No need to  wait 5 or 10 minutes for the visual drift.
    Now set up  the elevation.
    Stop the guiding and look for a star near the western or eastern horizon at whatever elevation allows you to clear any obstruction. The lower the better.
    Recalibrate the guiding on the new star.
    As in step 3,4 & 5 above start guiding and make sure that  the DEC guiding is off.
    Once again if your alignment is on then the DY trace should not drift from the horizontal graph line. If it does, carefully mar small adjusts to the ELEVATION screws to compensate. Again you should see an immediate change in the graph.

This process is simple enough to allow you to check you  polar alignment whenever you  feel it necessary. The only requirement is that  you  get a copy of PHD and have a camera that  is supported by the program ( there are many).

好帖子，好方法，顶一下.

回家也试试

使用QHY5和QHY6发现，PHD里找比较暗的星真的很难。

使用QHY5和QHY6发现，PHD里找比较暗的星真的很难。
后心发冷 发表于 2011-5-20 12:27

                               
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    qhy不能调节曝光时间吗？曝光时间调到1秒以上短焦中等口径的导星镜上任何星区找引导星应该没有任何问题吧。

嗯同样的调节参数，同样的GAIN值和曝光时间，用文佳60220,PHD的屏幕上只有2颗星，MDL5上，有不少于7~8颗。

学习了，不过我不懂呵呵，保存下来，等以后能用得到~

学习了，
或者以后有用哈。