是否極軸對不準
用TPoint recheck
發現都是很準
Daniel認為我的導星一直往RA(-X)方向做非線性移動
故不是極軸對不準
To clarify this statement, depending on the values of ME and ME and the star's position, polar misalignment can cause drift in any direction. Polar misalignment will not cause a nonlinear motion in right ascension. Periodic error will.
我說下次會好好確認極軸有沒有跑掉
Patrick Wallace 也認為不是極軸對不準的問題
I doubt if that's your problem. You need to train your PEC.
我做了pec 但發現作了更差
pec_on
pec_off
有人質疑我方向搞錯會更差
但我做了 image link確定方向是對的（北上東右）
有人認為還有其他機械性因素
One issue that that would worry me is whether the dirft continues in the same direction, possibly indefinitely. That could indicate a non-periodic mechanical issue, which may defeat a correction algorithm that assumes true periodicity.
Patrick Wallace如此說
The drift over 10 minutes is 6.4 arcseconds, compared with the 22 arcsecond peak-to-peak swings of the periodic component. What is the size of the autoguiding box? And did you have Protrack enabled?
The largest effects in the data you posted are at the period of the RA worm (i.e. about 229.77 SI seconds). This means they are uncorrected periodic error, or more likely incorrectly signed PEC and hence twice as bad as without PEC. The main harmonics present are 1 cycle/rev, at about 6.6 arcsec amplitude, 2 cycles/rev, at about 1.5 arcsec, and 4 cycles/rev, at about 4.0 arcsec.
Again assuming your pixel-size calibration is correct, that suggests your MX is out of spec. However, I'd be interested to see what happens when PEC is enabled, based on the log file you posted.
我看不太懂
一切只好再測一次
想法找出為何極軸已對準
但導星放在加大兩倍的auto guider box(64x64 pixels)
卻常常會在十分鐘內跑出auto guider box問題
1800mm焦長極軸對準時照理應二十分都跑不出去才對
[
本帖最後由 wenjehpeng 於 2012-3-27 13:18 編輯 ]
