親子觀星會

https://bbs.zwoastro.com/d/24803-am5-guiding-issue-random-ra-instabilities?fbclid=IwdGRjcAOMAZtjbGNrA4wBlGV4dG4DYWVtAjExAHNydGMGYXBwX2lkDDM1MDY4NTUzMTcyOAABHuS-whAUAqJd1L3Mva-9U9zQoEV_3Rq6_xu93rw1hErWdF92go9n0JzWeOcg_aem_-RBjnyeqyv5wrXp-UhQ13Q

其實這個事件已經在國外沸沸揚揚一段時間了(可能有半年了)，包含今年出貨的AM5n仍不定期AM5/AM5n有這種現象
其現象是RA會不預期的出現spike，輕者約4"，大多在4-8"，也有嚴重到7x"，日前九月ZWO宣稱找到問題後就沒下文了(宣稱只有少部分受影響)，美國ZWO技術支援團隊說是PCBA的問題，後來又說是RA電機供應商出問題，然ZWO仍持續要大家提供日誌分析(不是找到問題了嗎?)，原先還說是使用者風大，電纜線問題.，導星設定，不過看來越來越多案例了。
我的AM5n在星趴的前一天也有此現象，但我沒做很詳盡地排除分析，因為我第一次用雙砲，是否雙砲不平衡導致Dec也怪怪的，我後來將雙砲移到RST-135，AM5n改成單鏡子，外加土砲來回旋轉RA後就又沒發生這現象(CN有提到這個方式)。畢竟還有些變數因子在裡面，但這問題不是少數，對於AM3N/5N有興趣還未入手的人，可能先觀望吧! 以入手的，就看ZWO願不願意處理，我覺得有可能跟飛馬一樣放生吧! 畢竟出貨一年多，那麼多量，可能召回要賠不少。
我不能確定我一定是這個問題，
提供幾則在ZWO論壇的討論
https://bbs.zwoastro.com/d/24803-am5-guiding-issue-random-ra-instabilities
https://bbs.zwoastro.com/d/22171-problem-with-am5n
有興趣的還可以在CN更詳盡的分析說明
https://www.facebook.com/photo?fbid=34662556186668536&set=gm.25244591675170991&idorvanity=244730338917137

(https://scontent.ftpe8-1.fna.fbcdn.net/v/t39.30808-6/587764515_34662556223335199_3453931541205840774_n.jpg?_nc_cat=108&ccb=1-7&_nc_sid=aa7b47&_nc_ohc=8Ib9j9tjf-kQ7kNvwF36G5G&_nc_oc=Adm8dM-3_Ua5B2cp4l7xfT1bEHyBP6DkKRHws6zBvztcP7xArFQeMVukRj_R7bH6Vvo&_nc_zt=23&_nc_ht=scontent.ftpe8-1.fna&_nc_gid=z75kelPGGBvHY4IjmvC3Sw&oh=00_AfgaUY2ppmQI0rf0Ucq8YvocPyFoByQf4gBWpdwawNzk_Q&oe=6925CEA5)

https://bbs.zwoastro.com/d/22171-problem-with-am5n?fbclid=IwdGRjcAOMCahjbGNrA4wJpGV4dG4DYWVtAjExAHNydGMGYXBwX2lkDDM1MDY4NTUzMTcyOAABHiIJvJT5L9WTGCXIm6kaNFh1aORocK-aOcTm7c6ilwcuYnM7-14CzIKVtHV9_aem_FdKjPDkCMdAMvh6zFBq4qQ

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ai 回

AM5N 288sec refers to a common issue with the ZWO AM5 equatorial mount (AM5N), where the Right Ascension (RA) axis experiences a periodic error (PE) or guiding spike every 288 seconds, often causing massive sub-exposure losses in astrophotography, indicating potential mechanical issues like a tight belt or inconsistent gears within the mount.
What it means:
AM5N: The specific model of the ZWO AM5 portable mount.
288sec: The period (cycle time) of the mount's Right Ascension (RA) periodic error.
Why it happens:
This ~4.8-minute (288s) cycle points to a repeatable, mechanical flaw in the RA drive system, potentially due to belt tension, gear meshing, or manufacturing imperfections.
Common Solutions/Troubleshooting:
Check Belt Tension: Adjusting the belt tension (making it slightly looser) is a primary fix.
Gear Inspection: Some users have had factory replacements for gear issues.
PHD2 Guiding: Adjusting guiding aggressiveness (RA settings) can temporarily mitigate the symptoms, but doesn't fix the root cause.
In essence, when you see "AM5N 288sec," it's a sign of a known periodic error problem that astrophotographers often discuss online while trying to get clean, long-exposure images.

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