[詢問] Lodestar autoguider + Heq5pro + MaximDL 問題查詢

[funoooo]

這個星期我試了三晚 Autoguide 都失敗。不知錯在那裡？
我用 Maxim DL 找 Guide 星及 Calibration 時都沒有問題。但開始 tracking 後就 X-axis 開始數分鐘後就向下跌(Graphic mode) 跟著就出了 -0.5 位。但 Y-axis 完全沒有問題。我檢查過:
1. 所有螺絲鎖緊
2. Polar 對正
3. 做了 Balance
4. 沒有電線拖著

請問有沒有經驗人仕提出寶貴意見。

謝謝！

--------------------------------------------------------

另在 Maxim DL manual 發現此段文章:

The term ”stiction” comes from ”static friction.” Static friction occurs when two objects in contact are at rest or moving very slowly relative to each other. Dynamic friction occurs when the two objects are in motion. Static friction is always larger than dynamic friction, so when an object starts moving, the amount of friction present can change very rapidly. An example of this happens when you brake your car. Just before the car stops, you have to let up on the brake pedal; otherwise the car jolts to a stop (if you’ve been driving for years, you may not even be aware you are letting up on the brake).

Stiction occurs between the teeth in a gear system. Of particular interest here is the effect on worm drives, which are typically used in astronomical telescopes. When the drive is stationary, the gears ”stick together.” When the worm starts rotating, it pulls on the teeth of the worm wheel. In this situation, the wheel can bend, or the mounting or bearings can flex, at right angles to the normal rotation. The resulting motion is usually backwards – you try to move the mount North, and it goes South! This only happens for a brief period of time after reversing directions; eventually the worm turns enough that the gear is forced to move in the correct direction.

Stiction problems can be complex mechanically; it can often be hard to determine what the root cause is. Many telescope mounts – even high-end models – suffer from this problem, and it may vary between different samples of the same model. The problem has a terrible effect on guiding because it forces overcorrection.

If you experience bad guiding in declination and cannot resolve it through adjusting the calibration or aggressiveness, you may have a stiction problem. One solution that works is to note the average drift in declination, and disable corrections in that direction. The guider will only be able to push against the average drift, not with it. This works surprisingly well. Some users deliberately adjust their polar alignment slightly off to ensure that the drift is in a consistent direction. You should avoid large offsets that may cause field rotation.

http://www.cyanogen.com/help/maximdl/Ba ... iction.htm

-----------------------------------------------------------------------
會試下用 Anti-Stiction function, 希望能改善. 另再找時間拆開台 mount tune up 一下, 希望有改善.

[社長]

當A+B+C運作起來有問題時，要找出根源所在，最好還是用孤立法，例如你把已知能工作的LVI試導HEQ5 Pro，又或者把Lodestar去導已知沒問題的NEQ6 Pro，或許那樣可以找出一些問題。

我用自己的LVI或STi去導自己老舊的HEQ5 Pro，兩個組合都沒問題。

[funoooo]

Thanks, I will try different setting to see teh result.

[mwtse]

另在 Maxim DL manual 發現此段文章:

The term ”stiction” comes from ”static friction.” Static friction occurs when two objects in contact are at rest or moving very slowly relative to each other. Dynamic friction occurs when the two objects are in motion. Static friction is always larger than dynamic friction, so when an object starts moving, the amount of friction present can change very rapidly. An example of this happens when you brake your car. Just before the car stops, you have to let up on the brake pedal; otherwise the car jolts to a stop (if you’ve been driving for years, you may not even be aware you are letting up on the brake).

Stiction occurs between the teeth in a gear system. Of particular interest here is the effect on worm drives, which are typically used in astronomical telescopes. When the drive is stationary, the gears ”stick together.” When the worm starts rotating, it pulls on the teeth of the worm wheel. In this situation, the wheel can bend, or the mounting or bearings can flex, at right angles to the normal rotation. The resulting motion is usually backwards – you try to move the mount North, and it goes South! This only happens for a brief period of time after reversing directions; eventually the worm turns enough that the gear is forced to move in the correct direction.

Stiction problems can be complex mechanically; it can often be hard to determine what the root cause is. Many telescope mounts – even high-end models – suffer from this problem, and it may vary between different samples of the same model. The problem has a terrible effect on guiding because it forces overcorrection.

If you experience bad guiding in declination and cannot resolve it through adjusting the calibration or aggressiveness, you may have a stiction problem. One solution that works is to note the average drift in declination, and disable corrections in that direction. The guider will only be able to push against the average drift, not with it. This works surprisingly well. Some users deliberately adjust their polar alignment slightly off to ensure that the drift is in a consistent direction. You should avoid large offsets that may cause field rotation.

http://www.cyanogen.com/help/maximdl/Ba ... iction.htm

這一段很有啟發性，謝謝分享。

另外，先前見你提及的 HEQ5pro 極軸鏡LED太光問題解決了沒有？