Ioptron polar alignment and zero position

[Wiu-Wiu]

Maybe a silly question, but I have been wondering about this... Especially since my mount only finds zero position in RA (DEC keeps slewing so I need to stop it and set it manually) 

 

Ioptron polar scopes are not always inserted perfect level to the 'zero' position (scope perfectly straight on top). Some are rotated - that's why the polar scope has a bubble level attached to it. 

When you polar align, you need to rotate the axis so the polar scope bubble level is horizontal - that way you can place polaris at the exact spot on the "watch". 

 

My question: is the preferred zero position the position where the bubble level is leveled (thus the spot in which you polar align the mount? Or is the zero position still the spot where the scope is sitting on top (and the bubble level may be rotated) (The auto zero position in RA is where the scope is on top)

Does it even matter? 

[Davey-T]

I don't think the mount has any idea where zero position is until you tell it by setting the bubble level then loosening the clutches and rotating to zero.

The bubble level should put  6 oclock at the right position, I put an O ring behind mine to give a small bit of adjustment.

Curious to why it doesn't stop, do you mean it keeps going without stopping or just stops at the " wrong " place ?

Dave

[Wiu-Wiu]

The RA swings to one side, then returns, but once the counterweight starts "rising" again, it quickly returns and finds equilibrium. 

DEC goes to one side (usually East first), then returns and keeps going to the other side until the clutch slips if I don't stop it. I usually let it balance in RA and then manually slew DEC to align that little screw on the DEC saddle with what looks like the middle of the mount. 

 

 

For the record: I usually polar align with the polar scope level (6 at 6 o'clock) - then rotate both axis to the starting ('zero') position - then start star alignment. But usually first alignment is off quite a bit. Which is curious, singe the mount has GPS.

[Davey-T]

That all sounds very strange, all I do is scroll to zero position on the handset, press and it wanders off in RA / Dec to where it thinks zero is and stops, only goes in one direction, no returning, I then use the hand control to get the spirit level level  and loosen the clutches and rotate manually to zero position, weights down, scope up north and that's it then star align.

First star alignment is off in mine as well but usually just on the edge of the FOV of a 26mm eyepiece with 110 f/7 refractor.

Dave