Skywatcher polar alignment RA angle

[Guest]

I'm pretty comfortable with doing the polar alignment on my HEQ5 using the handset but I have one small question. You have to rotate the RA such that the 0 of the polarscope reticule is at the top. That's fine and I can do that but what's the significance of the odd angle that the RA is in at that position? Wouldn't it have been better if the 0 position of the reticule corresponded to the home position (weights down)? Or perhaps even better if it corresponded with the counterweight bar being horizontal and then I could use a spirit level to get the right position instead of judging by eye.

I think I'm right in saying that they could have chosen any position except that the algorithm in the handset would have to be adjusted accordingly.

Cheers

Steve

 

[MarkAR]

On my AZ EQ6 I rotate both Axis 90º to get the polar scope right way up. Does seem daft.

[Tomatobro]

Its the axis your are trying to align so it does not matter where the weights bar end up.  Polaris rotates around the true North position

[Guest]

I understand that but if it doesn't matter where the weights bar ends up why not arrange it such that the weights bar is in some recognizable position such as horizontal or vertical instead of some weird intermediate position? At the moment I have to judge by eye when the 0/6 line on the reticule is vertical. This is not so easy when you are crouching on the ground and squinting throughtthe polarscope.  I'm trying to find a way to make it a bit more repeatable.

 

Edited April 20, 2020 by Guest

[Jiggy 67]

I think that they just didn’t bother when fitting them, there’s nothing significant with it. It’s not the case with the EQ6 R Pro which comes with the polar scope calibrated 

Edited April 20, 2020 by Jiggy 67

[Guest]

Thanks. Presumably different heq5s will have different orientations.  I realise it doesn't matter but it just seems a bit sloppy. 

[jambouk]

You can rotate the reticule yourself inside the polar scope to get it where you want. I think it would be very time consuming for the manufacturer to align 0 at the top with the weights down as this would have to be undertaken after assembley of everything (namely the polar scope screwed into its mounting), and then it would need recentering... It may seem sloppy, but I suspect it wouldn't be perfectly accurate, time consuming, and it isn't necessary. But some people do rotate it themselves which is relatively easy to do; the centring again afterwards is what takes the time. 

On the whole when I used a polar scope, I never bothered rotating the RA to get 0 at the top; if Polaris needed to be at 100 degrees, I would position Polaris on the circle in the polar scope just after the 3 o clock position, irrespective of where zero was. I suspect this degree of accuracy in polar alignment on an HEQ5 is unliekly to be the limiting factor when it comes to unguided (or maybe even guided) images.

James