Guide and Imaging Camera Alignment

[martinclayden]

I use a Star Adventurer (SA) tracking mount and I'm trying to understand if my guide camera needs to be exactly aligned to the RA axis of the SA for the PA routine in SharpCap to work correctly.

If "yes" then how do I ensure this alignment to ultimately achieve sub-minute PA of the SA.

If "no" then how does SharpCap ensure correct PA of the SA - given the imaging axis is misaligned to the RA axis.

I suspect my question demonstrates confusion and lack of understanding! , but, that's why I'm here, and I would appreciate any help from the experts on this forum please

Thanks

Martin

[admin]

Hi Martin,

the answer is no – you don't need to perfectly align your guide scope/camera with the RA axis to get the polar alignment to work properly.

How can this be? SharpCap looks for the point in the image that the stars appear to rotate around to find the place where the RA axis is currently pointing. It's basically the same as the fact that Polaris stays in the same point in the sky even though you're not standing at the North Pole – the only point that can appear to stay still is the point that the rotation is happening around.

Once SharpCap has the RA axis position calculated and the position of the north celestial pole calculated by plate solving, it's easy to guide the user to make the movements needed to put the two in the same spot.

Cheers, Robin

[martinclayden]

Thanks Robin,

That's clear !

Regards

Martin