Best place to focus within fov?

[swag72]

I spent ages last night trying to get my focus right - I've yet to see if it has worked. Anyway, I digress!

What I did find last night was that if I focused in the middle of the fov, when I moved the star to the upper left of the fov it had lost focus. Yet if I focused at the upper left, the focus was fine in the middle.

So, is there an optimum part within the fov to get your focus right? I've always just done it in the middle before.

[Catanonia]

I have been told to focus 2/3rds away from the centre of the FOV for best results on fast scopes.

[martin_h]

I always focus "off centre"

[ollypenrice]

Sara, I strongly suspect this is your orthogonality problem in a new guise.

I have never taken much notice of where my star is - though on the TEC, which doesn't have a flat field, I keep it near the middle. On the FSQ I focus anywhere. What's the thinking behind off axis, anyone? A compromise across the range?

What about focussing near the part of the image which draws the eye or has the most need for resolution?

Olly

[swag72]

Cheers folks - And thanks Olly, just what I wanted to hear .... Not!!

I am at the end of my tether with this damn orthogonality issue. I am looking at ordering a new flange in the New year, and hope that may sort it, as it will not sit flat against either the OTA or Moonlite. We will see!