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Old 02-06-2020, 11:31 AM
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billdan (Bill)
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Join Date: Mar 2012
Location: Narangba, SE QLD
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Originally Posted by Camelopardalis View Post
Maybe I’m being overly dense here, but how does one get the scope orthogonal to the grid?
Those of us who have a Roll Off Roof, it will be difficult as you can't use the scope while its horizontal because the walls are too high.

If you did have line of site of a fence, you would use a spirit level to ensure the telescope is horizontal and measure from the ground the height of the optical axis.
Then place the grid onto the fence with its centre at the same height off the ground as the OTA optical axis.
Assuming level ground of course it gets more complicated with sloping ground.
I guess you could use a collimating laser to line up the OTA with the grid.

Instead of a grid you could use a Dart Board with concentric circles, those circles will become elliptical if there was tilt in the camera.
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