Re: Drift graph
Posted: Sat Oct 09, 2021 10:24 am
EW is East West, or RA. The image can have a steady unwanted movement, or drift, along this direction for several reasons, mostly to do with mount mechanics or periodic error.
NS is North South, or Dec. The image drifts along this direction generally because of polar alignment error.
There is a good explanation of this here http://www.minorplanet.info/ObsGuides/M ... gnment.htm
EW and NS are not up and down along the edges of the camera view. Instead the angle varies with where the scope is pointing, and the camera rotation. The image needs to be platesolved (or at least matched carefully with a star map), to determine which way is NS and which is EW. This is what the grid lines in the solved image tell you.
NS is North South, or Dec. The image drifts along this direction generally because of polar alignment error.
There is a good explanation of this here http://www.minorplanet.info/ObsGuides/M ... gnment.htm
EW and NS are not up and down along the edges of the camera view. Instead the angle varies with where the scope is pointing, and the camera rotation. The image needs to be platesolved (or at least matched carefully with a star map), to determine which way is NS and which is EW. This is what the grid lines in the solved image tell you.