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About andrea1984

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  1. I want to give a contribution to the calculation, this is the calculation that I use to know how many seconds of exposure can be set on the camera before the trail is noticeable, based on the calculations made by the site (http://www.sceneplanner.com/tool3.php): Tha calculation does not take care of: - seeing - resolution of the optics (optical resolution = 116 / focal lenght) Example when the orientation is portrait: Input parameters: HorSize = Horizontal Sensor size (mm) HorPx = Horizontal resolution of the sensor (pixel) FL = Focal length of the optics (mm) Dec = Declination (degree) TrailPx = Maximum number of pixel we accept before before assuming the photo has the trail Calculated parameters: FOVHor = Field of view orizontal (rad) Res = Resolution (rad / pixel) AngSpeed = Angular speed (rad / s) Seconds = number of seconds that a pixel takes to move of TrailPx pixels FOVHor = 2 * atan( HorSize / (2* FL)) Res = FOVHor / HorPx AngSpeed = (2 * Pi) / 24 * abs(cos(Dec * Pi / 180)) -> Seconds = Res * TrailPx / AngSpeed * 3600 To calculate the maximum exposure for the top or bottom frame add or subtract FOVHor / 2 when calculating the AngSpeed: AngSpeed = 2 * Pi / 24 * abs(cos((Dec + FOVHor / 2)* Pi / 180)) For landscape orientation use the vertical resolution and size. Setting the TrailPx to 12.5 pixel this calculation gives the same results as the site previously published
  2. I'm not even able to remove the wheel from the rod, even after removing the screw. Attaching the photo. Thanks
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