Using the form seen in the screenshot above, the user can change the scale and orientation of the reference stars from the star catalogue to match the stars in the CCD frame. The stars from the catalogue are drawn as an overlay of red circles, each with a small cross in the center.
Arrows: Move the reference stars up, down, left or right by one pixel. When holding down the [Ctrl] key simultaneously, the stars will be shifted by ten pixels. By pressing both the [Shift] and [Ctrl] keys, the stepsize will be further increased to 30 pixels.
Magnitude: The limiting magnitude for reference stars shown. Choose this value so that the stars from the catalogue correspond to the stars seen in the images, or increase the limiting magnitude to avoid crowding.
Focal Length: Set the focal length so that the scale of the overlay of reference stars matches the stars in the image. If the focal length required for the match differs significantly from the value specified in the program settings, you may want to update the settings accordingly.
Position Angle: Set the position angle so that the orientation of the overlay of reference stars matches the stars in the image. If the position angle required for the match differs significally from the value specified in the program settings, you may want to update the settings accoringly.
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