Image Processing: Tri-Color Imaging 1

Creating a Tri-Color Image

Open the three images taken with the B, V and R filters (that's blue, visual or green, and red). These images must be in the original ST-# file format. For ease of combining, the file name should end with the letter 'r' for the red filter image, the letter 'g' for the visua (green) filter image, and the letter 'b' for the blue filter image.

Select the "Mark Centroid" tool from the Astrometry Toolbar. The mouse cursor will now be a small set of crosshairs. Choose a compact, easily recognizable star near the central portion of the image, away from any nebulosity. This is the star that will be used to align all of the images. Next, select the chosen star in one of the images by carefully positioning the crosshairs over the center of the star and clicking once with the left mouse button. A small box will appear over the chosen star. Repeat this process for the other two images, being certain to select the same star in each image.