Meade Autostar Software Manual page 26

Autostar IP
When the command is complete, the number of colors that were found and the number of colors used in
the resulting image are displayed. You should modify the number of Quantum Levels (in the RGB Merge
dialog box) so that the two values are fairly close together. Generally, finding 300 to 400 colors results in
the best image. Using a large number of colors results in an image that has a very small change in colors,
using fewer colors increases the color differences seen in the image
The resulting color image has its own unique palette, subsequent image processing, such as scaling,
generally gives poor results. You should first scale the individual red, green, or blue grayscale images,
then combine them using the RGB Merge command.
To preserve the color palette, the color image must be saved in the BMP format.
Frequently, many composite RGB images are not perfectly registered, the telescope may have moved
between the exposures. This results in one or more of the images being offset from the other images.
The Offsets {XE Image:Offsets} the X (horizontal) direction or the Y (vertical) direction one pixel at a time
for each of the Red, Green, and Blue image files.
After the image is first merged, you should examine some prominent part of the image using the
Magnifier. If color fringes are noticed over the entire image, one or more of the separate images needs
to be aligned with the others. Count the number of pixels that the images appear to be offset, then set the
value in the appropriate red, green or blue X or Y offset fields. When the images are re-merged, the new
offset values will be used.
If the images were taken from a telescope that was not properly Polar aligned, the resulting images may
also show some rotation from one image to the next, The RGB alignment may help reduce the effect
slightly, but cannot correct for the rotation.
The individual offsets may also be automatically determined by using the RGB Alignment function from
the Image Utilities dialog box. To automatically align the images, first locate an area in the image that
contains a well defined single object, such as a star. Then draw a box around the object by depressing
the left mouse button and dragging the box to the desired size. When the button is released, the Image
Utilities dialog box will be displayed. If all three RGB buffers contain valid images, the RGB Alignment
item will be enabled. Upon selecting the auto alignment function, the X and Y offsets for each image will
be determined and will automatically merge the buffers to produce a new image.
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