Meade Image Processing Manual de usuario descargar pdf (Pagina 12)

Now you are ready to add images of the same color together. Effectively you will

produce a longer exposure image out of a few shorter exposure ones. You will observe how

the object emerges from the noise in the process.

At this stage you’ll have images in each of the three colors, red, green and blue (RGB).

It is advisable to apply some form of sharpening at this stage on each of the three color

components. The best software we have for this purpose is CCDSHARP, which uses the shape

of the blurred stars to restore the original sharp image: the pictured object will be blurred

the same way on the image as the stars are. One should be careful with sharpening though:

too much of it quickly increases noise and inserts nonexistent objects into the image.

CCDOPS can also compose the colors together at your command. To do this correctly,

however, you will need to specify the black and white points in all the color components.

To do this takes much experimentation, because incorrect cutoffs will upset the color

balance, leave too much (and colored) background haze, or remove too much of the object

at least in one color, or clip whole areas of the object. It goes by trial and error. Many of

them. But after many trials, you can come up with a very pretty picture indeed!

In real life Adobe Photoshop CS is more effective in doing color composition than

CCDOPS. It can compose colors without losing image depth. It can do nonlinear image

scaling (they call it curve), which is a very useful device to enhance the object’s contrast

without too much clipping. It can save images in formats that non-astronomers also

understand (e.g. TIFF) or formats suitable for the Web (JPG). The final touch in images is

always done in Photoshop. With a proper plug-in (called Liberator) installed, Photoshop

understands FITS images, and CCDOPS is able to save files in 16-bit FITS format.

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Meade Image Processing Manual de usuario Pagina 12