Construct RGB from Channel Files Action Detail

Handy tip: This action works great with the newest FITS Liberator software from NASA / ESO for opening standard format FITS files.

Synthesize Green Channel Action Example

Handy tip: Sometimes even with RGB starfield shots this action can help bring out the true color in stars and help eliminate "greenish" stars.

Color Gradient Removal Action Example

Handy tip: Color Gradient Removal can even normalize a consistent off-gray color of light pollution, such as the orange glow you might see from sodium-vapor city lights.

Light Pollution Removal Action Example

Chances are good that, unless you're using the Hubble Space Telescope, you need to subtract a background atmospheric light level from your photos to bring out the best results. Simply setting the black point will not give you a proper color balance in your deep sky objects and stars. This action makes a "false flat" image, then subtracts that level of light pollution from the entire image, producing a more contrasty image with truer colors.

Restrictions in the light path, different responses to light arriving at the imager at different angles... All of these can create vignetting, gradients and/or hot spots in your images. The trick is to determine the proper illumination levels to subtract across the image. The Light Pollution Removal action does that, and you can even remove noise from the background of some types of images while you're at it!

Handy tip: Even if you take the trouble to shoot true flat images and include them in your processing, the Light Pollution Removal action can still help to further refine your results, giving you deeper contrast and a more 3D feel.

Select Brighter Stars Action Example

Select Brighter Stars finds the stars in your image, even those intermingled with a deep sky object, and selects them. Further Photoshop operations can then be done on just the selected area. You can also invert, expand, shrink, and feather the selection using Photohop's Select menu.

Handy tip: Ever get dark halos around your stars from sharpening or combination of Hydrogen Alpha and color data, and wish there was an easy way to reduce or remove those halos without negatively affecting anything else? Select the stars with this action, expand the selection by a few pixels using Select-Modify-Expand to surround the halos, and use Filter-Noise-Median then Edit-Fade-Lighten. Problem solved!

Make Stars Smaller Action Example

Handy tip: This action actually affects the entire image, and can help smooth the image as well as reducing the star size, but it can be limited just to the stars by running the Select Brighter Stars action first, then running Make Stars Smaller, then running ...Per Selection Only.

Less Crunchy More Fuzzy Action Example

The Less Crunchy More Fuzzy action not only smoothes out star edges, but also helps clean up dark, crunchy-looking noise in your deep sky objects, giving the image a less processed, more natural appearance.

Handy tip: Run the Select Brighter Stars action, then Select-Modify-Expand the selection by 2 pixels, run the Less Crunchy More Fuzzy action, then finally the ...Per Selection Only action. This allows you to be more aggressive in sharpening your deep sky objects then bring the stars back to looking natural.

Horizontal and Vertical Banding Reduction Actions Example

Up to now one has either had to try to hand-edit this out, or just not stretch the luminance levels so far as to make the banding appear out of the background, losing precious dim detail. With the innovative Horizontal and Vertical Banding Reduction actions in this set this noise is history in a matter of seconds, allowing you to bring out the faintest details in your images.

Handy tip: If your image has strong horizontal banding, and you run Horizontal Banding Reduction, you may see remnant vertical banding that was hidden before. You can then run Vertical Banding Reduction and end up with a pattern-free image!

Increase Star Color Action Example

The Increase Star Color action is perfect for fixing this. There is very likely some color information around the edges of those hot white stars, and this action pulls that color back into the star centers for an overall more visually pleasing appearance.

Space Noise Reduction Action Example

Handy tip: Sometimes you want to remove noise from only the very darkest parts of the image, to preserve the most detail in dim nebula or galaxy images. Deep Space Noise Reduction provides an even less aggressive noise reduction that really makes your image look cleaner.

Color Blotch Reduction Action Example

Color Blotch Reduction, which also appears in my dSLR Tools set for daytime photography, finds the most visible color noise in open areas and eliminates it, while avoiding damage to the detail in the objects in the image.

Handy tip: If you have both color and luminance noise, chances are removal of the color noise will make it less necessary to do aggressive luminance noise reduction. Run Color Blotch Reduction first, and then judge the level of luminance noise to remove. You may have to do less than you think.

Reduce Blue/Violet Halos Actions Example

Reduce Small Blue/Violet Halos and Reduce Small Blue/Violet Halos actions will find these halos and darken them, giving you truer star color and better sharpness.

Local Contrast Enhancement Action Example

Local Contrast Enhancement, which also appears in my dSLR Tools set for daytime photography, is a more sophisticated form of local contrast enhancement than you may have read about on the photo retouching sites, because it emphasizes darkening more than lightening.

Handy tip: Use Local Contrast Enhancement to eliminate a "foggy" look.

Lighten Only DSO and Dimmer Stars Action Example

Handy tip: If an image needs a LOT of brightening, often a combination of this action and the Curves function will give the most natural looking result, while still keeping bright star sizes small.

Enhance DSO and Reduce Stars Action Example

Handy tip: When you think you're done with an image, try running this action on it. Chances are it will make an overall visual improvement.

B&W -> Ha False Color Action Example

This isn't an attempt to make a black and white image into a full-color shot, but simply the creation of an alternate visualization of what the object looks like in the color of light it was actually imaged. While others are presenting their Ha images in plain old black and white, make yours stand out!

If you'd like to see actions for other filter colors, please let me know and I'll consider creating visualization actions for additional colors in a future version of this actions set.

B&W -> OIII False Color Action Example

Star Diffraction Spikes Action Example

If your telescope doesn't make diffraction spikes and you want them in your images - or you'd like to enhance the ones you get optically - I've included four different actions for making them. You have the option of adding them to your images in the quantity you want, from spikes on even the smallest stars to spikes on only the biggest, brightest ones.

Handy tip: If the results of running Star Diffraction Spikes are too gaudy for your tastes, run ...As Layer On Top, then set the mixing percentage to less than 100%. This reduces the brightness of just the spikes - you can make them as subtle as you like!

Handy tip: If you get unnaturally strong or wide spikes on huge stars, run ...As Layer On Top, then do Filter-Other Minimum. You can make the spikes smaller / thinner - choose a radius value that creates the look you want.

Astro Frame Action Example

Handy tip: Set the background color to whatever you like in the Photoshop Elements tools palette before running the action and the frame will be made that color when the action is run.

...As Layer On Top Action Example

...As Layer Underneath Action Example

...Per Selection Only Action Example

This is a bit complicated, so let me put forth an example to help a bit... Let's say you use the Select Brighter Stars action to select just the stars, then run Make Stars Smaller. The Make Stars Smaller action operates not only on the stars but on everything between the stars. To restrict the results to only the stars themselves - i.e., the selection you had made before running Make Stars Smaller - use the "...Per Selection Only" action. You will find the results restricted just to the selection, which is remade afterward as well.

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Date this page was last updated: January 14, 2008
Some of the images on this page courtesy Bud Guinn and Dr. Greg Parker.

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Contact the author at NCarboni@att.net

Copyright © 1995-2008 ProDigital Software, Noel Carboni