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Originally Posted by Stevec35
Thanks for your comments Ivo. I rarely use Star spikes pro - I think I pressed "buy" too quickly on my computer screen <g>. Your rework is interesting but I'm wondering now whether fake spikes are really worth the trouble.
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Yeah, it's a tough one. Personally, I do really appreciate diffraction spikes from my humble Newt as they give an extra visual cue as to the brightness, color and just general prominence/depth of a star. It's like a form of instant (but coarse) photometry. They're also helpful in discerning the properties of close together stars that would otherwise bleed into one in a single elongated star in a refractor.
Plus I grew up with the Hubble images being the absolute holy grail of astronomical imaging.
Most poorly executed fake ones do the opposite for me - they confuse - as they give me false cues; one has a prominent spike, but the other, nearly as bright, doesn't because the imager 'forgot' to put them on.
They are really distracting when they're not exactly as blurry as the rest of your real world image, because your eyes are drawn to their sharpness. You can't help but interpret that as a (false) depth cue - sort of a false depth of field effect with the sharp star being in the foreground ("more in focus").
Quote:
Originally Posted by Stevec35
So what tool do you use?
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<spruik>I use my own processing suite (
www.startools.org).</spruik>It's got a module called 'Synth' that allows you build a virtual telescope to the desired specs. Then it uses those specs to calculate how the light would refract around the different components in your scope and applies that to every star in the image (after it has performed some basic photometry to detect all stars, their magnitude and their color).
This procedure can be abused to obtain absolutely perfect real looking diffraction spikes, but its main purpose was really to 'augment' the stars in an image so they would look tighter, brighter and more '3D'. The technique is incredibly effective on star clusters.