![]() But thanks to the power of neural networks, StarNet and StarXTerminator make star removal as easy as clicking a button. And while PixInsight, the dedicated astroimage-processing program, has built-in capabilities to create a star mask, the more general-purpose Photoshop does not. It’s easy to overlook objects or introduce unwanted artifacts. ![]() While masks do this rather well, making them takes time and requires some level of expertise to get them right. Likewise, applying a virtual mask to an image protects specific elements (e.g., stars) so that adjustments such as noise reduction and sharpening don’t adversely affect them. This is like a housepainter using tape to shield areas from a new color. Because many stars are already bright, stretching the dimmer parts of an image can damage the stars in the same way as overexposing them, and care should be taken to avoid this.īecause stars can’t be stretched far - and also because they don’t require the same amount of attention and processing as the faint, delicate features of a nebula - one approach to dealing with them is to mask them out. ![]() The pixel values must be nonlinearly stretched (brightened) to reveal what’s hiding in its initial linear state. This typically yields a dark-looking image with little contrast. When a raw image file is imported to your computer, it is in a linear state, meaning that the brightness values from pixel to pixel are the same as when they were recorded by the camera. The same issue rears its head when processing an image. You may find that a good compromise is taking shorter exposures, but more of them. While faint deep-sky objects benefit from long exposures, brighter stars can quickly saturate a sensor, resulting in colorless and unnatural-looking orbs. The problemįor an astroimager, stars present unique challenges. Or, the stars can be left out for a dramatic display of isolated nebulosity - an especially popular look with narrowband images. When processing is complete, the stars can easily be placed back into the image if the imager desires. The freeware StarNet can be used within PixInsight or as a standalone tool StarXTerminator can be used as a plug-in with PixInsight and Photoshop, but requires users to purchase a license.Īfter using them, the target objects in your image can be manipulated without concern for those pesky stars. The programs StarNet and StarXTerminator were developed independently, but both use a form of artificial intelligence (AI): neural networks trained to recognize stars and remove them from astroimages. Two new, cutting-edge tools make it much easier. Image-processing programs like PixInsight by Pleiades Astrophoto and Adobe Photoshop have offered methods to remove stars from images - but they can be labor intensive and yield mixed results. But for nebulae and other objects, the presence of these bright points of light in an image can hinder an astroimager from teasing out details. Of course, there are exceptions with targets like open clusters. One of the ironies of deep-sky imaging is that stars are generally not the stars of the show. Stars have been completely omitted from this narrowband image of the Statue of Liberty Nebula (NGC 3576) to feature its nebulosity.
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