One of the best improvements in Adobe Photoshop CS5
is High Dynamic Range (HDR) processing. In its pure form, HDR allows users to merge three exposures — one each for shadow, midtone, and highlight detail — into one image with clear detail, from deep shadows to bright highlights. Toning with HDR allows you to adjust this now-single image to bring out more detail. It’s important to use an astroimage that has been stretched properly — that is, it has full detail at all levels of illumination without any clipping (see my November and December 2010 “Imaging the Cosmos” columns).Astronomy magazine subscribers can read the full column for free. Just make sure you're registered with the website.