SKILLS FOR STARGAZERS

How to guide your gear with PHD2: Guiding can make or break your long exposures. Here's how to master it

- Jim Owen

Guiding is essential for deep-sky astrophotography, because even the most precise setups can introduce small tracking errors that affect your images. These are caused by a mix of mechanical flaws, imperfect polar alignment and atmospheric effects, all of which can cause stars to drift during long exposures, resulting in elongation or blur.

By using guiding accessories and specialist guiding software, such as the free PHD2, you can continuously monitor a reference 'guide' star and send corrective commands to your mount. This will keep your stars pinpoint-sharp, allowing much longer exposures. Longer exposures mean dramatically improving sharpness and depth, revealing faint details in nebulae, galaxies and star clusters.