How to Stack Tracked Star Shots With a Foreground

One of the fundamental issues in astrophotography is the general lack of light. To combat this, many serious astrophotographers turn toward equatorial mounts to allow them to get more light, but this can create difficulties if you have a foreground subject as well. This helpful tutorial will show you how to composite a foreground shot with a tracked night sky shot. 

Coming to you from Milky Way Mike, this great video tutorial will show you how to composite a foreground scene with a tracked night sky shot. Because the night sky gives off so little night, in addition to using wide aperture lenses, many serious astrophotographers turn to equatorial mounts. These are special motorized camera mounts that synchronize to the rotation of the Earth to counteract star trails caused during long exposures. The problem then is that by rotating the camera to follow the night sky, the foreground then rotates relative to the plane of the camera, thereby blurring it. Photographers solve this by taking a separate exposure, but compositing the two can be a bit tricky since the camera moves during the sky exposure. Check out the video above for the full rundown of the technique. 

Alex Cooke's picture

Alex Cooke is a Cleveland-based portrait, events, and landscape photographer. He holds an M.S. in Applied Mathematics and a doctorate in Music Composition. He is also an avid equestrian.

Log in or register to post comments
4 Comments

Pls. Fix Title! Should be: "How to use Photoshop to replace the Sky with the Milkiway"

Ended up not getting too far... This is a video about compositing shots from two different lenses and locations, not how to track and stack WITH the foreground you have when you shot the Milky Way. This is Photo Art, not Photography.

Really nice image, but it doesn't tackle the real issue when you have complicated foreground and it gets way blurry when you stack the images. For example this one. This is a stack out of 24 images (unedited)

Excellent information, thank you for sharing and saving me hours of experimenting! I'm just wondering, how do you shoot tracked long-exposures for stacking? If the tracker is always moving, isn't the composition going to slightly change between exposures? Maybe it's not enough to notice. Thanks!