Nebula Book is an app developed by Vixen Co. Ltd. that aims to assist users in capturing images of celestial objects such as nebulae, star clusters, and galaxies. It was created in response to the common challenge faced by astrophotography enthusiasts - not knowing the precise location of celestial bodies or the optimal focal length for capturing them.

With Nebula Book, users can easily identify celestial objects that can be photographed using standard camera lenses ranging from 50mm to 300mm. The app draws from the extensive database of celestial information embedded in Vixen's STARBOOK-TEN celestial navigation system to compile a list of objects that are relatively easy to photograph.

This app is particularly useful for beginners in astrophotography as it provides essential information on the positioning of selected celestial objects in the night sky. By aligning the camera's direction with that of the device (e.g., iPhone) and fixing them in place, users can greatly enhance their chances of capturing the desired celestial images.

For capturing nebulae and star clusters, it is recommended to use equatorial mounts such as the Vixen Polarie, AP Series, or SX Series for tracking photography.