Nebula Book is an app designed to assist in capturing images of celestial bodies such as nebulae, star clusters, and galaxies. Developed by 株式会社 ビクセン, this app was created in response to the needs of users who were unsure about the positions of celestial objects and the appropriate focal lengths for capturing them. With a wide range of celestial bodies that can be photographed using standard camera lenses or medium telephoto lenses ranging from 50mm to 300mm, Nebula Book provides a curated list of relatively easy-to-capture celestial bodies from the vast astronomical information embedded in the Vixen's star navigation system, STARBOOK-TEN.

Nebula Book is a valuable app for beginners in astrophotography. By using the sensors on your smartphone or other devices, it informs you about the position of the selected celestial body in the night sky. By aligning the orientation of your camera with the orientation of your device, you can easily capture photos of your desired celestial objects. For capturing nebulae and star clusters, it is recommended to use Vixen's Polarie, AP Series, SX Series, or other equatorial mounts for tracking shots.

Please note that the scroll switch button, which displays a star chart indicating the direction you are pointing your smartphone towards, is located in the bottom right corner of the screen. However, this feature may not work on some devices that do not have an electronic compass.