Comet Book is an Android app developed by 株式会社 ビクセン that provides a comprehensive guide to observing comets. This free app is categorized under Education & Reference and offers a wealth of information and features for astronomy enthusiasts.

With Comet Book, users can easily determine when and where a comet can be viewed in the sky. The app takes into account the fast apparent motion of comets, which can change noticeably in just a day. It also suggests using the moon or a bright planet as a guide to locate the comet, despite their own large apparent motion.

One of the standout features of Comet Book is its "3D Solar System seen from Space" mode. This mode allows users to visualize the motion of comets and planets as they orbit the sun. It offers a fascinating perspective on the movement of comets within our solar system.

Whether you're a beginner or an experienced astronomer, Comet Book is a valuable tool for observing comets. Its user-friendly interface and comprehensive information make it easy to start your observation of a comet by using the app as a guide to its direction and elevation in the sky.

Please note that while Comet Book provides a wealth of information, it does not offer any contact information for the developer or encourage users to provide feedback or suggestions.