# Comet Book > Comet viewing guide with 3D solar system visualization. (iPhone/iPad app by Vixen Co.,Ltd..) - Source: https://appshunter.io/ios/app/comet-book/id604782335 (this page in markdown: same URL + `.md`) - Developer: [Vixen Co.,Ltd.](https://appshunter.io/developer/536188843) - Category: Education - Price: Free - Rating: 5.00/5 from 2 App Store ratings · 51 written reviews indexed - Age rating: 9+ - Requires: iOS 12.0 · 10 MB - Languages: English, German, Japanese - Released: 2013-03-07 - Data updated: 2026-08-10 - Monetization: free - User reviews in markdown: https://appshunter.io/ios/app/comet-book/id604782335/reviews.md ## What is Comet Book? The Comet Book app clearly shows when Comets can be viewed and in which direction. The direction and elevation of a Comet can change noticeably in a day due to its fast apparent motion. The moon and a bright planet may be convenient as a guide to find the comet though they have large apparent motion, too. This app determines where Comet is in the sky when it becomes visible at your observing site. You can easily start your observation of a Comet by using Comet Book as a guide to the direction and elevation of the comet. In addition, the new “3D Solar System seen from Space” mode allows you to view the motion of Comets and planets turning around the sun. Please take a look the comet’s movement around our solar system. ## Key features - Comet viewing direction and elevation - Real-time celestial object tracking - 3D Solar System mode - Visualize comet and planet motion - Observing site guidance ## Recent user reviews (10 of 51) All indexed reviews: https://appshunter.io/ios/app/comet-book/id604782335/reviews.md ### 5/5 — It’s a joy *2025-11-23, version 2.7.4* Nice and simple interaction design allowing the user to understand from different perspectives. ### 3/5 — MPCデータのダウンロード *2025-09-22, version 2.7.2* 対応中らしいけどMPCデータのダウンロードが行われず、直近の彗星が表記されません。 また自動でダウンロードされるのは便利ではあるが、手動ダウンロード出来るようにしてほしいですね ### 1/5 — MPCファイルが更新できない、されない *2025-09-22, version 2.7.2* 2.7.2に上げましたが、更新されないままです。2025と彗星検索しても何も表示されません。 再インストールしましたが、MPCファイルが---の状態です。 iPhone 14proでos26です。 よろしくお願いします。 ### 3/5 — MPCデータが更新反映されません。 *2025-09-21, version 2.7.2* C/2025 R2 (SWAN)がアップデートしても反映されません。 ### 4/5 — MPCのアップデートが *2025-09-20, version 2.7.2* 全体的には日時による彗星の位置把握に役に立つアプリです。UIもシンプルで難しくもありません。左下ボタンからの立体的に位置情報を知ることができる表示は想像力を掻き立てられます。 1点課題としては、MPCの更新タイミングにムラがあり、最新の彗星情報が他の人には届いたのに自分のにはなかなか届かなかったりします。現状、自分では任意に更新が出来ないので、MPCボタンを押したらデータが最新かチェックされてDLされるとか、下に画面引っ張ったら最新かチェックされてDLできるような機能があると嬉しいです。 ### 1/5 — 問題が解決していない *2025-09-19, version 2.7.1* iOSで使おうとアプリをダウンロードしましたが、彗星リストが保存されません。 ### 1/5 — 彗星データ更新されない *2025-09-18, version 2.7.1* 2025lemon の軌道などを知りたくてインストールしましたが、検索出来ず、mpcデータも更新が~~で変化しません。 知人のは出てきたので機種の問題なのでしょうか。iPhone3rdSEでも見れるように改善希望します。10月の観測までに使えることを願います ### 3/5 — ピンチアウトの文字 *2025-09-15, version 2.7.1* ピンチアウト時に惑星名の表記文字が拡大されず メガネをかけないと見えない 元々の惑星名の書体も コントラストを配慮して見やすい文字で表記して欲しいです。 ### 5/5 — Best comet viewing app! *2025-07-15, version 2.7.1* This one of the very few comet finder apps and it even provides a 3d orbit view. It's difficult to find in the English app store, maybe due to a few Japanese symbols still used in the app? ### 3/5 — アップデートできません *2025-04-18, version 2.7.1* バージョン2.7がインストール済みだと最新の2.7.1がインストールできません。 2.7ではC/2025 F2 SWANが彗星登録画面に表示されないので、27.1にしたいのですが。 ## Frequently asked questions about Comet Book ### How accurate is Comet Book for finding comets? Comet Book provides direction and elevation data to help you locate comets. The app's accuracy is dependent on your device's sensors and your ability to interpret the provided celestial coordinates. ### Does Comet Book work offline? The description does not specify offline functionality. However, for real-time tracking and viewing directions, an internet connection is likely required. ### What devices support Comet Book? Comet Book is available for iPhone, iPad, and iPod devices, as indicated by the supported devices list. ### What is the age rating for Comet Book? Comet Book has an age rating of 9+, making it suitable for younger users interested in space exploration. ### How often is Comet Book updated? The latest version, 2.7.4, was last updated on November 18, 2025. This indicates a relatively active development cycle for the app. ### Does Comet Book have ads? No, Comet Book does not contain advertisements. The app is free to download and use without any ad interruptions. ### Can I track planets with Comet Book? Yes, the 3D Solar System mode allows you to view the motion of planets turning around the sun, in addition to comets. ### What makes Comet Book stand out from other astronomy apps? Comet Book focuses specifically on providing clear guidance for comet observation with direction and elevation data, alongside a unique 3D visualization of the solar system's movements. ## Version history (last 5 releases) ### 2.7.5 — 2026-04-22 Some bugs have been corrected. ### 2.7.4 — 2025-11-18 We have updated the app to support comet orbital-element eccentricities up to 10.0. ### 2.7.2 — 2025-09-20 Some bugs have been corrected. ### 2.7.1 — 2024-08-31 Addressed an issue where the comet list was not being saved. ### 2.7 — 2024-08-07 The COMET BOOK app now allows you to download comet orbital elements from the Minor Planet Center and select any comet to display. ## Apps similar to Comet Book | App | Rating | Price | Category | | --- | --- | --- | --- | | [Comet Tracker App](https://appshunter.io/ios/app/comet-tracker-app/id6737527992) | — | Free | Education | | [MeteorActive](https://appshunter.io/ios/app/meteoractive/id1205712190) | 4.8 (1,968) | Free | Education | | [SkyORB Classic Astronomy](https://appshunter.io/ios/app/skyorb-classic-astronomy/id338051358) | 4.5 (23) | Free | Education | | [SpaceStationAR LITE](https://appshunter.io/ios/app/spacestationar-lite/id1023377153) | 4.5 (139) | Free | Education | | [NEOScope](https://appshunter.io/ios/app/neoscope/id6477293859) | 5.0 (1) | $0.99 | Education | | [Bright Comets](https://appshunter.io/ios/app/bright-comets/id1523594527) | 4.3 (150) | Free | Education | ## More apps by Vixen Co.,Ltd. - [Moon Book](https://appshunter.io/ios/app/moon-book/id906552724) - [PF-L Assist](https://appshunter.io/ios/app/pf-l-assist/id940306488) - [Solar Book](https://appshunter.io/ios/app/solar-book/id1078873201) - [NightVision Light](https://appshunter.io/ios/app/nightvision-light/id1081761997) - [Mars Book](https://appshunter.io/ios/app/mars-book/id1342509724) All apps by Vixen Co.,Ltd.: https://appshunter.io/developer/536188843 ## Related topics [comet tracker](https://appshunter.io/ios/topics/comet-tracker) · [comet tracker app](https://appshunter.io/ios/topics/comet-tracker-app) · [bright comets](https://appshunter.io/ios/topics/bright-comets) · [comet track](https://appshunter.io/ios/topics/comet-track) · [cometads](https://appshunter.io/ios/topics/cometads) · [fireballs in the sky](https://appshunter.io/ios/topics/fireballs-in-the-sky) --- *Data collected daily from the US App Store and indexed by [AppsHunter](https://appshunter.io/). User reviews are verbatim App Store reviews. Ratings, prices and chart positions refresh continuously; this snapshot is from 2026-08-10.*