# Sky Time > Astronomy time data: Julian, Universal, and Sidereal times with location sensing. (iPhone/iPad app by John Kennedy.) - Source: https://appshunter.io/ios/app/sky-time/id473539346 (this page in markdown: same URL + `.md`) - Developer: [John Kennedy](https://appshunter.io/developer/284943103) - Category: Reference, Education - Price: Free - Rating: 4.20/5 from 17 App Store ratings · 30 written reviews indexed - Age rating: 4+ - Requires: iOS 10.0 · 1 MB - Languages: American English - Released: 2011-10-25 - Data updated: 2026-06-09 - Monetization: free - User reviews in markdown: https://appshunter.io/ios/app/sky-time/id473539346/reviews.md ## What is Sky Time? Sky Time is a simple app that displays Astronomy related times, including Julian Date and Universal Time. It also makes use of your device's ability to sense location to determine the Sidereal Time. Sky Time is a useful tool to have to hand when setting up your telescope! * Displays local, Julian, Local Sidereal and Universal Time. * Night-vision friendly red display. * Pop-up descriptions of the times at your fingertips. ## Key features - Displays local, Julian, Local Sidereal, and Universal Time - Calculates Sidereal Time using device location - Night-vision friendly red display - Pop-up descriptions for time data ## Recent user reviews (10 of 30) All indexed reviews: https://appshunter.io/ios/app/sky-time/id473539346/reviews.md ### 3/5 — I loved this but it doesn’t work any more on new gear *2025-06-17, version 1.4* The app can’t determine current location under iPad OS 18.5 ### 5/5 — Awesome app *2024-01-20, version 1.4* Awesome app. About the only thing they can do better is add in watch complication options for each unit of time. I’m personally dying to find a watch complication for MJD from anyone. Really! Great work. Love your app. Hope to love it better. ### 2/5 — Does not work if you’re in half hour time zone *2023-02-17* Review title says it all. I’m in a half hour time zone so the app miscalculated UTC as it doesn’t account for this. ### 4/5 — Nice, but... *2020-08-12, version 1.4* I like almost everything about this app except for one little thing that just bugs me. The sidereal time is displayed down to the second, but is only accurate to the minute. For some reason the developer chose to display the same value for seconds on sidereal time as for local and universal time. That’s just not right. ### 3/5 — Not available as Complication *2020-05-04, version 1.4* Would be nice. No? ### 4/5 — Nice app, but problem with sidereal time. *2019-11-18, version 1.4* I use this in a lab course on radio astronomy I teach to quickly see what the local sidereal time is. This is the problem: When the seconds roll over from 60 to 0, the minutes do not increment by 1 until after 20 seconds have passed by. This is on an iPhone 11 pro. ### 4/5 — Name *2019-11-12, version 1.4* Where did you get the name sky time ### 3/5 — Text to small in field *2019-06-30, version 1.4* Exactly the app I was looking for: something to be a field clock while doing astronomy. Except that everything but the local civil time is too small to easily read at night, and so I don’t use it. ### 5/5 — Great clock. Great astronomy app (with suggestion to developer) *2019-01-20, version 1.4* If you are an observer this one is for you. Don’t need to say anything else. Case closed. As I said one suggestion to developer... Can you make option to display sidereal time as the primary clock? That would be awesome. Right now it’s just as one of the secondaries. That clock I think is the main reason why someone would get this app, so make this a primary clock, please. Or include as an option, please. Thank you very much. ### 3/5 — Parts not working *2018-06-24, version 1.4* I think the actual information displayed is correct, but... - It won't display in landscape mode on an iPad, so I can't leave it propped up on a table and read it properly. - The help menus don't work--I can't get the explanations of the different times that are shown in the examples in the AppStore. ## Frequently asked questions about Sky Time ### What kind of time data does this app provide? The app displays local time, Julian Date, Local Sidereal Time, and Universal Time. It uses your device's location to accurately calculate the Sidereal Time, which is crucial for astronomical observations. ### Who would find this app useful? This app is particularly useful for amateur astronomers and anyone who uses a telescope. It provides essential time data needed for setting up equipment and tracking celestial objects. ### Is this app free to use? Yes, the app is completely free to use. There are no in-app purchases or advertisements, ensuring an uninterrupted experience for users. ### What are the key features of this app? Key features include the display of various astronomical time formats, location-based Sidereal Time calculation, a night-vision friendly red display mode, and helpful pop-up descriptions for each time value. ## Version history (last 5 releases) ### 1.4 — 2016-12-19 This app has been updated by Apple to display the Apple Watch app icon. Fixed a bug related to displaying the Modified Julian Date ### 1.3 — 2016-10-25 Added a simple Watch app, so your Julian Date and LST is always with you. ### 1.2 — 2016-10-19 Updated for newer devices. ### 1.1 — 2011-12-03 Fixed a bug displaying Universal Time Improved time display ### 1.0 — 2011-10-24 No release notes. ## Apps similar to Sky Time | App | Rating | Price | Category | | --- | --- | --- | --- | | [SunGraph](https://appshunter.io/ios/app/sungraph/id321534034) | 3.1 (12) | Free | Reference | | [Astrophotography Planner](https://appshunter.io/ios/app/astrophotography-planner/id1661476234) | 5.0 (4) | $4.99 | Reference | ## More apps by John Kennedy - [Pocket Universe](https://appshunter.io/ios/app/pocket-universe/id306916838) - [What's Up?](https://appshunter.io/ios/app/whats-up/id393023070) - [Spelling Test](https://appshunter.io/ios/app/spelling-test/id478561217) - [Asstrology - Your Future Is Behind You](https://appshunter.io/ios/app/asstrology-your-future-is-behind-you/id486930635) - [Pocket Universe Classic](https://appshunter.io/ios/app/pocket-universe-classic/id567184849) All apps by John Kennedy: https://appshunter.io/developer/284943103 ## Related topics [heartopia time](https://appshunter.io/ios/topics/heartopia-time) --- *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 2026-06-09.*