Sidereal: Deep Sky Atlas
Deep-Sky Atlas & Night Planner
$2.99 · Designed for iPad. Not verified for macOS.
Plan your observing night, keep a searchable field notebook, and take your library with you using portable backups. All tools included.
Sidereal is an offline sky atlas and observing notebook for iPhone and iPad. Explore the sky, plan a night with your equipment, and keep your observing records together.
NEW IN 3.0
• Export and import your observing library: lists, night plans, equipment profiles and log entries.
• Recover recently removed personal records.
• Search lists, plans and observations, with summaries based on your saved log.
• Improved saved-data protection, proper observing-site time zones, corrected Pluto calculations and restored Caldwell identifiers.
EXPLORE OFFLINE
Browse 328,662 stars to magnitude 10.5 and 13,371 deep-sky catalog entries. The bundled collections include 109 distinct Messier entries and all 109 Caldwell entries. M102’s historical identity is disputed; NGC 5866 remains searchable by designation.
Pan and zoom the sky chart, inspect object details, and view constellation lines and boundaries, an altitude/azimuth grid, the ecliptic and solar-system objects. Change the observing time to explore the sky at your chosen site.
PLAN AND RECORD
Night Run Studio ranks candidates using your location, selected time and equipment assumptions. Save a field plan and mark completed stops. Keep observing lists and log notes for equipment, seeing and transparency.
FIELD TOOLS
Calculate imaging and visual fields of view, magnification and exit pupil. View sidereal time, Julian date and polar-alignment guidance. Switch to red night mode for observing.
UNDERSTAND THE LIMITS
Calculations are planning estimates. Rise/set times assume a standard horizon and atmosphere. Lunar positions are geocentric and omit observer parallax; Pluto’s fitted model is intended for 1800–2050. Scores do not measure weather or guarantee visibility. Models & Accuracy explains the methods.
YOUR RECORDS
No account, ads, subscription or in-app unlocks. Personal records stay on device unless you choose to export or share. Backups include lists, plans, equipment and log entries, but not site/display settings or recently removed records. Import validates files up to 25 MB and preserves conflicting records as separate copies.
Ratings & Reviews
- This app hasn’t received enough ratings or reviews to display an overview.
Protect and carry your observing library with JSON backup and import, recover recently removed records, and search lists, plans and log notes. Improved saved-data handling preserves older plans and reports storage failures. Corrected observing-site daylight saving, Pluto calculations and Caldwell identifiers. Refreshed navigation, clearer catalog credits and practical model-limit explanations.
The developer, Robert Corbin, indicated that the app’s privacy practices may include handling of data as described below. For more information, see the developer’s privacy policy .
Data Not Collected
The developer does not collect any data from this app.
Accessibility
The developer has not yet indicated which accessibility features this app supports. Learn More
Information
- Seller
- Robert Corbin
- Size
- 31.4 MB
- Category
- Education
- Compatibility
Requires iOS 17.0 or later.
- iPhone
Requires iOS 17.0 or later. - iPad
Requires iPadOS 17.0 or later. - Mac
Requires macOS 14.0 or later and a Mac with Apple M1 chip or later. - Apple Vision
Requires visionOS 1.0 or later.
- iPhone
- Languages
- English
- Age Rating
4+
- 4+
- Copyright
- © 2026 Robert Corbin
