# Sidereal: Deep Sky Atlas — Deep-Sky Atlas & Night Planner

> Deep-Sky Atlas & Night Planner (iPhone/iPad app by Robert Corbin.)

- Source: https://appshunter.io/ios/app/sidereal-deep-sky-atlas/id6792598858 (this page in markdown: same URL + `.md`)
- Developer: [Robert Corbin](https://appshunter.io/developer/1890247992)
- Category: Education, Reference
- Price: $2.99
- Age rating: 4+
- Requires: iOS 17.0 · 30 MB
- Languages: American English
- Released: 2026-07-29
- Data updated: 2026-08-13
- User reviews in markdown: https://appshunter.io/ios/app/sidereal-deep-sky-atlas/id6792598858/reviews.md

## What is Sidereal?

Sidereal is a serious, offline sky atlas and observation planner built for amateur astronomers and astrophotographers — not another horoscope or AR toy. Every star position, rise time, and planetary coordinate is computed on your device from bundled professional catalogs, so it works perfectly at a dark site with no cell signal.

A REAL CATALOG IN YOUR POCKET
• 328,000 stars down to magnitude 10 (Hipparcos / ATHYG), with proper names, Bayer and Flamsteed designations, spectral types, distances and luminosities
• 13,000+ deep-sky objects — the complete NGC and IC catalogs
• The full Messier catalog and the Caldwell catalog, curated for observers
• Constellation stick figures, IAU boundaries and full constellation reference
• Everything is bundled and offline — no account, no cloud, no tracking

INTERACTIVE SKY CHART
• Pan and pinch a live planetarium view of the sky from your exact location and time
• Stars sized by magnitude and tinted by colour index; deep-sky objects drawn by type
• Constellation lines and labels, the ecliptic, an alt-azimuth grid and a true horizon with cardinal points
• Planets, the Sun and the Moon plotted from real ephemerides
• Tap anything to identify it and open a full data sheet
• Scrub time forward or back to see how the sky moves

PRECISE POSITIONAL ASTRONOMY
• Rise, transit and set times, plus an altitude curve for any object across the night
• Astronomical, nautical and civil twilight, and hours of true darkness
• Precession, nutation, sidereal time and apparent (of-date) coordinates
• Planetary and solar positions from the VSOP87 theory; lunar position, phase and illumination from an ELP-2000 series — all evaluated on device

PLAN YOUR NIGHT
• Tonight view: sunset to sunrise, moon phase and interference, planet visibility
• The best Messier and Caldwell targets tonight, ranked by altitude during darkness and distance from the Moon
• Observing lists you build yourself, and a session log for seeing, transparency, equipment and notes

TOOLS FOR THE FIELD
• Imaging field-of-view and image-scale calculator for any telescope and camera
• Visual field-of-view, magnification and exit-pupil calculator for eyepieces
• Polar-alignment helper with a live Polaris reticle clock position
• Local and Greenwich sidereal time, Julian date and obliquity

BUILT FOR THE DARK
• Red-light night mode preserves your dark adaptation
• Choose your site by GPS or enter coordinates for anywhere on Earth

Sidereal keeps your observing entirely private and entirely on your device. Own it — no login, no subscription round-trips, no light pollution of your data.


## Version history (last 2 releases)

### 2.0 — 2026-08-08

Version 2.0 adds Night Run Studio with equipment-aware target ranking, deterministic optimized observing sequences, saved field plans, completion tracking, warnings, atlas links, and system sharing

This release also refreshes the native iPhone and iPad experience, accessibility, privacy boundaries, and App Store screenshots. There are no accounts, subscriptions, advertising, tracking, or developer-operated services.

### 1.0 — 2026-07-29

No release notes.

## More apps by Robert Corbin

- [Daily Word Journey](https://appshunter.io/ios/app/daily-word-journey/id6761548266)
- [Hush Secret Text](https://appshunter.io/ios/app/hush-secret-text/id6761658175)
- [Renew Guard](https://appshunter.io/ios/app/renew-guard/id6761755447)
- [Receipt to PDF](https://appshunter.io/ios/app/receipt-to-pdf/id6761782025)
- [Route Your Pay](https://appshunter.io/ios/app/route-your-pay/id6761783719)
- [Tip Arbiter](https://appshunter.io/ios/app/tip-arbiter/id6761786879)

All apps by Robert Corbin: https://appshunter.io/developer/1890247992

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*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 2026-08-13.*