Volta

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Content rating
Everyone
50+
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Content rating
Everyone
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About this app

Volta shows you which deep sky objects are visible right now from your exact GPS position. Instantly check the altitude and direction of all 110 Messier and 109 Caldwell objects — no setup, no star charts, just open the app and look up.

FEATURES
- Complete Messier (M1–M110) and Caldwell (C1–C109) catalogs — 219 objects
- Real-time altitude and azimuth calculated from your GPS position
- Interactive sky map with pinch-to-zoom and tap to select objects
- Color DSS2 images from the CDS Aladin sky atlas for every object
- Sort by altitude, magnitude, or catalog number
- Filter by catalog (Messier/Caldwell), search by name, type, or constellation
- Adjustable minimum altitude threshold
- Object details: coordinates (RA/Dec), magnitude, angular size, constellation, type
- Direct Wikipedia links for every object
- 5 languages: English, Italiano, Español, Français, Deutsch
- Auto-detects your system language

PERFECT FOR
- Planning your observing session before heading out
- Quick reference at the telescope — which objects are highest right now?
- Learning the Messier and Caldwell catalogs
- Astronomy outreach and public stargazing events

Astronomical calculations based on Jean Meeus algorithms. Object positions are computed in real-time using your device GPS — no internet required for the visibility calculations.

Made by an amateur astronomer, for amateur astronomers.
Updated on
Apr 28, 2026

Data safety

Safety starts with understanding how developers collect and share your data. Data privacy and security practices may vary based on your use, region, and age. The developer provided this information and may update it over time.
This app may share these data types with third parties
Location and Device or other IDs
This app may collect these data types
Location and Device or other IDs
Data is encrypted in transit
Data can’t be deleted

What’s new

First release of Volta! Real-time visibility tracker for all 219 Messier and Caldwell deep sky objects. Features include interactive sky map, color DSS2 images, GPS-based calculations, and support for 5 languages.
Content rating
Everyone
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App support

About the developer
Michele Machetti
michele.machetti89@gmail.com
Italy