Volta

Real-time Messier & Caldwell deep sky object visibility from your location.

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.