Umbra for OnStep

Umbra is a hand controller for telescope mounts running OnStep or OnStepX, designed for use in the dark. Every pixel is deep red on black, one slider dims both the backlight and the interface, and the system keyboard and bright dialogs never appear, so your night vision stays intact.

CONTROL
• Large RA / Dec pad that makes it obvious which axis you are driving, with a centre stop
• Slew rates from 1× up to the mount's maximum, on screen or with the volume keys
• Tracking on/off and sidereal, lunar or solar rates
• Live RA / Dec (or Alt / Az) readout and mount status
• The interface reads the mount's current state when it connects

TONIGHT
• 200 of the best telescope sights: the Moon, the planets, all 110 Messier objects and showpiece clusters, nebulae, galaxies and double stars
• Grouped by distance from the zenith, or from where the telescope is pointing right now
• Drawn icons, magnitude, size (in degrees or Moon diameters) and a short observing note
• One tap to GoTo

MOUNT
• Guided multi-star alignment with suggested stars spread across the sky
• Polar alignment error from the mount's own pointing model, with a bullseye diagram
• Park, unpark, set park position, home
• German equatorial mounts: pier side, time to meridian, automatic flip, preferred pier side
• Fork, German equatorial and alt-azimuth mounts are detected automatically

SETTINGS
• Send the phone's time and your typed-in site to the mount (no location permission)
• Fine tracking-rate trim, reverse axes, mount address and port

PRIVATE BY DESIGN
No accounts, no ads, no analytics. Umbra never contacts the internet: it only talks to your telescope on your local network.

REQUIREMENTS
A telescope mount running OnStep or OnStepX with Wi-Fi (built-in, the OnStep Wi-Fi add-on or the Smart Web Server). Join the mount's Wi-Fi in Android settings; some phones connect more reliably with mobile data turned off.

Umbra is an independent app by Physics Anonymous LLC and is not affiliated with the OnStep project. Deep-sky data: OpenNGC by Mattia Verga (CC BY-SA 4.0).