Sidereal Time App

Sidereal helps astronomers, telescope users, and night-sky observers track Local Sidereal Time quickly and reliably.

Use Sidereal to view the current local sidereal time, calculate sidereal time manually from longitude, search locations, and plan ahead with future sidereal time tools. You can also create scheduled alerts so you never miss an important observing window.

Features:

View current Local Sidereal Time

Calculate sidereal time manually from longitude

Search by city or location

Use decimal or DMS longitude entry

Schedule sidereal alerts and reminders

Export upcoming alerts to your calendar

Browse future sidereal times for planning

Choose light, dark, or night-vision display modes

Sidereal is designed to be fast, practical, and easy to use in the field, whether you are setting up for imaging, aligning a mount, or planning an observing session.