Radiant Drift offers a set of astronomical and geospatial web services, used to perform a variety of calculations related to objects in the Solar System and their positions with respect to Earth-based observers.

If you need to provide data related to the Sun, Moon, stars, meteor showers, eclipses, or more to your users, our APIs can help.

Building your own astronomical library or even learning to learn an existing one can be complicated task with a steep learning curve. If developer efficiency, focus and time to market are concerns, then using our well-tested web services can get you the data you need with ease.

In addition to many standard astronomical end points, we offer a variety of APIs providing data that can be difficult to find elsewhere. For example, we offer an 'az/alt search' API that can tell when the Sun or Moon will appear at particular position, or within an arbitrary position window. Our geospatial APIs include options to obtain a point-to-point sightline along a great circle with elevation included. And our eclipse APIs provide access to solar eclipse and lunar limb data which you typically won't find in other web services.

Please go ahead and sign up for a free account and try the service out! Our paid plans also include free trials so you can try out all the tools we have available.

Why Radiant Drift?

Radiant drift commonly refers to the change over time in the position of the apparent radiant point of a meteor shower. We think it's also a pretty snappy name for a collection of general astronomy web services!

About Us

We're the team who built The Photographer's Ephemeris, one of the world's best-known natural light planning tools for photographers. We've been working with software to calculate and visualize the sun, moon, and stars since 2008.

We use Radiant Drift web services in Photo Ephemeris Web and internally both web service and web app are built against our proprietary astronomical algorithm library, so you can rest assured that we have every reason in the world to keep things running smoothly.

Contact Us

You can reach us directly via the Help button at the bottom of this page, or you can write to us at support@radiantdrift.com.


Radiant Drift is a trademark of Crookneck Consulting LLC, doing business as Photo Ephemeris.

Software is Copyright © 2023 Crookneck Consulting LLC, except where noted.