Which instruments can I use in the app?

A nocturnal (by Johann Michael Hager, after 1707), a horizontal sundial (Christoph Schissler, 1569), a mechanical celestial globe (Georg Roll & Johannes Reinhold, 1586), and an astrolabe (Johannes Praetorius, 1568).

How quickly will the instruments be unlocked?

The sundial will become usable once you’ve completed the first path for the nocturnal, the celestial globe after the third path for the sundial, and the astrolabe after the fourth path of the sundial.

Can I try out different features of the instruments on my own?

Yes, in the Exploration Mode you can explore the nocturnal and the sundial freely and use them on the sky. To unlock this mode, work your way through the paths of the nocturnal or the sundial until a small E appears in the upper-right corner of the path-selection screen. Click on the E to start the Exploration Mode for this instrument.

Can I also use BEHIND THE STARS with a group?

Yes. In the Workshop Mode you can create your own digital room, which other users can then join by entering a code. In fact, anyone who’s downloaded BEHIND THE STARS and to whom you’ve given the code can join. To create such a room, you need to play through the first path for both the nocturnal and the sundial. Note that the Workshop Mode requires an internet connection.

Is there more to do in the Workshop Mode?

Yes. Here you’ll not only find the four instruments which you’ve already encountered, but also two programs to observe your surroundings. For instance, you can observe the Moon over the course of a month and create a Moon Journal or find the direction of true south using the Sun’s shadows over the course of a day. Note: If you wish to create a Moon Journal just by yourself, you’ll have to set up your own “group” and use the code you’ll be given to enter your own digital room.

Are there tutorials on how to use BEHIND THE STARS?

Yes. https://www.bts-lab.deyou’ll find explanations of how the app – and especially the Workshop Mode – functions.

Why can’t I go backwards arbitrarily?

That’s due to how BEHIND THE STARS is programmed. Perhaps you’ve already noticed that many parts of the app are calculated live for your latitude, the current sky at your location, or your local time. These live elements appear not only as 3D-objects, but also as 2D-lines or highlights. It’s not possible simply to “rewind” all these elements simultaneously. Instead, BEHIND THE STARS uses a system of checkpoints, which allows you to jump back to a selection of the most important points.

Can I find such original instruments near me?

Yes, many science or technology museums as well as decorative arts museums have historical scientific instruments. One place to find out more is: www.scientific-instrument-commission.org.

Where can I make a suggestion?

Please write to BehindTheStars@skd.museum. We look forward to your feedback!