Giordano Observatory · free tools
ISS transits across the Sun and Moon
I prossimi transiti della Stazione spaziale e di Tiangong davanti al Sole e alla Luna vicino a te: la striscia da cui si vedono, il punto dove andare, l'ora al secondo e come verrà la tua foto. Gratis.
Designed and developed byMattia Toto astrophotographer working with Giordano Astronomia · @toto.astrophoto
Tools for amateur astronomers are on their way
Free tools for anyone who observes and photographs the sky, designed by our observatory: we're testing them with a small group of amateur astronomers before opening them to everyone.
- TonightThe best targets from where you are for YOUR equipment, weather for stargazers with radar and lightning, how dark your sky is (SQM and LPI from David Lorenz's atlas), the Moon, Sun and planets, the ISS, meteors, comets and eclipses for your calendar
- EquipmentType what you own and the assistant fills everything in; see what fits on your sensor or in your eyepiece, on real photos of the sky; 21 calculators
- ChooseA 5-question quiz for the right telescope, camera or mount, with the reasons why; over 1,000 cameras compared and 69 programs with their official links
- LogThe objects you've seen and imaged, the 110-object Messier challenge and the plan for the night, also for N.I.N.A.
We'll let you know as soon as they're ready
How it works
Choose where you start from and how far you are willing to travel: the list shows the transits of the International Space Station and of the Chinese station Tiangong across the Sun and the Moon in the coming days. For each transit the map shows the strip of land, a few kilometres wide, it is visible from, and the spot on land to go to, with the nearest town and a button to open it in your navigation app.
Try the shot
Choose your telescope and camera, the frames per second and the exposure: you see the station cross the disc in your camera's frame, in slow motion or in real time, and all the frames in a single picture. We tell you how many frames it appears in, how big it is on the sensor and which exposure keeps it sharp.
How we calculate it
Orbits come from CelesTrak (NORAD data) and are computed with the SGP4 model; the Sun and Moon with J. Meeus's algorithms. Beyond 3 days times can shift by a few seconds: check again the day before. Only look at or photograph the Sun through a full-aperture solar filter.
Data: object catalogue from Stellarium (SIMBAD/VizieR, CDS Strasbourg); Digitized Sky Survey sky photos (STScI/NASA) via hips2fits (CDS); sky map by Giordano Astronomia with ESA's Hipparcos and Tycho-2 star catalogues; places: GeoNames (CC BY 4.0); sky darkness and LPI from David Lorenz's Light Pollution Atlas 2025 (djlorenz.github.io); ephemerides computed with J. Meeus's algorithms and JPL orbital elements. Camera data from the manufacturers' official spec sheets.
✦ Tools designed and developed by Mattia Toto for Giordano Astronomia · @toto.astrophoto