Transit Visibility & Ephemerides

Select a planet from the local CSV (same dataset as the Exoplanets page), set your observing site(s), then generate upcoming transits and check visibility.

Planet name

RA (deg) Dec (deg) Epoch T0 (BJD_TDB) Period (days) Duration (hours)

Observing Site(s)

Latitude (deg) Longitude (deg, East +) Elevation (m) Min altitude (deg)

Require night (Sun alt ≤ −12° at some point)

Add a second site (optional)

Lat2 (deg) Lon2 (deg, East +) Elev2 (m) Min alt 2 (deg)

Ephemerides

From (UTC) To (UTC) Max events

Transit Altitude / Airmass / Parallactic Angle (selected row)

Click a row in the table to plot; shaded region shows ±1 transit duration.

Notes & Sources

Planet parameters loaded from /assets/data/pscomppars_recent.csv (NASA Exoplanet Archive).
GMST and sidereal-time transform: simple polynomial adequate for planning.
Solar position: low-order approximation of ecliptic longitude/equation of time; good to a few arcminutes.
Airmass: Kasten & Young (1989) optical airmass formula; clamp at low altitude to avoid divergence.
Parallactic angle: standard spherical-trigonometry expression using hour angle, site latitude, target declination.
Time systems: epochs usually BJD_TDB in archive; here we display UTC; for high precision, confirm with observatory tools.