Sky Tonight
A quiet readout of what is actually overhead. The tool takes your latitude, longitude and the current moment, then asks Swiss Ephemeris for each planet — apparent altitude, azimuth, visual magnitude, elongation from the Sun, lunar phase, and the night-by-night rise, culmination and set times. No mythology, no forecast. Just the geometry of the visible sky as it stands now.
How the numbers are computed
Each planet is run through swe_calc_ut at the current Julian Day, then transformed from ecliptic to horizontal coordinates using your geographic position and local sidereal time. Magnitude follows standard photometric models. Rise, set and culmination are solved by iterating altitude across the next twenty-four hours until the horizon crossing is found within a fraction of a minute.
State, not omen
A planet rising in your east is not a message. It is a fact. The point of this page is to return your eyes to the actual sky — the one above your roof, not a chart on a screen. Knowing that Jupiter is fifteen degrees up in the south at twenty-two thirty changes how you stand at the window. Symbol and observation belong to the same gesture.
How to use it
Open the page after sunset. Read the table top to bottom: which bodies are above the horizon, how bright, how high. Step outside if any of them are. Bring binoculars if Mercury or Mars is faint. The tool also marks elongation and lunar phase, so you know whether the Moon will wash out a dim object or leave it visible. Plan a walk around it, not a ritual.
Where it sits in the wider system
Sky Tonight is the observational sibling of the natal chart and transit pages. The same Swiss Ephemeris call powers all three; only the projection differs. Pair it with Eclipse Visibility for upcoming dimmings, with Planetary Hours for diurnal rhythm, and with the Moon Calendar for the slower lunar arc. Together they form a quiet civic almanac of the sky above you.
Frequently Asked Questions
Do I need to enter coordinates manually?
You enter a city; geocoding through OpenMeteo returns latitude, longitude and timezone. The numbers update from there. If you travel, change the city — horizon coordinates depend on where you actually stand, not on where your account was created.
What does apparent magnitude mean here?
It is brightness as seen from Earth. Lower numbers are brighter; Venus reaches near minus four, while a faint Uranus sits around plus six, just at the edge of unaided sight. Atmospheric extinction near the horizon is not modelled, so very low objects look brighter on the page than to your eye.
Why does my phone app show a slightly different time?
Different tools choose different horizon definitions — geometric, refracted, upper-limb, centre-of-disc. The differences run a minute or two. Sky Tonight uses geometric horizon with standard refraction, the convention used by most ephemerides. Treat any rise time as accurate to the nearest minute.
Is light pollution accounted for?
No. The page reports astronomical brightness, not what your specific street allows. Under a city sky, magnitude four is roughly the practical limit; under a dark rural sky you reach six. Compare the listed magnitudes to your local conditions and decide whether a body is reachable by eye.