Find the nearest MPC station code
Choose a nearby MPC location for the alert ephemeris. The calculation runs entirely in your browser.
Location and limiting magnitude
Latitude and longitude are processed only on this device and are not sent to the server. The location button uses browser geolocation only after you grant permission.
The background map becomes progressively more detailed around MPC stations and is deliberately less detailed far away from them. This tiered coverage limits storage use on my web space. The nearest-station calculation still uses the coordinates; only the visible map detail varies.
The nearest station code will appear here after calculation.
The prepared registration mail may also include an experimental personal horizon profile as a plain-text attachment. Alternatively, one number from 0 through 90 after Horizon profile: sets a constant minimum altitude for every azimuth; none removes an existing profile.
Choose a position on the map
Click the map to fill in latitude and longitude above and compare the five nearest stations.
For the ephemeris only
The code is used by this alert service only to approximate horizon, twilight and topocentric position for your location.
For a regularly used site, the Minor Planet Center recommends obtaining your own observatory code. The official observatory-code guide explains the measurements, ADES submission and request form.
MPC code 247, “Roving Observer”, is intended only for a genuinely temporary or one-off site. Each observation then consists of two 80-column records: the first carries an uppercase V in column 15; the second carries a lowercase v, geographic longitude, latitude and altitude; both end in 247. Do not use tabs. Follow the current MPC roving-observer instructions.
The MPC says that the rover format is only for infrequently visited temporary sites. Before submitting, also review the general astrometry and submission rules.