This web page is a guide for Principal Investigators (PIs), Contact Scientists (CSs), and NGOs supporting programs at Gemini with non-sidereal targets. Here you’ll find notes, tips, and advice that should help you to maximize the odds of success for your non-sidereal programs.

Useful Tools, Tips, and Websites

The JPL Horizons Ephemeris Service

Horizons is the ephemeris service offered by the Solar System Dynamics group at NASA’s Jet Propulsion Laboratory, and is used by the OT to fetch ephemerides for non-sidereal targets in Gemini programs. Horizons is capable of much more, however, and there are a number of parameters that may come in useful when designing observations and building observing programs at phase II. At several points this page will refer to numbered observer quantities that can be selected as outputs by Horizons (see screenshot below); on the Horizons webform they are listed when you click the link to change Table Settings. Note that descriptions of each output parameter printed from Horizons, along with the units used, are listed in the footer of an ephemeris when it is calculated.

IAU Minor Planet Center (MPC) Observatory Codes

568 is the Maunakea MPC observatory code.
I11 is the Cerro Pachón MPC observatory code.

You can use these to designate Observer Location in Horizons instead of typing out Observer Location names in full. Useful if you’re in a hurry.

NASA Small Body Database

The Small Body Database is another service offered by NASA JPL that provides access to data related to asteroids, comets, centaurs, Trans-Neptunian Objects (TNOs), and interstellar objects. Contact scientists and NGOs may be most interested in orbital elements, orbit diagrams, and alternate designations.