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Step 2 — Target

The target step asks: what are you observing?

The target picker has three modes — pick the one that matches what you know about your target.

Three picker modes

A curated list of commonly observed objects, grouped by category. The React port pulls these from the CommonTarget table; categories include:

  • Planets — major solar-system bodies.
  • Galaxies — well-known galaxies (Andromeda, the Pinwheel, …).
  • Nebulae — bright emission and planetary nebulae.
  • Clusters — open and globular clusters.
  • Asteroids and Comets — moving objects worth observing routinely.
  • Variable stars — sources useful for variable-star photometry curricula.

Pick a featured target and the editor populates the appropriate position kind automatically — fixed for stationary objects, ephemeral for moving objects.

Free-form catalog search. Type an object name, designation, or identifier; the API resolves it across multiple catalog sources in priority order:

  1. Locally maintained NORAD satellite database — for satellite designations (e.g. ISS, Starlink IDs).
  2. Locally maintained MPC orbits — minor planets / asteroids by designation or name.
  3. Locally maintained MPC comets — comets.
  4. Locally maintained solar system objects — planets, moons, and other well-known bodies.
  5. SIMBAD — for anything not found locally (stars, galaxies, deep-sky objects, named astronomical targets).

The search returns enough metadata to populate the appropriate position record automatically — fixed for stationary objects, catalog or ephemeral for moving / time-varying ones — so you don't have to type coordinates.

Custom coordinates

Manual entry. Specify a position in one of the supported coordinate frames:

  • Equatorial (RA/Dec) — the most common.
  • Galactic (l/b).
  • Ecliptic (λ/β).
  • Horizontal (alt/az) — only useful when the observation is bound to a specific telescope and time.

Custom coordinates always create a FixedPosition. Use this mode when you know the coordinates and don't need the system to resolve a name.

Position kinds under the hood

The picker mode you choose dictates what kind of TargetPosition record gets attached to the observation:

Picker mode Position kind Notes
Featured (fixed source) FixedPosition Coordinates in the chosen frame
Featured (moving body) EphemeralPosition Ephemeris drives time-varying coords
Featured (small body with orbital elements) OrbitalPosition Kepler elements
Search (resolved by catalog) CatalogPosition Pinned to a catalog entry; or EphemeralPosition / OrbitalPosition for moving bodies returned by the search
Custom coordinates FixedPosition As entered

What a target carries

Beyond a position, a Target record carries:

  • Name — required (the final-step checklist verifies it).
  • Description — optional free text.
  • Brightness model — used downstream when a data request asks for an SNR-based exposure (the brightness model is what lets the scheduler turn "target SNR = 50" into a concrete exposure time).
  • Saturation model — caps maximum exposure to avoid saturating the source.
  • Temporal and spectral components — for variable sources whose brightness changes with time and/or wavelength.

Brightness modeling matters most when you're doing SNR-based optical imaging — see Step 3 — Requests for the exposure mode menu.

Component reference

← Step 1 — Accounts · Step 3 — Requests →