Photographing the pass
The motion that makes Apophis special is also the entire photographic problem: at roughly a Moon-width per minute, the asteroid trails across any exposure longer than a few seconds. Decide up front which photo you want:
- The trail (recommended). Fixed tripod, wide-to-normal lens, dark sky. Long or stacked exposures turn the asteroid into a thin streak moving against the star field — the one image that tells the story of the night. Starting point: 20–30 s frames, f/2.8 or faster, ISO 1600–3200, shot continuously and stacked later; the asteroid draws its own line through the sequence.
- The point. Freezing a magnitude-3 point needs exposures of a few seconds at most, which demands fast glass and high ISO, and buys you a picture indistinguishable from a star. Only worth it as a labelled before/after pair showing the position change between frames a minute apart.
- The timelapse. The same continuous frames as the trail, rendered as video — the motion plays back in seconds and reads instantly to non-astronomers. If you shoot for the trail, you get this free.
The boring essentials
- Dark site first — the camera fights skyglow exactly as your eyes do. The location table is the photographic decision too.
- Manual focus on a bright star before the window; autofocus will hunt and lose.
- Know the track from a finder chart in advance and frame wide — hunting a faint mover through a viewfinder wastes the night.
- A phone propped against a rock shooting its night mode will record the star field but very likely not the asteroid; treat any phone capture as a bonus, not the plan.
- Settings above are honest starting points, not gospel — bracket early and check histograms while the asteroid is still rising.