Difficulty & pace
Easy–Moderate. Multiple 0.5–2 mile round-trip walks on boardwalks and paved paths, plus short dirt approaches to riverside bends; total elevation per session ~50–200 ft. Nights run 3–4 hours with breaks. Elevation 6,200–7,800 ft—expect a gentler pace uphill.
Weather & safety
Nights can be 40–50°F with breeze; bring layers, gloves, and a light shell.
Geothermal hazards: we remain on signed trails/boardwalks; no off-boardwalk night travel. Steam drifts with wind—protect gear from condensate; wipe lenses often.
Wildlife: bison, elk, bear are active; we maintain legal distances, carry bear spray, and avoid river meadows in the dark if animals are present.
Air quality/steam: if wind shifts or steam overwhelms a composition, we pivot to alternate angles or higher, drier overlooks.
Vehicles & roads
Primary sites are paved-access; some lots close at night—our plan respects posted hours/closures. No rough-road travel.
Logistics
Base area: Gardiner or West Yellowstone (both give efficient loops to Mammoth/Firehole corridors).
Meet times: ~6:00 pm (evening field) and ~12:30 am (astro block), adjusted to cloud cover and wildlife activity.
Services & comms: Good services in gateway towns; spotty reception in-park—download offline maps and carry paper backups.
Permits & rules: We follow NPS regulations; participants are responsible for any additional permits required for commercial crews. No drones.