2028 NZ eclipse — Claude Code handoff: Clyde photographic site survey

← Total Solar Eclipse — 22 July 2028

Objective: find the best practical camera/viewing position around Clyde Dam and Hawksburn Road for the total solar eclipse of 22 July 2028. Optimise not merely for an unobstructed Sun, but for a potentially exceptional photograph with the low eclipsed Sun visually aligned down Lake Dunstan / Cromwell Gorge, mountains framing it, and the lunar shadow visible across the landscape.

Known eclipse geometry

• Around Clyde/Alexandra, maximum is approximately 16:16 NZST (04:16 UT), with ~2m53s totality.
• At maximum the Sun is roughly 9–10° above the NW horizon, azimuth approximately 311–312° (verify precisely for each candidate coordinate).
• Use the Besselian-element model and coefficients documented in the parent note for precise centreline/site calculations. Do not rely on straight interpolation of the two-minute published path table.
• Exact centreline is secondary to weather, access and photographic geometry: sacrificing a few seconds of totality is acceptable for a substantially better site.

Primary area and candidate positions

• Clyde Dam Upper Lookout / Sunderland Street area: easiest drive-to candidate, roughly 200 m elevation. Dramatic view into Lake Dunstan/Cromwell Gorge. Critical question is whether the ~312° skyline clears a ~9.5° Sun.
• Clyde Dam Lookout / Hawksburn Road side: higher and potentially better aligned. Geological field-trip material confirms vehicle access to a lookout; road becomes rougher/higher beyond.
• Hawksburn Road / Cairnmuir side: search progressively higher legal, car-accessible positions. DOC material says the road is steep/rutted/rocky and 4WD may be required in winter; do not assume public vehicular access beyond documented points.
• Cairnmuir Flats (~627 m) is an upper-area lead, not automatically the optimum: the desired point is probably the LOWEST accessible elevation that gives excellent lake/gorge alignment while putting the skyline safely below or attractively around the corona.

Useful observed evidence

A geotagged Clyde Dam photograph has been found at approximately -45.180186, 169.309692, elevation ~197 m, camera heading 315.38°. That is only ~3–4° clockwise from the expected eclipse azimuth, so it is valuable ground truth for the relevant landscape direction. Verify the source/metadata independently before using it quantitatively. Cromwell itself is more NNW (~331°), so the eclipse is not exactly along the reservoir centreline from every dam position; camera position must be optimised for perspective alignment.

Topographic / DEM task

Use authoritative LINZ Topo50/topographic data and preferably a numerical DEM. A convenient terrain source used successfully in related work is AWS Terrarium elevation tiles: https://s3.amazonaws.com/elevation-tiles-prod/terrarium/{z}/{x}/{y}.png ; decode elevation metres as R*256 + G + B/256 - 32768. LINZ elevation data may be preferable if straightforward to obtain.

1. Establish accurate coordinates/elevations for the accessible Clyde Dam Upper Lookout, Clyde Dam/Hawksburn lookout, road parking/turnouts and any legal higher candidate points.
2. For each candidate, calculate the solar azimuth/elevation through C2–maximum–C3, not just one instant.
3. Sample the DEM along azimuths approximately 305–320° (fine angular resolution), out to at least 50 km. Include Earth curvature/refraction if material at these distances.
4. Convert terrain elevations into apparent vertical angles from the camera position and construct a skyline profile.
5. Overlay the solar path/corona position on the skyline. Determine clearance of the solar centre and solar limb at C2, maximum and C3.
6. Separately calculate bearings to the visible reservoir/gorge centreline/features so that photographic alignment can be optimised, rather than merely checking a 312° ray.
7. Search candidate positions along accessible roads for a sweet spot where the eclipse lies visually down/over the reservoir and gorge, preferably with ridge skyline a few degrees below or framing the corona.
8. Assess whether a modest move uphill or sideways improves alignment. Return exact lat/lon and elevation for the best few positions, with Google Maps links.
9. Produce a map plus horizon-profile plot for the finalists. If possible, create a synthetic view or annotated real photograph showing where the eclipsed Sun would appear.

Optimisation criteria

Weather context

Central Otago is attractive because it is very dry, but winter valley fog/inversions are a genuine risk. Lauder/Manuherikia Valley remains an important weather/backup area: atmospheric research there benefits from clear skies, dry atmosphere and low horizons. An elevated Clyde/Hawksburn site could combine better photographic geometry with some protection against valley fog.

Deliverable

Do the numerical site survey rather than just describing how it could be done. Return a ranked shortlist (ideally 3–5 precise coordinates) with: access description, elevation, centreline offset/totality duration, solar azimuth/elevation, maximum skyline angle near the Sun, angular clearance, reservoir/gorge alignment, photographic merits, risks, and map link. Highlight one recommended photographic position and one robust weather/access fallback. Preserve scripts/data/plots so the calculation can be rerun as better DEM/access information becomes available.

Sources already identified

• EclipseWise path table
• NASA GSFC Besselian elements
• LINZ Topo50
• Interactive Clyde Topo50
• DOC Cairnmuir Hill access information