From York Tam post on Facebook: 1. get peak tower info: 淩霄閣 peak tower co-ordinate from google maps: 22.2712357,114.1499638 height: 428 m (389m ?) https://en.wikipedia.org/wiki/Peak_Tower 2. get approximate photo location distance: distance from google map: 8300 km approx azimuth is calculated to be ~ 2.94 deg above horizon (top of 2 tower) 3. use mooncalc date and time: 6 Sep 2022 00:56 HKT 4 use this vincenty calculation for more accurate positioning: which gives this location : 22.3104181° N 114.2186257° E (assuming mooncalc 's moon azimuth is correct, convert to its back angle, ie 58.47 degrees) Using planit: so these different approaches have a discrepancy of 100 to 200 metres.(ellipsoid model WGS84 ok?) suggestions: -calibration day: do some site survey to verify the co-ordinates, and if location is suitable, a few days or week before. better to have some landmarks for aligning the camera, eg corner...