‘First light’ question already settled

A109 Light Utility Helicopter flight with mayor Gisborne City from the air in November 2023.

Opinion

The work to determine whether Gisborne is the first city to see the light of a new day has been done several times in the past, so I was surprised to see Saturday’s Gisborne Herald article.

In the 1990s, as preparations for marking the millennium were being made, various places laid claim to be the first to see the sunrise on New Year’s Day.

The claimants included Hawke’s Bay, Apia in Samoa, and Mount Hikurangi.

As a longstanding contributor of astronomical items to The Gisborne Herald and other media, I used science and computer software to settle the question beyond doubt.

The calculations and printed plots were done in 1997 — and I still have a record of this work.

Saturday’s article disappointed me in that it did not give a correct explanation of the science.

Crucial to knowing when the sun rises at any given location is the tilt of the Earth, not the flattened spherical shape of the planet nor the curvature of the surface.

Currently Earth is tilted at an angle of 23.5 degrees off vertical and it is this tilt (known as axial obliquity) that gives Earth its seasons and its daily progressing sunrise and sunset times.

The Sun does not “move” into the Northern or Southern Hemispheres — that is the visual illusion caused by both the tilt and Earth’s yearly elliptical orbit around the Sun.

These days anyone can use the internet to look up sunrise times at virtually any location on Earth, and with a few adjustments, make comparisons.

Taking into account daylight saving times in Samoa and New Zealand, and that Samoa changed its time zone, New Zealand was, and still is, the first territory to be touched by the New Year sunrise. Gisborne remains the First City to See the Light.

Using www.timeanddate.com anyone can find that Gisborne is first to see the light from about November 11 through to February 4. For the remainder of the year Apia has the honour.

When I produced my calculations in 1997, I followed up by showing where the New Year sunrise could be seen in Gisborne. This was used by the Year 2000 Project to locate and build the beachfront stage just past Pacific Street for the celebrations which included Dame Kiri Te Kanawa and the NZ Symphony orchestra. It is now a much-used carpark and viewpoint.

As an aside, the first pieces of New Zealand territory to see the New Year sunrise are: (from first place down) Mount Galloway in the Antipodes Islands, Mount Hakepa on Pitt Island, Mount Hikurangi, Mount Te Kapu at Mahia, Mount Tapuaenuku in the Kaikouras, Pakarae Hill, Tatapouri Hill, Makorori Hill, Gisborne’s Town Hill, Te Mata Peak, Mount Cargill Dunedin, Gisborne beachfront at sea level, Napier City waterfront.