Fifty nights.

Dr Odette Collis, retired mathematics teacher and volunteer astronomer at the Cartwright Observatory, has now documented the Greymoor Highland luminous phenomenon on every clear night since 3 February. Her 44th observation notebook — a hardback A5 exercise book, identical to the ones she used in her classroom for thirty-one years — was filled on Saturday. She began the 45th on Sunday, noting that the glow was visible by 9:40 PM, twenty minutes earlier than its usual emergence.

“It is not dimming,” she wrote, in the precise cursive that her former pupils would recognise. “It is not steady. It is growing.”

Her photometric readings, taken with the portable instruments loaned by the Royal Institute, now show the glow at approximately 30 per cent brighter than her first observation. The rate of increase has been gradual but consistent across the entire observation period, with no night of reversal. The spectral signature remains unchanged: ionised nitrogen and trace sulphur dioxide, consistent with superheated gases escaping through fractured rock.

Professor Elara Whitstone, President of the Royal Institute, confirmed on Monday that she has received a letter from Professor Aldous Nettleford of Caldwell University — the nation’s leading authority on continental geothermal systems — requesting access to Collis’s full photometric dataset. Nettleford, who is scheduled to deliver the second of the Polytechnic spring lectures on 15 April, has written that the Greymoor data “bears comparison with patterns observed in the Edgeminster thermal fields prior to the activation of the Blackmoor vents in 1897.”

The Blackmoor vents — a series of geothermal fissures that opened in the hills above Edgeminster in the winter of 1897 — were preceded by approximately three months of faint luminous atmospheric phenomena, documented at the time by a local schoolmaster named Elijah Farrow. The vents themselves, when they opened, released superheated steam and sulphurous gas for several weeks before subsiding. No lives were lost, though a significant area of pastureland was rendered temporarily unusable.

Whitstone described the comparison as “instructive but not predictive.” She emphasised that the Greymoor system’s geology differs substantially from the Edgeminster thermal fields, and that any comparison requires the data from the monitoring station — which does not yet exist.

On that front, there is progress. Gerald Northcroft, managing director of Northcroft Instruments in Edgeminster, reported on Monday that fabrication of the station’s core equipment is running ahead of schedule. The three broadband seismometers have completed factory calibration. The atmospheric gas sampling units are in final assembly. The photometric array — which will replace Collis’s portable readings with continuous automated measurement — has passed its bench tests.

“Delivery to the Greymoor site by 10 April,” Northcroft said. “Possibly the 8th, if the crating goes well.”

Installation, however, requires the access road from the Dunvale road to the station site — a 2.3-kilometre graded track that has not yet been approved. The Works Committee meets on 9 April to consider Dr Bernard Coates’s proposal. Gareth Penn, whose Highfield Farm lies along the proposed route, supports it. Isobel Dallow, whose sheep graze the ridge, does not.

Collis, characteristically, is focused on the data rather than the logistics. She will observe again tonight, weather permitting. The forecast is clear. The 45th notebook has 46 pages remaining.

“I have been watching this ridge for fourteen months,” she said. “The glow has been there for fifty nights. Something beneath the Greymoor Highlands is doing something it has not done in living memory, and we do not yet have the instruments to tell us what.”

She looked toward the ridge, faintly visible through the afternoon haze.

“Fifty nights is a long time for a question to go unanswered.”