Open AccessSolar infrared spectral observations around the 1999 solar eclipse
Author(s) -
Ridgelely A
Publication year - 2000
Publication title -
astronomy & geophysics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.168
H-Index - 22
eISSN - 1468-4004
pISSN - 1366-8781
DOI - 10.1046/j.1468-4004.2000.00223.x
Subject(s) - solar eclipse , corona (planetary geology) , physics , infrared , coronal loop , observatory , coronal hole , eclipse , astronomy , nanoflares , coronal mass ejection , astrophysics , atmospheric sciences , solar wind , astrobiology , plasma , quantum mechanics , venus
An experiment was performed at the Roseland Community Observatory, Cornwall, during the 11 August 1999 total solar eclipse. The main objective was to search for strong infrared coronal lines with a view to identifying candidates for subsequent coronal magnetic field measurements. In particular we hoped to measure the intensity of the Si IX line at 3.93 ?m, the most likely candidate line. The secondary aim of the experiment was to search for Rydberg transitions of neutral hydrogen and helium in the corona, previous observations of the infrared corona having produced evidence that cool, in coronal terms, material may co‐exist in the corona with the hot (10 6 K) plasma. The experiment did not succeed in the above aims as the Sun was obscured by cloud on the morning of the eclipse at the Roseland Observatory site. However, infrared observations of the sunlight scattered through the clouds produced a remarkable result. The infrared intensity fell precipitously 6.5 minutes before second contact and rose just as suddenly 6.5 minutes after third contact. The authors are unable to explain this result but suggest that it might be a terrestrial atmospheric rather than a solar phenomenon. Intriguing observations from the total solar eclipse in Cornwall last year are reported by A Ridgeley, B Sheen, G Barnard, C Corrigan, G E Derbyshire, R Jones, P Moir‐Riches, C Purchase, P D Read and T Richards.