hɪz mˈeɪn ˈɪntɹɛsts wɜː ɹˌeɪdɪəɡɹˈæfɪk stˈʌdiz ʌvðɪ ˌʌpɚɹ ˈætməsfˌɪɹ ænd ðə sˈʌn, ðˌoʊ hɪz mˈeɪn kˌɑːntɹɪbjˈuːʃənz wɜː θiəɹˈɛɾɪkəl.
His main interests were radiographic studies of the upper atmosphere and the sun, though his main contributions were theoretical.