Surya Siddhanta
अतो नाक्षत्रोच्छ्रयस् तासु ध्रुवयोः क्षितिजस्थयोः। नवतिर् लम्बकाम्शास् तु मेरावक्षाम्शकास् तथा॥
Hence there is in those cities no elevation of the pole, the two pole-stars being situated in their horizon ; but their degrees of co-latitude (lambaka) are ninety : at Meru the degrees of lati- tude (aksha) are of the same number.
english translation