select q3c_ang2ipix(0, 0); 
select q3c_ang2ipix(0, 91); 
select q3c_ang2ipix(0, 90); 
select q3c_ang2ipix(-1, 0); 
select q3c_ang2ipix(359, 0); 
select q3c_ang2ipix('nan'::double precision,0);
