function mvn_sep_ancillary_data, trange = trange, delta_t = delta_t ,load_kernels=load_kernels,maven_kernels = maven_kernels
if not keyword_set (delta_t) then delta_t = 32
tr = timerange(trange)
total_time = tr[1] - tr[0]
ntimes =ceil(total_time/delta_t)
times = tr[0] + delta_t*dindgen(ntimes)
et = time_ephemeris(times)
SEP_ancillarya = {time_UNIX: 0d, time_ephemeris:0d,look_directions_MSO:fltarr(4, 3),look_directions_SSO:fltarr(4, 3), $
look_directions_GEO:fltarr (4, 3)}
SEP_ancillary = replicate (SEP_ancillarya,ntimes)
if keyword_set(load_kernels) then maven_kernels = mvn_spice_kernels(trange = tr,/load,/valid)
tmp_MSO = mvn_sep_look_directions(utc = times, coordinate_frame = 'MAVEN_MSO')
tmp_SSO = mvn_sep_look_directions(utc = times, coordinate_frame = 'MAVEN_SSO')
tmp_GEO = mvn_sep_look_directions(utc = times, coordinate_frame = 'IAU_MARS')
SEP_ancillary.look_directions_MSO = tmp_MSO.SEP_look_directions
SEP_ancillary.look_directions_SSO = tmp_SSO.SEP_look_directions
SEP_ancillary.look_directions_GEO = tmp_GEO.SEP_look_directions
SEP_ancillary.time_UNIX = times
SEP_ancillary.time_ephemeris = et
return, SEP_ancillary
end