.i. Tar eis a derbtha duinn d'arrmainntibh egintaca & d'fidracaib geomitreachta gorab on grein soillsigter an re & na h-airdrinnacidh uili, foillseocamaid anois cad o tic dorcadus nadurtha ar in re re n-abarthar eclipsis. Agus adermaid d'innsaidhi an adbhur sin, os on n-grein gabus an re a solus & nac fuil ni ele ann da boinfed an solus sin de ac an talman, gorab e scaili na talman, bis co direc idir an grein & in re, tet a dimcill an re & benas solus na greine dhe & is e an dorcugad sin an re o scaile na talman is eclipsis ann. Agus teagmaidh se co nemmeallta an gach en mi caithi oir gac uair tecmas an re do ceann no derball na Dreaguine, curtar annsa line n-direc e ar cert comair na greine & na talman & tollaidh se co cert scaili na talman & dorchaidter uili e. Et an trath gluaisis an re da deiscert no do tuaiscert an scaili sin, seachnaidh se an t-eclipsis uile & gibe taeb dib sin a m-baininn se ris an scaili sin, an med bis fai an scaili de, as i an meidi sin bhis d'eclipsis eir sin.
Agus is ime sin ata da gne d'eclipsis ann .i. eclipsis uneuersalis .i. eclipsis coitcinn & eclipsis particularis .i. eclipsis rannaighi. Agus is uime sin nach inann aimser
Eclipsis na plained ele. As plained acu fein as cuis d'eclipsis na plained ele, oir is e an plained as isli dorchaides an plained is airdi. Et ar in nos cedna, as e an re dorcaidhes iat uili uair ele fa sec . Da cur a n-dobart a cell ar eclipsis nis mo dogen fidair gheomitric annso tis as a ticfither an t-eclipsis co follus.