Brihat Samhita
अपरस्यां चलकेतुः शिखया याम्याग्रयाङ्गुलौच्छ्रितया । गच्छेद्यथा यथोदक्तथा तथा दैर्घ्यं आयाति ॥ ११-३३ ॥
Cala Ketu is a comet which appears in the west with a tail an inch in length pointing to the south; as it proceeds more and more towards the north, it increases in length.
english translation
aparasyAM calaketuH zikhayA yAmyAgrayAGgulaucchritayA । gacchedyathA yathodaktathA tathA dairghyaM AyAti ॥ 11-33 ॥
hk transliteration by Sanscript