Shiva Purana
यावत्संगवकालं तु धनुर्मासो विधीयते । धनुर्मासे निराहारो मासमात्रं जितेंद्रियः ६७ ।
Rites in Dhanurmāsa (month of Dhanus) prescribed for the morning can be performed upto the Sangava time (3 muhūrtas from sunrise). A brahmin shall observe fast in the month of Dhanus and restrain all his senses.
english translation
yAvatsaMgavakAlaM tu dhanurmAso vidhIyate । dhanurmAse nirAhAro mAsamAtraM jiteMdriyaH 67 ।
hk transliteration by Sanscript