As far as I can understand, this is mostly a public domain site with electronic libraries. Books are free to download, but they are not copyrighted because most of them date from the end of the last century or earlier and are quite large in terms of megabytes.
These are mostly good quality scans converted to PDF, although many are also in formats suitable for e-readers like Kindle and ePub, although they don’t convert very well on my Sony e-reader, at least. So I recommend PDF.
Pandit Sanjay Rath । Jyotish Guru
Sanjay Rath (उड़िया: ସଞୟ ରଥ) comes from a traditional family of astrologers in Puri, whose lineage traces back to Sri Achyuta Das (Achyutananda). Sanjay Rath uses the Brihat Parashara Horashastra, Jaimini Upadesha Sutra, Brihat Jataka, and Kalyanavarma's Saravali as the foundation of his astrology, and draws on various other Jyotish scriptures. His overall teachings and writings span various schools of thought, although he has not created his own brand of astrology.