Sri SaiBaba said "Do Not Consult the Astrological Almanacs. Do Not Believe in astrology". The sastras and the saints say that the planetary positions and horoscopes can have an effect on us only till we surrender to a competent Sadguru, once we have surrendered to a competent Sadguru such as Baba, the planets or horoscopes can do no harm to the devotee.
Let us go through some of the incidents in Sai history.
Baba himself, pointing this out, once said to a devotee, "Where in your destiny was a child for you? I have split my body to present you with a son." Another time he said to a devotee, "What can the planets do to the children of Dwarakamayi?"
Once a famous astrologer had come, to examine Baba's physiognomy and palms and thereby verify; Baba's divinity. As he reached the Masjid and was about to sit in a corner, Baba started shouting, "Woh hamara jhompdi ka bamboo ginene ko aya. He has come to count the bamboos of my hut (the features of His body); there is nothing for him to see here. Get him out of here."
(Source: Sai Bhakti Sadhana Rahasyam Chapter - The belief in astrological almanacs how they prevent our complete surrender to Baba)
There lived in Bandra (a suburb of Bombay) a Tendulkar family, all the members of which were devoted to Baba. . The son, Babu Tendulkar was studying hard day and night and wanted to appear for the medical examination. He consulted some astrologers. Examining his horoscope they told him that the stars were not favorable that year and that he should appear for the examination next year, when he would be certainly successful. This cast a gloom over him and made him restless. A few days afterwards his mother went to Shirdi and saw Baba. Amongst other things she mentioned the gloomy and morose condition of her son, who was to appear for the examination in a few days. Hearing this Baba said to her, "Tell your son to believe in Me, to throw aside horoscopes and predictions of astrologers and palmists and go on with his studies. Let him appear for the examination with a calm mind, he is sure to pass this year. Ask him to trust in Me and not to get disappointed". The mother returned home and communicated Baba's message to her son. Then he studied hard and in due course appeared for the examination. In the written papers he did well, but being overwhelmed by doubts he thought that he would not secure sufficient marks for passing. So he did not care to appear for the oral examination. But the examiner was after him. He sent word through a fellow- student, stating that he had passed in the written examination and that he should appear for the oral. The son being thus encouraged appeared for the oral examination and was successful in both. Thus he got through the examination that year successfully by Baba's grace, though the stars were against him. It is to be noted here that doubts and difficulties surround us just to move us and confirm our faith. We are tested as it were. If we only hold on steadily to Baba with full faith and continue our endeavors, our efforts will be ultimately crowned with success. (Source: Sri Sai Satcharitra Chapter – 29)