When is Bheemana Amavasya? Wiki is here

Bheemana Amavasya is a festival celebrated in South India, mostly in parts of Karnataka, Andhra Pradesh and Tamil Nadu. It is celebrated on the new moon day (amavasya) of the ashadha month of the Hindu calendar.

About Ashadha :

Ashadha o is a month of the Hindu calendar that corresponds to June/July in the Gregorian calendar.[1] In India's national civil calendar, this month is the fourth month of the year, beginning on 22 June and ending on 22 July. In Vedic Jyotish, Āsāṛh begins with the Sun's entry into Gemini. It is the first of the two months that comprise the monsoon season. The corresponding month in the Bengali calendar, Aṣaṛh (Bengali: আষাঢ় "Monsoon"), is the third month. In lunar religious calendars, Āsāṛh begins on a new moon and is usually the third month of the year.

How is Bheemana Amavasya celebrated? Rituals on Bheemana Amavasya :

Two clay structures are made and a yellow thread is tied around it. Women pray by giving offerings followed by a traditional song. Later, women tie the yellow thread (Kankana) to their right hand and pray to Bheemeshwara. Amavasya is the day of no moon occurrence. Any fortnight containing the new-moon is considered auspicious by Hindus.

They believe that during this period, their offerings reach their forefathers and in return offerants are blessed. It signifies the beginning of auspicious period, and many pooja's are performed to Hindu deities seeking blessing. The last day of Ashada is marked as the very auspicious Bheemana Amavasya. It is believed that on this day Shiva, is impressed by Parvathi's devotion towards him and accepts her as his wife. Parvathi is considered by some schools of Hinduism as the supreme Divine Mother or Lordess and all other goddesses are incarnations or manifestations of her.

When is Bheemana Amavasya? Wiki is here

Goddess Parvathi embodies many virtues: fertility, marital felicity, devotion to the spouse, asceticism and power. It is believed if women abstain from consuming food on this day and offer prayers to Lord Shiva, Parvathi would seek a virtuous husband for unmarried women while married women would pray for their husband's long life, success and happiness.

Bheemana Amavasya :

Usually idols of Shiva and Parvathi are made using red mud clay, dried and decorated. Idols are made of panchaloha (five materials – gold, silver, copper, bronze and zinc).

It signifies the beginning of auspicious period, and many pooja's are performed to Hindu deities seeking blessing. The last day of Ashada is marked as the very auspicious Bheemana Amavasya. It is believed that on this day Shiva, is impressed by Parvathi's devotion towards him and accepts her as his wife.