“Bamya’s themes are victory, banishing, protection and overcoming. Her symbols are light and fire. In Zoroastrian tradition, this Goddess guides the sun god Mithra’s vehicle through the sky. More important, as the Goddess of twilight, Her presence signals the beginning of today’s festival, Sada.
As the sun sets in Iran today, a huge bonfire will be ignited near a water source to symbolize the power of light to overcome darkness and the power of good over evil. For us this means accepting our power and potential to overcome and obstacles that life may bring in any season.
Too often our lives seem overwhelmed with obligations, and we find ourselves feeling lost in the seething sea of humanity. Bamya’s counsel today is to learn how to swim in that sea by recognizing the ability of one person to truly make a difference – be it within yourself, in the life of another, in a specific situation, or in the world.
At sunset today, light an orange candle (or another one the color of twilight) and greet Bamya with a prayer like this:
“Lady of the gentle twilight, I welcome you
As the sun sets on this day
let things from the past
that I no longer need
also fade away
Teach me to leave them behind
as easily as you leave behind the daylight
As darkness falls
grant rest to my unsettled spirit
so that I can rise tomorrow
renewed and whole
Bamya be with me.
(Patricia Telesco, “365 Goddess: a daily guide to the magic and inspiration of the goddess”.)
The few sites that I found that mentioned Bamya pretty much stated the same thing: “In Zoroastrian tradition, this Goddess guides the sun god Mithra’s vehicle through the sky. Also the Goddess of twilight.” 
In the The Complete Book of Muslim and Parsi Names, it states “Bāmyā: (Av) 1. shining; radiant; repsplendent. 3. deity of dawn who guides the vehicle of Mithra; epithet of the Fravashis.”  Also in this book, under Hvare, it states: Hvare: (Av) 1. sun. 3. deity of the sun who is considered fairest of Mazda‘s creations and is considered to purify the earth and all things therein. He is distinguished for powers of observation. His chariot is drawn by Bamya.”  Neither one of these entries mention whether this deity is male or female.
From the book Spiritual Body, Celestial Earth from Mazdean Iran to Shi’ite Iran, I found this entry: Siroza…Here we might mention other figures of ‘feminine Angels,’ in connection with Daena and Ashi Vanuhi;…Bamya (beaming, radiant), who drives the chariot of Mithra and the third night after death appears to the sacred soul when Mithra climbs the mountain; in Manicheism, She becomes the ‘Friend of Light’, Ushah, who bears the very name dawn; Ushahina, the special Angel of the hours between midnight and the moment the stars become visible” (Corbin, p. 280).
Gandhi, Maneka & Ozair Husain. The Complete Book of Muslim and Parsi Names, “Bāmyā“.
Gandhi, Maneka & Ozair Husain. The Complete Book of Muslim and Parsi Names, “Hvare“.
Levigilant.com, Gods List B., “Bamya“.
Bharucha, Ervad Sheriarji Dadabhai. A Brief Sketch of the Zoroastrian religion & customs, (p.xxxvii).
Hurst, George Leopold. Sacred Literature, (p. 85).
Iranpoliticsclub.net, “Persian Mythology, Gods and Goddesses“.
West, M.L. Indo-European Poetry and Myth, (p. 129).