VIGNA GANAPATHI
Appearance:

Rohini Nakshatra is related to Vigna Ganapathi.
The lord wear plenty of ornaments and his complexion is of golden hue.

Vigna Ganapati is the Lord Ganesha forms and signifies as remover of obstruction, disturbance and difficulties.

In Vighna Ganapati form, Lord Ganesh appears with eight hands similar to Lord Vishnu and holds Shankha (conch) and Chakra (wheel) on both left and right upper hand.
The other hands holds his broken tusk and Modaka, noose and elephant goad, flower arrow, sugarcane and a battle axe.
Vigna Ganapatis trunk is curved with bouquet of flowers.
Mantra:

atha viGnagaNapatidhyAnaM || mudgalapurANE ||

shaMKEkShucApakusumEShukuThArapAsha |
cakrasvadaMtasRuNimaMjarikAshanAdaiH |
pANishritaiH parisamIhitabhUShaNashrI |
viGnEshvarO vijayatE tapanIyagaura H || 9 || svarNavarNaH

Mantra (Easy to read):

atha vigna ganapati dhyaanam || mudgala puraane ||

Shankheshu Chaapa Kusumeshu KutharaPasha |
chakra Swadanta Sruni Manjarikaa Sharaduhaih |
Paanishritaih Parisameehita Bhhoshana Shri |
Vighneshvaro Vijayato Tapaneeya Gaurah || 9 || svarna varnah
Mantra Translation:

Ganapati removing the obstacles". He has eight arms. He is golden in colour. His hands hold the single tusk, the disc, the arrow-flowers, the hatchet, the conch, the sugar-cane stem, the noose, the elephant goad. With the tip of his trunk, he carries a bunch of flowers (pushapamanjari).
Mantra Benefits:

Worshipping this form is believed to help devotees to remove all obstacles and bad influence. Praying to Lord every day is believed to bring prosperity. Rohini Nakshatra is related to Vigna Ganapathi.