Anna Prasanam
Muhurth is fixed in 2 steps shown as 2 rules tables below.
  1. Find the days suitable in a month.  Select the day. This is based on Month, Day, Nakshatra, Tithi, Yoga, and Karana. 
  2. Find the time of the event. This is based on the horoscope of that moment. What is rising ? What is setting or going to set ? etc.
Select Year and Month for finding suitable muhurth days.

Year       =   Month    =    

Janma Nakshatra of child =     Find                  

                  

Annaprasana. Choroon. This Sanskar is performed on sixth month , when the child gets solid food for the first time. Mantras recited and oblations are offered to the various deities.  With Annaprasana, it is believed that those flaws are removed, that arise due to intake of impure food in fetus. 

No. Good Avoid
1 6,8,9,10 or 12th month from birth Janma Nakshatra of child
2 Day = Th Fr Mo   
3 Nak = Revathi, Punarvasu, Mrg, Hast, Asvini, Chitra, Shravan, Svati, Rohini, Anuradha, Pushya, Shatataraka, Uthara, Utharashada, Uttarabhadrapad or Dhanishta Nak=Bharani, Kartika, Thiruvathira, Ayilyam, Makham, Pooram, Vishakham, Thrikketta, Mulam, Pooratam, Poororuttati
4 Lag = 2,9,11,7,6,5,4,3 Lag = 1,12 or 8.
Lag = Metam, Meenam, Vrischikam. 
Lag = Sun and Moon Rasi 
Lag = Vish Drekkanam
5 Tithi = 2,3,5,7,10 or 13 4,9,14, amavasya, S8 and K8, 12
1st half of K7, S1 and P15
2nd half of K3,K10 and S11
6   Mars in 8. 
7   Jup in 4.
8   Moon or Mer in 9. 
8   One planet in 10.
9   Ulka = Eclipse day. Earthquake day. Meteor Shower day. Animal howling day.