Surgery should never be done during Mrityu or Ganda Yogas. Favor Ayushman (Long life) or Sukarman (Virtuous action).
The calculator's value is multifold:
While we usually use 27 Nakshatras, this Chakra uses . sarvatobhadra chakra calculator
The chakra is constructed by drawing 10 vertical and 10 horizontal lines, creating a central Varaha Mihira – Medium Outer Ring: Surgery should never be done during Mrityu or Ganda Yogas