Short answer: No, that would not be a proper “Navkarsi pachkhan.”

A few simple points:

1. What is Navkarsi?

Navkarsi means: - No food or water the whole night. - First intake (food/water) only after about 48 minutes after sunrise the next morning. ( jainknowledge.com)

1. Condition from previous evening:

For Navkarsi to be “shuddh” (proper): - You should normally do at least Tivihar/Chauvihar (stop food, and usually water, from sunset) the previous day. - If you keep eating/drinking late at night, the next morning’s Navkarsi loses its full religious value. ( jainknowledge.com)

1. Your specific question (11 pm pachkhan):

- Taking “Navkarsi pachkhan” at 11 pm while you still do ratri bhojan (night eating) is not the traditional way. - Proper pachkhan for Navkarsi is taken in the evening before or around sunset, with the clear resolve: - “From now till tomorrow Navkarsi I will not take any food/water (as per my vow).”

1. If you can’t yet leave ratri bhojan fully:

- Step by step is fine: - First try: no food after sunset (start Tivihar). - When that becomes stable, add: no water after sunset (Chauvihar). - Then your Navkarsi the next day becomes “saintly style” and meaningful. ( jainknowledge.com)

1. Health note:

- If there is any medical issue, adjust the vow accordingly; ahimsa includes care of your own health. ( jainknowledge.com)

So:

• Navkarsi pachkhan taken at 11 pm while still doing ratri bhojan is not recommended in Jain maryadā.
• Better to fix the evening practice (no food after sunset) first, then take Navkarsi pachkhan near sunset and observe full night-up-to-Navkarsi fasting.

You can read more about these timings and rules here:

• Navkarsi time and calculation
• Tivihar and Chauvihar meaning