Sunrise/Sunset Calculation Returns None for Certain Date/Location Combinations

[laksh-krishna-sharma]

Description

The jyotishganit library fails to calculate sunrise/sunset times for certain date/location combinations, returning None values. This causes a TypeError when the library attempts to compare None with float in the compute_nathonnatabala function during shadbala calculations.

Error Details

Error Type

TypeError: '<=' not supported between instances of 'NoneType' and 'float'

Error Location

File "/opt/venv/lib/python3.11/site-packages/jyotishganit/components/strengths.py", line 498, in compute_nathonnatabala
    is_day_birth = sunrise <= birth_hour < sunset
                   ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
TypeError: '<=' not supported between instances of 'NoneType' and 'float'

Full Traceback

Traceback (most recent call last):
  File "/app/src/services/shadbala_services.py", line 200, in calculate_shadbala
    chart = await to_thread_with_context(
            ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/opt/venv/lib/python3.11/site-packages/jyotishganit/main.py", line 86, in calculate_birth_chart
    strengths.calculate_all_strengths(d1_chart, person)
  File "/opt/venv/lib/python3.11/site-packages/jyotishganit/components/strengths.py", line 176, in calculate_all_strengths
    compute_shadbala(chart, person)
  File "/opt/venv/lib/python3.11/site-packages/jyotishganit/components/strengths.py", line 187, in compute_shadbala
    compute_kaalabala(chart, person)
  File "/opt/venv/lib/python3.11/site-packages/jyotishganit/components/strengths.py", line 479, in compute_kaalabala
    compute_nathonnatabala(chart, person)
  File "/opt/venv/lib/python3.11/site-packages/jyotishganit/components/strengths.py", line 498, in compute_nathonnatabala
    is_day_birth = sunrise <= birth_hour < sunset
                   ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
TypeError: '<=' not supported between instances of 'NoneType' and 'float'

Steps to Reproduce

1. Install jyotishganit library (tested with version >=0.1.2)
2. Call calculate_birth_chart with the following parameters:

from datetime import datetime
from jyotishganit import calculate_birth_chart

birth_date = datetime(2006, 7, 8, 22, 30, 0)
latitude = 28.643364
longitude = 77.115472
timezone_offset = 5.5
name = "Test Person"

chart = calculate_birth_chart(
    birth_date=birth_date,
    latitude=latitude,
    longitude=longitude,
    timezone_offset=timezone_offset,
    name=name,
)

3. The error occurs during the shadbala calculation phase

Expected Behavior

The library should:

1. Successfully calculate sunrise/sunset times for the given date/location
2. If calculation fails, handle the None values gracefully instead of crashing
3. Provide a meaningful error message if sunrise/sunset cannot be calculated

Actual Behavior

1. Sunrise/sunset calculation returns None for this specific date/location combination
2. The library crashes with TypeError when trying to compare None with float
3. No graceful error handling for this edge case

Environment

• Python Version: 3.11
• jyotishganit Version: >=0.1.2
• Operating System: Linux (tested in Docker container)
• Location: Delhi, India (28.643364°N, 77.115472°E)
• Date: July 8, 2006
• Timezone: UTC+5.5 (IST)

Additional Context

Observations

1. Date-Specific Issue: The same location works fine for July 9, 2006, suggesting this is a date-specific calculation issue
2. Location: Delhi, India is not a polar region, so this shouldn't be a polar day/night issue
3. Library Dependency: The library appears to use skyfield/ephemeris data (de421.bsp file is downloaded)
4. Impact: This affects all calculations that require shadbala (kaalabala component specifically)

Workaround

Currently, we're handling this by:

1. Catching the TypeError and providing a user-friendly error message
2. Pre-validating sunrise/sunset calculation using the astral library before calling jyotishganit
3. Suggesting users try a different date if the exact date is not critical

However, this is not ideal as:

• Users cannot get calculations for their actual birth date
• The library should handle this gracefully internally

Suggested Fix

1. Immediate Fix: Add null checks in compute_nathonnatabala before comparing sunrise/sunset values:

   if sunrise is None or sunset is None:
       # Handle gracefully - either skip nathonnatabala calculation
       # or use a fallback method to determine day/night
       logger.warning("Sunrise/sunset calculation failed, skipping nathonnatabala")
       return
   is_day_birth = sunrise <= birth_hour < sunset

2. Long-term Fix: Investigate why sunrise/sunset calculation returns None for certain dates and fix the underlying calculation

3. Better Error Handling: Provide meaningful error messages when astronomical calculations fail

Related Information

• The issue occurs specifically when calculating shadbala, which requires kaalabala
• Kaalabala includes nathonnatabala, which needs sunrise/sunset times
• Other calculations (like panchanga, ashtakavarga) may also be affected if they trigger shadbala calculation

Verification

We've verified that:

• ✅ The same location works for July 9, 2006 (next day)
• ✅ The coordinates are valid (Delhi, India)
• ✅ The timezone offset is correct (5.5 for IST)
• ✅ The date is valid (July 8, 2006 exists)
• ✅ Using alternative libraries (astral) can calculate sunrise/sunset for this date

This suggests the issue is in jyotishganit's internal sunrise/sunset calculation logic, not in the input parameters.

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Note: This issue prevents users from getting accurate astrological calculations for their actual birth dates when the library encounters this bug. A fix would greatly improve the library's reliability and user experience.