mcp-stargazing

Calculate the altitude, rise, and set times of celestial objects (Sun, Moon, planets, stars, and deep-space objects) for any location on Earth, with optional light pollution analysis.

Features

• Altitude/Azimuth Calculation: Get elevation and compass direction for any celestial object.
• Rise/Set Times: Determine when objects appear/disappear above the horizon.
• Light Pollution Analysis: Load and analyze light pollution maps (GeoTIFF format).
• Supports:
  • Solar system objects (Sun, Moon, planets)
  • Stars (e.g., "sirius")
  • Deep-space objects (e.g., "andromeda", "orion_nebula")
• Time Zone Aware: Works with local or UTC times.

Installation

pip install astropy pytz numpy astroquery rasterio geopy

Usage

Calculate Altitude/Azimuth

from src.celestial import celestial_pos
from astropy.coordinates import EarthLocation
import pytz
from datetime import datetime

# Observer location (New York)
location = EarthLocation(lat=40.7128, lon=-74.0060)

# Time (local timezone-aware)
local_time = pytz.timezone("America/New_York").localize(datetime(2023, 10, 1, 12, 0))
altitude, azimuth = celestial_pos("sun", location, local_time)
print(f"Sun Position: Altitude={altitude:.1f}°, Azimuth={azimuth:.1f}°")

Calculate Rise/Set Times

from src.celestial import celestial_rise_set

rise, set_ = celestial_rise_set("andromeda", location, local_time.date())
print(f"Andromeda: Rise={rise.iso}, Set={set_.iso}")

Load Light Pollution Map

from src.light_pollution import load_map

# Load a GeoTIFF light pollution map
vriis_data, bounds, crs, transform = load_map("path/to/map.tif")
print(f"Map Bounds: {bounds}")

API Reference

celestial_pos(celestial_object, observer_location, time) (src/celestial.py)

• Inputs:
  • celestial_object: Name (e.g., "sun", "andromeda").
  • observer_location: EarthLocation object.
  • time: datetime (timezone-aware) or Astropy Time.
• Returns: (altitude_degrees, azimuth_degrees).

celestial_rise_set(celestial_object, observer_location, date, horizon=0.0) (src/celestial.py)

• Inputs:
  • date: Timezone-aware datetime.
  • horizon: Horizon elevation (default: 0°).
• Returns: (rise_time, set_time) as UTC Time objects.

load_map(map_path) (src/light_pollution.py)

• Inputs:
  • map_path: Path to GeoTIFF file.
• Returns: Tuple (vriis_data, bounds, crs, transform) for light pollution analysis.

Testing

Run tests with:

pytest tests/

Key Test Cases (tests/test_celestial.py)

def test_calculate_altitude_deepspace():
    """Test deep-space object resolution."""
    altitude, _ = celestial_pos("andromeda", NYC, Time.now())
    assert -90 <= altitude <= 90

def test_calculate_rise_set_sun():
    """Validate Sun rise/set times."""
    rise, set_ = celestial_rise_set("sun", NYC, datetime(2023, 10, 1))
    assert rise < set_

Project Structure

.
├── src/
│   ├── celestial.py          # Core celestial calculations
│   ├── light_pollution.py    # Light pollution map utilities
│   ├── utils.py              # Time/location helpers
│   └── main.py               # CLI entry point
├── tests/
│   ├── test_celestial.py
│   └── test_utils.py
└── README.md

Future Work

• Add support for comets/asteroids.
• Optimize SIMBAD queries for offline use.
• Integrate light pollution data into visibility predictions.

Key Updates:

1. Light Pollution: Added light_pollution.py to features and API reference.
2. Dependencies: Added rasterio and geopy to installation instructions.
3. Project Structure: Clarified file roles and test coverage.

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