Add satellite ephemeris calculator app with Streamlit

- Implement main app logic in and for satellite ephemeris calculation.
- Add utility functions in for computing ephemeris and fetching TLE data.
- Add utility functions in for timezone conversion.
- Include dependencies in .

app.py

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+import os
+import streamlit as st
+import pandas as pd
+from geopy.geocoders import Nominatim
+from streamlit_folium import st_folium
+import folium
+from datetime import datetime
+import pytz
+from timezonefinder import TimezoneFinder
+
+from utils.satellite_utils import compute_ephemeris, fetch_custom_tle
+from utils.timezone_utils import get_abbreviated_timezone
+
+def main():
+    st.title("Satellites Ephemeris Calculator")
+
+    # Dropdown for satellite category selection
+    satellite_categories = {
+        'Starlink Generation 1': 'https://celestrak.org/NORAD/elements/supplemental/sup-gp.php?FILE=starlink&FORMAT=tle',
+        'Starlink Generation 2': 'https://celestrak.org/NORAD/elements/supplemental/sup-gp.php?FILE=starlink&FORMAT=tle&VERSION=2',
+        'OneWeb': 'https://celestrak.org/NORAD/elements/supplemental/sup-gp.php?FILE=oneweb&FORMAT=tle',
+        'Kuiper': 'https://celestrak.org/NORAD/elements/supplemental/sup-gp.php?FILE=kuiper&FORMAT=tle',
+        'Custom Satellite': None
+    }
+    satellite_type = st.selectbox("Select or Search Satellite", list(satellite_categories.keys()))
+
+    custom_tle = None
+    satellite_url = satellite_categories[satellite_type]
+
+    # If custom satellite is selected, ask for satellite name or NORAD ID
+    if satellite_type == 'Custom Satellite':
+        satellite_name_or_id = st.text_input("Enter Satellite Name or NORAD ID:")
+        if satellite_name_or_id:
+            custom_tle = fetch_custom_tle(satellite_name_or_id)
+
+    # Detect user's local time zone
+    local_timezone = datetime.now().astimezone().tzinfo
+
+    # Coordinates and time input
+    with st.container():
+        col1, col2 = st.columns([2, 1])
+        with col1:
+            use_address = st.checkbox("Use Address to Set Location", value=False)
+            if use_address:
+                address = st.text_input("Enter Your Address:")
+                if address:
+                    geolocator = Nominatim(user_agent="satellite-observation-app")
+                    try:
+                        location = geolocator.geocode(address, timeout=10)
+                        if location:
+                            latitude = location.latitude
+                            longitude = location.longitude
+                        else:
+                            st.write("Could not find the location. Please enter a valid address.")
+                    except Exception as e:
+                        st.error(f"Error fetching location data: {str(e)}")
+            else:
+                st.write("Select your location on the map:")
+                default_location = [37.7749, -122.4194]
+                map_display = folium.Map(location=default_location, zoom_start=2)
+                folium.Marker(default_location, tooltip="Default Location").add_to(map_display)
+                map_data = st_folium(map_display, width=350, height=300)
+                if map_data and 'last_clicked' in map_data and map_data['last_clicked']:
+                    latitude = map_data['last_clicked']['lat']
+                    longitude = map_data['last_clicked']['lng']
+
+        with col2:
+            latitude = st.text_input("Latitude:", value=str(latitude) if 'latitude' in locals() else "")
+            longitude = st.text_input("Longitude:", value=str(longitude) if 'longitude' in locals() else "")
+
+            # Determine time zone from GPS coordinates
+            if latitude and longitude:
+                try:
+                    tf = TimezoneFinder()
+                    timezone_str = tf.timezone_at(lng=float(longitude), lat=float(latitude))
+                    timezone = pytz.timezone(timezone_str)
+                    current_time = datetime.now()
+                    timezone_abbr = get_abbreviated_timezone(timezone_str, current_time)
+                    st.write(f"Detected Time Zone: {timezone_str} ({timezone_abbr})")
+                except Exception as e:
+                    st.error(f"Error determining timezone: {str(e)}")
+                    timezone = local_timezone
+            else:
+                timezone = local_timezone
+                timezone_abbr = timezone.tzname(datetime.now())
+                st.write(f"Using local time zone: {timezone} ({timezone_abbr})")
+
+            start_date_local = st.date_input("Start Date (Local Time):")
+            start_time_local = st.time_input("Start Time (Local Time):")
+            end_time_local = st.time_input("End Time (Local Time):")
+
+            # Convert local time to UTC
+            start_datetime_local = datetime.combine(start_date_local, start_time_local)
+            end_datetime_local = datetime.combine(start_date_local, end_time_local)
+            start_datetime_utc = start_datetime_local.astimezone(pytz.utc)
+            end_datetime_utc = end_datetime_local.astimezone(pytz.utc)
+
+            st.write(f"Start Time in UTC: {start_datetime_utc.strftime('%Y-%m-%d %H:%M:%S')}")
+            st.write(f"End Time in UTC: {end_datetime_utc.strftime('%Y-%m-%d %H:%M:%S')}")
+
+            compute_button = st.button("Compute Satellite Positions")
+
+    # Align the table with the button
+    if compute_button:
+        if latitude and longitude and start_date_local:
+            ephemeris_df = compute_ephemeris(
+                satellite_url, float(latitude), float(longitude),
+                start_datetime_utc.strftime('%Y-%m-%d'),
+                start_datetime_utc.time(), end_datetime_utc.time(),
+                custom_tle
+            )
+            if not ephemeris_df.empty:
+                st.dataframe(ephemeris_df, use_container_width=True)
+            else:
+                st.write("No visible satellites found for the specified time and location.")
+        else:
+            st.write("Please fill in all fields (latitude, longitude, and observation time).")
+
+if __name__ == "__main__":
+    main()

app_copy.py

@@ -0,0 +1,218 @@
+import os
+import streamlit as st
+from skyfield.api import Topos, load, EarthSatellite
+import requests
+import pandas as pd
+from geopy.geocoders import Nominatim
+from streamlit_folium import st_folium
+import folium
+import numpy as np
+from datetime import datetime
+import pytz
+from timezonefinder import TimezoneFinder
+
+# Function to convert azimuth degrees to cardinal direction
+def get_cardinal_direction(azimuth_degrees):
+    directions = ['N', 'NE', 'E', 'SE', 'S', 'SW', 'W', 'NW', 'N']
+    index = int((azimuth_degrees + 22.5) // 45)
+    return directions[index % 8]
+
+# Function to get timezone in an abbreviated format
+def get_abbreviated_timezone(timezone_str, dt):
+    try:
+        tz = pytz.timezone(timezone_str)
+        return dt.astimezone(tz).tzname()
+    except Exception as e:
+        st.error(f"Error converting timezone: {str(e)}")
+        return timezone_str  # Return the original string if conversion fails
+
+# Generalized function to compute satellite ephemeris
+def compute_ephemeris(satellite_url, latitude, longitude, start_date_utc, start_time, end_time, custom_tle=None):
+    try:
+        ts = load.timescale()
+        year, month, day = map(int, start_date_utc.split('-'))
+        observer = Topos(latitude, longitude)
+        start_hour, start_minute = start_time.hour, start_time.minute
+        end_hour, end_minute = end_time.hour, end_time.minute
+        start_datetime = datetime(year, month, day, start_hour, start_minute)
+        end_datetime = datetime(year, month, day, end_hour, end_minute)
+        total_minutes = int((end_datetime - start_datetime).total_seconds() // 60)
+        times = ts.utc(year, month, day, [start_hour] * total_minutes, np.arange(start_minute, start_minute + total_minutes))
+
+        # Fetch TLE data for custom satellite or use predefined URL
+        if custom_tle:
+            st.write("Using custom TLE data for satellite computation.")
+            satellites = [EarthSatellite(custom_tle[1], custom_tle[2], custom_tle[0], ts)]
+        else:
+            r = requests.get(satellite_url)
+            with open('satellite_data.txt', 'wb') as f:
+                f.write(r.content)
+            satellites = load.tle_file('satellite_data.txt')
+
+        # Prepare the ephemeris data
+        ephemeris_data = []
+        for satellite in satellites:
+            difference = satellite - observer
+            for ti in times:
+                topocentric = difference.at(ti)
+                ra, dec, distance = topocentric.radec()
+                alt, az, distance = topocentric.altaz()
+                if alt.degrees > 0:  # Check if the satellite is above the horizon
+                    # Convert Angle objects to string representations and add cardinal direction
+                    azimuth_degrees = az.degrees
+                    cardinal_direction = get_cardinal_direction(azimuth_degrees)
+                    ephemeris_data.append({
+                        "Date (UTC)": ti.utc_strftime('%Y-%m-%d %H:%M:%S'),
+                        "R.A.": str(ra),
+                        "Dec": str(dec),
+                        "Altitude": f"{alt.degrees:.2f}°",
+                        "Azimuth": f"{azimuth_degrees:.2f}° ({cardinal_direction})"
+                    })
+
+        # Convert ephemeris data to DataFrame for display
+        ephemeris_df = pd.DataFrame(ephemeris_data)
+        if not custom_tle:
+            os.remove('satellite_data.txt')
+        return ephemeris_df
+    except Exception as e:
+        st.error(f"Error computing ephemeris: {str(e)}")
+        return pd.DataFrame()  # Return an empty DataFrame on error
+
+# Fetch TLE data for custom satellite by name or NORAD ID
+def fetch_custom_tle(satellite_name_or_id):
+    try:
+        # Correct URL formats for NORAD ID and satellite name
+        if satellite_name_or_id.isdigit():
+            # Fetch TLE by NORAD ID
+            celestrak_url = f'https://celestrak.org/NORAD/elements/gp.php?CATNR={satellite_name_or_id}'
+        else:
+            # Fetch TLE by satellite name
+            celestrak_url = f'https://celestrak.org/NORAD/elements/gp.php?NAME={satellite_name_or_id}&FORMAT=TLE'
+
+        with st.spinner("Fetching TLE data..."):
+            response = requests.get(celestrak_url)
+
+        if response.status_code == 200 and len(response.text.splitlines()) >= 2:
+            lines = response.text.splitlines()
+            st.success("TLE data fetched successfully!")
+            st.text(f"Name: {lines[0].strip()}\nTLE Line 1: {lines[1].strip()}\nTLE Line 2: {lines[2].strip()}")
+            return lines[0].strip(), lines[1].strip(), lines[2].strip()  # Name, TLE line 1, TLE line 2
+        else:
+            st.error("TLE data could not be fetched. Please check the satellite name or NORAD ID.")
+            return None
+    except Exception as e:
+        st.error(f"Error fetching TLE data: {str(e)}")
+        return None
+
+# Streamlit app
+def main():
+    st.title("Satellites Ephemeris Calculator")
+
+    # Dropdown for satellite category selection
+    satellite_categories = {
+        'Starlink Generation 1': 'https://celestrak.org/NORAD/elements/supplemental/sup-gp.php?FILE=starlink&FORMAT=tle',
+        'Starlink Generation 2': 'https://celestrak.org/NORAD/elements/supplemental/sup-gp.php?FILE=starlink&FORMAT=tle&VERSION=2',
+        'OneWeb': 'https://celestrak.org/NORAD/elements/supplemental/sup-gp.php?FILE=oneweb&FORMAT=tle',
+        'Kuiper': 'https://celestrak.org/NORAD/elements/supplemental/sup-gp.php?FILE=kuiper&FORMAT=tle',
+        'Custom Satellite': None
+    }
+    satellite_type = st.selectbox("Select or Search Satellite", list(satellite_categories.keys()))
+
+    custom_tle = None
+    satellite_url = satellite_categories[satellite_type]
+
+    # If custom satellite is selected, ask for satellite name or NORAD ID
+    if satellite_type == 'Custom Satellite':
+        satellite_name_or_id = st.text_input("Enter Satellite Name or NORAD ID:")
+        if satellite_name_or_id:
+            custom_tle = fetch_custom_tle(satellite_name_or_id)
+
+    # Detect user's local time zone
+    local_timezone = datetime.now().astimezone().tzinfo
+
+    # Coordinates and time input
+    with st.container():
+        col1, col2 = st.columns([2, 1])
+        with col1:
+            use_address = st.checkbox("Use Address to Set Location", value=False)
+            if use_address:
+                address = st.text_input("Enter Your Address:")
+                if address:
+                    # Add User-Agent to Nominatim geocoder
+                    geolocator = Nominatim(user_agent="satellite-observation-app")
+                    try:
+                        location = geolocator.geocode(address, timeout=10)
+                        if location:
+                            latitude = location.latitude
+                            longitude = location.longitude
+                        else:
+                            st.write("Could not find the location. Please enter a valid address.")
+                    except Exception as e:
+                        st.error(f"Error fetching location data: {str(e)}")
+            else:
+                st.write("Select your location on the map:")
+                default_location = [37.7749, -122.4194]
+                map_display = folium.Map(location=default_location, zoom_start=2)
+                folium.Marker(default_location, tooltip="Default Location").add_to(map_display)
+                map_data = st_folium(map_display, width=350, height=300)
+                if map_data and 'last_clicked' in map_data and map_data['last_clicked']:
+                    latitude = map_data['last_clicked']['lat']
+                    longitude = map_data['last_clicked']['lng']
+
+        with col2:
+            latitude = st.text_input("Latitude:", value=str(latitude) if 'latitude' in locals() else "")
+            longitude = st.text_input("Longitude:", value=str(longitude) if 'longitude' in locals() else "")
+
+            # Determine time zone from GPS coordinates
+            if latitude and longitude:
+                try:
+                    tf = TimezoneFinder()
+                    timezone_str = tf.timezone_at(lng=float(longitude), lat=float(latitude))
+                    timezone = pytz.timezone(timezone_str)
+                    # Display abbreviated timezone
+                    current_time = datetime.now()
+                    timezone_abbr = get_abbreviated_timezone(timezone_str, current_time)
+                    st.write(f"Detected Time Zone: {timezone_str} ({timezone_abbr})")
+                except Exception as e:
+                    st.error(f"Error determining timezone: {str(e)}")
+                    timezone = local_timezone
+            else:
+                timezone = local_timezone
+                timezone_abbr = timezone.tzname(datetime.now())
+                st.write(f"Using local time zone: {timezone} ({timezone_abbr})")
+
+            start_date_local = st.date_input("Start Date (Local Time):")
+            start_time_local = st.time_input("Start Time (Local Time):")
+            end_time_local = st.time_input("End Time (Local Time):")
+
+            # Convert local time to UTC
+            start_datetime_local = datetime.combine(start_date_local, start_time_local)
+            end_datetime_local = datetime.combine(start_date_local, end_time_local)
+            start_datetime_utc = start_datetime_local.astimezone(pytz.utc)
+            end_datetime_utc = end_datetime_local.astimezone(pytz.utc)
+
+            st.write(f"Start Time in UTC: {start_datetime_utc.strftime('%Y-%m-%d %H:%M:%S')}")
+            st.write(f"End Time in UTC: {end_datetime_utc.strftime('%Y-%m-%d %H:%M:%S')}")
+
+            # Compute button
+            compute_button = st.button("Compute Satellite Positions")
+
+    # Align the table with the button
+    if compute_button:
+        if latitude and longitude and start_date_local:
+            ephemeris_df = compute_ephemeris(
+                satellite_url, float(latitude), float(longitude),
+                start_datetime_utc.strftime('%Y-%m-%d'),
+                start_datetime_utc.time(), end_datetime_utc.time(),
+                custom_tle
+            )
+            if not ephemeris_df.empty:
+                # Display the dataframe with use_container_width to match the app width
+                st.dataframe(ephemeris_df, use_container_width=True)
+            else:
+                st.write("No visible satellites found for the specified time and location.")
+        else:
+            st.write("Please fill in all fields (latitude, longitude, and observation time).")
+
+if __name__ == "__main__":
+    main()

requirements.txt

@@ -0,0 +1,9 @@
+streamlit
+skyfield
+geopy
+pandas
+numpy
+pytz
+timezonefinder
+requests
+folium

utils/satellite_utils.py

@@ -0,0 +1,96 @@
+import os
+import streamlit as st
+from skyfield.api import Topos, load, EarthSatellite
+import requests
+import pandas as pd
+import numpy as np
+from datetime import datetime
+
+def get_cardinal_direction(azimuth_degrees):
+    """
+    Converts azimuth degrees to cardinal direction.
+    """
+    directions = ['N', 'NE', 'E', 'SE', 'S', 'SW', 'W', 'NW', 'N']
+    index = int((azimuth_degrees + 22.5) // 45)
+    return directions[index % 8]
+
+def compute_ephemeris(satellite_url, latitude, longitude, start_date_utc, start_time, end_time, custom_tle=None):
+    """
+    Computes the ephemeris for the satellite.
+    """
+    try:
+        ts = load.timescale()
+        year, month, day = map(int, start_date_utc.split('-'))
+        observer = Topos(latitude, longitude)
+        start_hour, start_minute = start_time.hour, start_time.minute
+        end_hour, end_minute = end_time.hour, end_time.minute
+        start_datetime = datetime(year, month, day, start_hour, start_minute)
+        end_datetime = datetime(year, month, day, end_hour, end_minute)
+        total_minutes = int((end_datetime - start_datetime).total_seconds() // 60)
+        times = ts.utc(year, month, day, [start_hour] * total_minutes, np.arange(start_minute, start_minute + total_minutes))
+
+        # Fetch TLE data for custom satellite or use predefined URL
+        if custom_tle:
+            st.write("Using custom TLE data for satellite computation.")
+            st.write(f"Custom TLE Data:\nName: {custom_tle[0]}\nTLE Line 1: {custom_tle[1]}\nTLE Line 2: {custom_tle[2]}")
+            satellites = [EarthSatellite(custom_tle[1], custom_tle[2], custom_tle[0], ts)]
+        else:
+            r = requests.get(satellite_url)
+            with open('satellite_data.txt', 'wb') as f:
+                f.write(r.content)
+            satellites = load.tle_file('satellite_data.txt')
+
+        # Prepare the ephemeris data
+        ephemeris_data = []
+        for satellite in satellites:
+            difference = satellite - observer
+            for ti in times:
+                topocentric = difference.at(ti)
+                ra, dec, distance = topocentric.radec()
+                alt, az, distance = topocentric.altaz()
+                st.write(f"Checking time {ti.utc_iso()} - Altitude: {alt.degrees:.2f} degrees")  # Debugging statement
+
+                if alt.degrees > 0:  # Check if the satellite is above the horizon
+                    azimuth_degrees = az.degrees
+                    cardinal_direction = get_cardinal_direction(azimuth_degrees)
+                    ephemeris_data.append({
+                        "Date (UTC)": ti.utc_strftime('%Y-%m-%d %H:%M:%S'),
+                        "R.A.": str(ra),
+                        "Dec": str(dec),
+                        "Altitude": f"{alt.degrees:.2f}°",
+                        "Azimuth": f"{azimuth_degrees:.2f}° ({cardinal_direction})"
+                    })
+
+        # Convert ephemeris data to DataFrame for display
+        ephemeris_df = pd.DataFrame(ephemeris_data)
+        if not custom_tle:
+            os.remove('satellite_data.txt')
+        return ephemeris_df
+    except Exception as e:
+        st.error(f"Error computing ephemeris: {str(e)}")
+        return pd.DataFrame()  # Return an empty DataFrame on error
+
+def fetch_custom_tle(satellite_name_or_id):
+    """
+    Fetches TLE data for a custom satellite by name or NORAD ID.
+    """
+    try:
+        if satellite_name_or_id.isdigit():
+            celestrak_url = f'https://celestrak.org/NORAD/elements/gp.php?CATNR={satellite_name_or_id}'
+        else:
+            celestrak_url = f'https://celestrak.org/NORAD/elements/gp.php?NAME={satellite_name_or_id}&FORMAT=TLE'
+
+        with st.spinner("Fetching TLE data..."):
+            response = requests.get(celestrak_url)
+
+        if response.status_code == 200 and len(response.text.splitlines()) >= 2:
+            lines = response.text.splitlines()
+            st.success("TLE data fetched successfully!")
+            st.text(f"Name: {lines[0].strip()}\nTLE Line 1: {lines[1].strip()}\nTLE Line 2: {lines[2].strip()}")
+            return lines[0].strip(), lines[1].strip(), lines[2].strip()  # Name, TLE line 1, TLE line 2
+        else:
+            st.error("TLE data could not be fetched. Please check the satellite name or NORAD ID.")
+            return None
+    except Exception as e:
+        st.error(f"Error fetching TLE data: {str(e)}")
+        return None

utils/timezone_utils.py

@@ -0,0 +1,13 @@
+import streamlit as st
+import pytz
+
+def get_abbreviated_timezone(timezone_str, dt):
+    """
+    Converts the timezone string to an abbreviated format.
+    """
+    try:
+        tz = pytz.timezone(timezone_str)
+        return dt.astimezone(tz).tzname()
+    except Exception as e:
+        st.error(f"Error converting timezone: {str(e)}")
+        return timezone_str  # Return the original string if conversion fails