Why ts[name] thing is constantly giving error in python

Question

I was making a satellite position detection project in python. But this code is throwing this error:

Traceback (most recent call last):
  File "C:\Users\soumy\OneDrive\Desktop\PySatelliteFinder\main.py", line 50, in <module>
    calculate_and_display_position(name.upper())  # Convert to uppercase for TLE lookup
    ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "C:\Users\soumy\OneDrive\Desktop\PySatelliteFinder\main.py", line 15, in calculate_and_display_position
    satellite = ts[name]
                ~~^^^^^^
TypeError: list indices must be integers or slices, not str

My Code is This:

import turtle
from datetime import datetime
from skyfield.api import Topos, load

# Function to calculate and display satellite position
def calculate_and_display_position(name):
    # Clear previous drawing
    screen.clear()
    
    # Load TLE data
    ts = load.tle_file('stations.txt')
    
    try:
        satellite = ts[name]
    except KeyError:
        screen.write(f"Satellite '{name}' not found.", align="center", font=("Arial", 16, "normal"))
        return

    # Get current UTC time
    current_time = datetime.utcnow()
    
    # Calculate satellite position
    topos = satellite.at(ts.utc(current_time.year, current_time.month, current_time.day,
                                  current_time.hour, current_time.minute, current_time.second))
    alt, az, _ = topos.observe(observer_location).apparent().altaz()

    # Display satellite name, position, and local time
    screen.write(f"Satellite: {name}\n"
                 f"Altitude: {alt.degrees:.2f} degrees\n"
                 f"Azimuth: {az.degrees:.2f} degrees\n"
                 f"Local Time: {current_time}", align="left", font=("Arial", 16, "normal"))

# Create a Turtle screen
screen = turtle.Screen()
screen.bgpic("world_map.gif")  # You'll need to provide a world map image

# Create an observer location
observer_location = Topos(latitude_degrees=23.247921, longitude_degrees=87.871365)

# Initialize the Turtle
satellite_turtle = turtle.Turtle()
satellite_turtle.penup()
satellite_turtle.goto(0, 200)
satellite_turtle.hideturtle()

# Input box for satellite name
name = screen.textinput("Enter Satellite Name", "Enter the satellite name:")
if name:
    calculate_and_display_position(name.upper())  # Convert to uppercase for TLE lookup

# Listen for clicks to change satellite
screen.onclick(lambda x, y: calculate_and_display_position(screen.textinput("Enter Satellite Name", "Enter the satellite name:").upper()))

# Close the window when clicked
screen.exitonclick()

Now if i click the ok button, then its happening: The Moment When The Code Is Run, It Throws A Dialog Asking For The Name

I try separating the ts = load.tle_file('stations.txt') outside of calculate_and_display_position(name) and inside calculate_and_display_position(name), i write global ts but still showing the same thing.

I was exepecting a output where when entered the latest satellite name, the module will fetch the coordinates and make a point in the map and shows the position with the name in red.

Answer 1

Comparing your code to the examples on Skyfield’s Earth Satellites page, it looks like you are missing the line that would convert the list of satellites into a dictionary indexed by satellite name:

by_name = {sat.name: sat for sat in satellites}

Adapting to your own code, maybe:

ts_list = load.tle_file('stations.txt')
ts = {sat.name: sat for sat in ts_list}