This scraper allows you to download ALL messages from every given Telegram channel of which you are a member. As of now, you can define a specified start date and the script will download all messages from that date until present times. The data is then stored in a CSV for further analysis. Happy downloading!
You'll need an API ID and hash for your personal account. Have a look at the documentation and Terms of Service for further information: https://core.telegram.org/api/obtaining_api_id
Keep in mind that the Telgram API by default uses 2FA. Therefore, be prepared to enter your phone number and successive authentification code from your Telegram messenger