https://discord.gg/DarkMatters should be open for everyone, yes. Maybe the welcome channel is readonly (not sure). You might want to scroll down to the channels dedicated to GraXpert:
Hey astronomers and astrophotographers, looking for a new, thriving community to discuss all things astro? We have just the thing for you! Astronium is a rapidly growing Discord server designed for stargazers, astrophotographers, and space enthusiast...
Active astronomy community offering posting privileges unlike current channel.
Whether you are a casual stargazer or an experienced astrophotographer, Cosmic Hub is the place for you. We are a welcoming community of people from all skill sets who are united under the shared love and curiosity for the cosmos. Cosmic Hub brings t...
Welcoming astrophotography community that may allow member participation and posting.