I am not an astro-photographer but your exposure timing is too long, I think. The central details are all gone. Cut it down to bring out more details in there. The photo should look better. Cheers
Pentax has been a niche premium photography company for year, having been commissioned to build a custom made telescope for our Science Centre as a gift from the Japanese government when Singapore gained independence and became a Republic. And now, they continue that trend with their consumer 300mm ...