6” reflectors can be a little ungainly when mounted atop a tripod, especially for beginners. Many 6” f/4 and f/5 reflectors are optimized for imaging purposes, though it’s hard to find one bundled with a mount that’s actually up to the job for serious long-exposure astrophotography. You might want to consider perusing our OTA rankings page, picking out an optical tube, and then choosing a matching mount separately.
#2. Celestron Advanced VX Series 8″ Newtonian GoTo
#3. Explore FirstLight 203mm Newtonian with EXOS2GT GoTo Mount