I am looking for words of wisdom, currently own a 8 inch reflector on a HEQ5 mount and a 16 inch Dob using argo navis. I have some change in my pocket and looking to buy a 120 x 1000 refractor or a 150 x 1800 Mak to be used on the EQ mount. It will mainly be used for visual work or maybe (i say maybe) low level astro photography. I am aware of the CA in the refractor which to me should not be a issue. The main reason for the change something quick and easy to place on my EQ mount. So which one, I am all ears. Cheers Laurie
A 120 x 1000 refractor is a considerable size of log. Because it's so long, some viewing angles could be uncomfortable, especially near the zenith. The Mak would be lighter and more comfortable to view through.
Having a 150x1800 Mak on that I utterly love (also on an HEQ5Pro mount) I'm obviously biased, but I think you need to consider this:
If you want to get your feet wet with imaging consider a shorter focal length scope like an ED80. Long focal lengths add demands and complexity and may not be the easiest rig to start out on. Big unwieldy tubes like a 120/1000 refractor are hard to tame beasts, too.
If you're not worried about imaging, the 6" Mak will perfectly complement your big Dob, and likely replace your 8" Newt. I haven't got a big Dob, but between my 6" Mak and my 8" Dob the Mak gets almost 100% of the observing time. The Mak is just so much more pleasant to use and look through, despite the effort of setting up the EQ mount every time I want to use it. I'm only keeping the Dob because there is little gain in selling it. Now, I should mention that I'm mostly interested in narrow-field stuff. However, with your big Dob you've got the wide field covered anyway.