I kinda thought that might be the case. I’ve never seen a digital SLR with a mirror hold-up.
If ya look at the scope, you can see my junk yard steel plates holding everything up...It's all mounted to junk yard 1/2" steel plate...lol
The battery 110v power supply cost me 50 bucks used.. But worth every penny...
The light pollution filters were pricey, but to do without them, imaging suffers.
What's sad, is all these millions of kids in America, few have ever seen the Milky Way, (An arm of our own galaxy) and more every year will start losing that sight and their night sky's, simply due to poorly designed lighting fixtures.
Mirror lock is sometimes burried in the menus. It is on my Canon 20D. But most high end and prosumer models have it.