- guiding commands
- guide scope mountings
Great little mount
I can get 0.7 arcsecond RMS guiding for payloads from 5 lbs. to 40 lbs. with this mount. The EC compensates for the wide range of payloads as long as you start with the mount in perfectly balanced in 3 axis. You do have to forget all your experiances with other mounts because they don't apply. For example, the left-right balance is hard to setup with many guide scope mountings, and you don't want to have frequent guiding commands.
From CEM25-EC to CEM40-EC
Wow. I liked my little CEM25-EC and got some great results with it, but this thing is a generation newer—and better. Everything feels crisp and tight and professional, unlike the smaller one that had some quirks and weak points. I got some great unguided exposures from the CEM25-EC as long as I got a good polar alignment—but the iPolar on this makes that a snap and thought I’ve only gotten a few clear nights to try it, the tracking is consistently good. When guiding, the PHD2 graph looks like it’s not working very hard. The go-to seems better (I’m always allowing for my own ineptitude) and the hand controller is a definite step up. I appreciate that we can plug a USB cable directly into the mount. . .but why are we still using plastic phone plugs on the hand controller? Sheesh. But that’s a small point. The USB2 port at the back of the saddle is handy, though I wish it were USB3 to match my ZWO cameras. The 12v supply is only 3 amps which is a necessity for the ASI2600 cooler, but so far it’s working fine (in moderate temps). The cable management system baffles me me—how do you get a cable down that teeny hole? But it helps a little. The new tripod seems every bit as stable as my old 2-inch iOptron tripod. The thumbscrews are a little awkward, but work fine. BUY THE MINI-PIER!!! It’ll keep you out of the cardiac ward. Apparently iOptron’s logic dictates that the RA axis does it’s job before the Azimuth axis moves. This means your camera is in danger of hitting a tripod leg, especially if you have a long rig like my TeleVue np101is. I actually did that a couple of times on the little mount, the CEM25-EC, and I’m not sure it’s impossible with the mini-pier (on either mount). But it’s a good start. Overall: it’s a great mount. It’s not as small and the CEM25-EC but still easily transportable and I can’t imagine the situation where I would prefer the little mount instead of it. The performance is superb (so far: 4 times out) and it’s a pleasure to use. Still quiet, though not as quiet as the little one. Feels more solid, though I never really had a problem with vibrations on the other one. My overall view is that there’s no reason to buy the older, smaller mount any more. Yes, this one is more expensive but the improvements make it worth it.