Even at f/10 I try to use a threaded connection on my SCTs and not the 1.25inch nosepiece, which is a less secure connection. With a SCT to T-adapter, and T-Thread chain you'll have less vignetting than with a 1.25inch nosepiece and a more secure threaded connection. Just my 2 cents.
I agree, it makes me nervous that stuff is going fall off using the diagonal. Not sure why it didn't focus the first time I threaded it on? I'll give it another try. I'm getting more familiar with everything. I might have had something else out of whack.
I had to watch more than half a dozen videos on how to Polar Align my HEQ5. So many details, it's a little intimidating. I took it slow and followed every step, even if I knew it wasn't applicable. Like calibrating the polar scope. Unfortunately I don't have a clear view of Polaris from my back deck, it is visible from my yard, but I'd rather be on the deck for now.
I used a Polar Alignment app on my phone to assist with getting the mount into the correct position. Carefully aligned true North and set my elevation. Once it was dark I performed a 2 star calibration, then used the polar alignment option through the hand controller. It allows you to use different stars to fine tune your polar alignment. The GoTo functionality finally worked properly! I'll need to run through the process a few more times before I have it down.
I calibrated that useless little finder scope, never know when you might actually need it.
We had mostly clear skies last night and I got to put everything through its paces. The ASI294MC arrived Friday along with the focus mask. I started out on F/10 and looked at Jupiter, then added the 2x Barlow. That was neat, I could clearly see cloud patterns and 3 of Jupiter's moons.
Next I switched to F/6.3, which was a lot more friendly to work with. The imaging was a lot faster which was expected. I had no trouble getting things into a rough focus. Actually getting the focus near perfect is going to take some practice.
Lastly I swapped out the secondary mirror and added the HyperStar. One word, wow! Imaging was lightning fast, I pointed at a dark part of the sky and watched the stars pop into view. Keeping the same alignment I swapped in the high speed narrowband filter and It was obvious that it was holding back the light pollution. It did require a little extra exposure time, but at F2 it's minimal. I was very impressed. This was the reason I picked the C6 SCT and I'm glad I did. It's laughable at how complex all of this is.
All and all, I'm pretty happy with everything. I think my expectations were accurate. I'm not quite ready to drive to a dark site, need a few more nights of practice at home.
The images I have so far are not worth showing off. It's really just me calibrating and testing stuff out. Next step is to find out what's worth viewing in the Northern hemisphere this month. I'll have some images to shar soon. I'm happy to post more images of my scope, lol.