I've been itching for a couple of years to set up my C-11 for galaxy season. I was wanting a bit more image scale for little galaxies, planetary nebulae, etc. I had mounted it for the Mars-Moon occultation in December, which of course was clouded out, and we haven't had a clear night since then. With last night being clear and the daytime temperature being above freezing, I thought I'd get everything set up.
I had purchased an adapter that would allow me to mount my filter wheel and camera onto the
OAG. Yesterday afternoon, I got that whole assembly put together, with approximate spacing, and mounted it onto the Moonlite focuser on the back of the C-11. To get the guide camera and imaging camera parfocal on the
OAG, I aimed at a tree about 200 m away. It was an old oak tree, leafless of course at this time of year, and it wasn't moving too much in the wind.
I quickly realized that the
FOV at that distance is about 5 cm! If there had been an ant crawling on one of those twigs, I could have told you the colour of its eyes. It took me a while - all twigs look alike - but I did manage to find a single leaf, which gave me something to align the finder on. I got the
OAG dialed in approximately. Depth of field is about 2 cm, so it was a bit hard to tell if I had the same twig in focus in both cameras.
And, speaking of cameras, it was hard seeing anything in the daytime. With the guide camera shooting at 0.001 s and the imaging camera at 0.01 s, through the
Ha filter (!) I was able to see the twigs.
Of course, I had some final focusing to do: finding infinity focus, and getting the
OAG focus precise. So, after dark, I want out to do that. I was able to find Jupiter and use it to crank the focuser to infinity. That's a lot of turns on an
SCT!
Then I had to get
SGP set up. There are way more settings than I remembered that needed to be changed. I have a motor on the Moonlite, but it's a DC motor, not a stepper. (I didn't know about auto-focusing back when I bought it!) The FCUSB module that drives it has an "absolute position emulation" mode, but it is a bit dodgy. And it tries to drive the motor with USB power, which requires careful fiddling with the PWM pulse width and timing settings to make the motor turn at all. I quickly realized that autofocus wasn't going to work tonight, so I dug out my 11" Bahtinov mask and focused manually.
Then plate solving didn't work. Oh, another setting: "number of tries". I ask you, what kind of brain-dead default is 1? After a few hits on that, I figured that I was on target. Now guiding... Yes, I had already changed the focal length. But I knew I needed to recalibrate. Which requires seeing a star. Nopity-nope. There are precisely zero stars showing in the guide camera. It's an old QHY5, very noisy, and now it is looking through a pinhole and
f/10 optics, instead of the
f/3.2 optics it is used to.
By this time, I was getting chilled. Setting this thing up is just too much work. I need a better guide camera. I need to upgrade the motor in the Moonlite focuser. It is time to pull the plug on this experiment.
So I am thinking that, next warm day, I'll re-build my 8" Newt setup. If I need more image scale, I'll stick a barlow on it.