It's taken me a year to put the system together (ASA DDM60 Pro mounting, TEC 140 telescope, FLI CenterLine filter wheel and FLI ML16803 camera) but I achieved a very quick "first light" set of exposures using the TEC 140
last night. Just 5 x 200 second unguided lights of the Pleiades
through a blue filter. The Pleiades were already getting pretty low to the horizon before I had to get back to work calibrating the mounting. The raw data is quite noisy, I haven't got any "flats" yet so any vignetting is uncorrected and the extreme contrast in brightness probably means that when I return to this subject I'll not only need more exposures but for best results may need to fine tune the exposure time to reduce star bloat. I'll also definitely need to sharpen up my processing skills but hopefully the brightest stars will get a bit tighter when I can add red and green data as well. Anyhoo, enough apologizing! Here's the result, uncropped except for the loss of 48 pixels on each border and then downsized to a forum friendly 768 x 768 pixels:
The field of view is about 2° edge to edge or 3° corner to corner (for comparison the full Moon is about half a degree) and looking at the original 4096 x 4096 images stars are tight and circular right to the corners of the field and even though the mounting hadn't been retrained for the new configuration unguided tracking was perfectly good for the 200 seconds it took to capture each frame. And the good news for my future convenience is that focusing was entirely automatic courtesy of MaximDL working in conjunction with the Starlight Instruments motorized focuser I retrofitted to the TEC 140 'scope. I'm also happy enough that despite the relatively slow f/7 focal ratio the ML16803 camera (working at -25°C) was able to capture the reflection nebulosity relatively easily. Hopefully it will be clear again tonight so it will be back to calibration work pointing at 30 plus stars and fine tuning the pointing accuracy so that the software controlling the mounting can compensate even better for residual polar alignment errors, flexure in the telescope and atmospheric refraction. The aim is to be able to achieve, at need, at least 1,000 seconds unguided exposures when that's completed!