I wanted to share an experiment I did back in April during galaxy season. I found that you can purchase very fast 8mm F/0.9 CCTV camera lenses, and with a little 3d printing these can be mounted to a sensitive guide camera such as the ASI290mm. Here's what the camera with mounted lens looks like:
My idea was to mount this entire device to a 40mm eyepiece to use with my 10" F/5 Dobsonian. Together, the telescope, eyepiece, and CCTV lens would effectively create a 10" F/1.0 system, which is four times as fast as a RASA or Hyperstar. In theory, this should allow for very short subs, and my hope was that I could get useable images even without tracking by keeping the exposure time below 1s. Here's what the eyepiece-lens-camera assembly looks like:
To test my idea, I took my telescope and "digital eyepiece" assembly to a nearby Bortle 3 observing site and tried observing a few galaxies. By stacking 0.5s exposures, I was able to get a surprising amount of detail in as little as 10s total exposure. Here are some of the results:
M51, 20x0.5s (top) and 74x0.5s (bottom)
M81 and M82, 50 x 0.5s (top) and 89 x 0.5s (bottom)
Leo Triplet (41 x 0.5s)
M101 (61 x 0.5s)
Overall, I was pretty happy with the results as well as the experience of using this setup. With the extremely fast image formation and manual telescope movement, I found it to be a lot like visual observing, except that the level of detail I could observe was greatly enhanced. Of course, you could get better images with a tracked setup and prime-focus camera, but for this experiment I was trying to create something like digital night vision. This could be useful for primarily visual observers who want to experiment with EAA, but don't want to invest in a whole new rig with tracking, etc. I can also see something like being turned into an integrated product to replace the Revolution Imager. Anyway, perhaps a fairly niche application of EAA, but feel free to discuss.