I just love the idea of 3D printed DPAC eyepieces. What a perfect application. Sure, you have to program it but once that's done, just crank them out. I did mine the old fashioned way with wood, glue, scroll saw, drill, paint and tweezers to remove the splinters, no bandages......yet.
I'll post a picture of my eyepiece and set up. Not nearly as nicely crafted as Paul's but it works just fine.
I've tested a bunch of refractors and have learned a great deal. None, so far, have been dogs, but I've pretty much weeded those out already.
I have begun retesting with the red and blue LEDS today and the results are really cool and informative. I'm going to start a log and take notes of results including subjective evaluations of SA in R,G, B, "smoothness" and zones at focus", and astigmatism.
I have also evaluated to a limited degree the effects of diagonals in the light path, especially my Baader/Zeiss T2 prism diagonal.
One very nice surprise so far (but not really as I new it was a good lens) has been my good old 6" F10 Istar achromat. Truly excellent SA in G&R with a very small amount in B, a very smooth figure and no astigmatism. Excellent.
I'm still trying to figure out what's the best way to use my Canon 6D to take a few photos. With mine, I think I will need to do it manually, but I have to crack the menu code again. Funny, my simple 15 year old early Olympus digital camera seems to work just fine.
A few observations and lessons learned so far.
1. This is easy to do really, once you are all set up. I cycled through at least 6 refractors in a couple of hours.
2. I will need the pot to reduce the LED brightness, especially the R&B. Right now I'm using a neutral density filter and R&B filters.
3. The green LED has a fair amount of yellow in its spectrum so I also use a medium green filter too.
4. Using filters not only reduces the brightness a bit but also narrows the pass band, giving sharper bars. I can't detect any distortions from the filters.
5. I need to clean my flat.
6. With the brightness of the un-filtered LEDs, aligning everything is really easy as I can shift the scope around a little so that the return spot on the grating is right above the LED source.
7. As some have mentioned, the camera can introduce its own SA. Easy to see when comparing the shot to the live eye view. The cheap Olympus seems very neutral in that regard.
8. I need to clean my flat.
More to come.