This setup appears to work quite a bit better than the previous setup I had in terms of usage. I had a Coronado double stack with two Etalons married together. And two tilt tuners (one on each). There were a lot more ghost suns to deal with. But it still worked OK. Just seems like this one is a bit better. Maybe because of the one being internal pressure tuned and the other being the external.
Well, one-off comparisons are difficult to make hard and fast rules about. First thing I note is the Coronado's appear to be 40 mm, and a 10 mm diameter increase at this aperture is significant. Having an internal pressure tuned etalon makes adjustments significantly easier. And lastly, if these were Meade Coronado etalons - well lets just say there is a considerable level of performance variance that can take place compared to the original Tucson and Isle of Mann Coronado filters.
I've only had the 50 for a few weeks and just received the DS. Had it out this morning and in SS mode I could see one tiny prom. When I added the DS the image darkened quite a bit and the prom disappeared. Ran the DS tuner through the limits but nothing. I eventually removed the DS and the image brightened and the prom popped back into view. This is new to me, when you add the DS do you have to readjust the pressure tuner also?
No you do not have to readjust the pressure tuning to double stack - provided you are on-band to begin with the PT etalon. Double stacking will always decrease the level of transmission of the filter system, making faint prominences even fainter. The transmission is the product of both of the filters transmissions. If both etalons had an 80% transmission, the cumulative transmission is 0.8 x 0.8 = 0.64 > 64%. The removal of parasitic continuum from the Sun's disc is why you double stack - and results in much greater detail from improved contrast.
Click for larger.
So for prominences, single stacking is sometimes preferable, but for disc details, double stacking is the way to go. There are ways to improve the brightness of double stacked views, and have the best of both worlds. PM me if you are interested.