Both my pressure tuned Lunts had sweet spots. You have to ‘clock’ the double stack filter to alter the sweet spot and reveal detail. Perhaps they are more even than the tilt models though.DeepSolar64 wrote: ↑Sat Jun 06, 2020 5:17 am My SMII90, actually a 102 in SS works wonderfully on proms and limb detail but so far is only so-so on disc detail. It's really bright. But the resolution it gives on the limb is outstanding. In DS it gives decent views but seems to be harder to tune than the 60. I can't look through the eyepiece at the same time I am twiddling the tuner. Arm is not long enough!
I am surprised that the Solarscope would give a more even tuned field than the Lunt scopes unless you are talking about one of their tilt-tuned models. Their pressure tuners by what I have read tune more evenly giving less of a sweet spot. Coronado scopes are tilt-tuned and have pronounced sweet-spots. At least mine does. The SMII 60 seems more so than the SMII 90.
The fact you can use high magnification says a lot too. On my Coronado SMII60, especially in DS I have to stick with lower powers. Detail just disappears with high magnification. I use the 25mm Cemax and 19mm Lunt eyepieces the most giving 16 and 21.5 power. I rarely ever use anything over 50x. The SMII 90 is a different animal. 100x and over is possible with good seeing.
That does seem low power for your SM60. Great that you can now crank it up with the 90.