Glen, I use a Powermate for (most of) my planetary imaging. I have the 2.5x as it is smaller and lighter. With the ASI224 with its 1.25" nosepiece, I've measured it coming in at f/21-22, correlating with TVs specs on surface to sensor distance.
I've also tried a Bintel ED Barlow, and can't say that I can tell the difference with such a small sensor.
|