I think this will interest you Rick.
The past couple weeks have been limited for good skies, but I had two nights in a row last weekend with excellent conditions and minimal Moon interference.
I had an AP130 setup on the EQ mount to help determine how sharp the APM150ED is in excellent seeing.
The AP130's focal length is close enough to use similar powers, but I made a 140mm aperture mask for the 150's to bring the focal ratio closer to the 130 and help sharpen the image on brighter objects.
On stars brighter than 6th mag. the 150's are not as sharp as a high quality Apo due to slight flaring, possibly from the prisms. Dimmer stars appear close enough to the 130 that the mask is not necessary.
The aperture masks minimize the flaring on bright stars, and also cut back the glare on bright planets.
The 150's objectives appear to be well figured and show very sharp Airy Disks which I find not typical of binoculars, but more common in binocular telescopes.
With the aperture masks in place I would put the 150's equal to the APM120 in regard to star sharpness at low powers and better than the 120 at high powers likely due to the well figured objectives.
I spent several hours in the early AM both nights viewing binary stars from 82x up to 275x, and was amazed at how well the 150's performed. The main difference to the 130 is a small amount of flare around the Airy Disks with the 150. Without the aperture mask the flare increases slightly, but not enough to blur the Disk.
Clean splits of binaries down to 1.8" separation are easy for the 150 and I'm sure it can do better.
Saturn was at it's highest for my region, allowing some good views at 165x using the 3-6 Nagler's despite the low angle. The image quality in the 150 was excellent. Not quite as perfect as the AP130, but more relaxed with both eyes.
Five of the moons were visible in the 150 at 103x, while the dimmest one remained elusive in the 130.
Another impressive view with the 150 was open clusters M11 and NGC7789 with the 12.5 Doctor's at 66x. The amount of tiny perfect looking stars in both is spectacular.
NGC7789 actually looks very much like a rose, while M11 takes on a three dimensional quality that extends out much further than I've seen in smaller apertures.
That combination of power, field size and two eyes with the 150 is my favorite way to view open clusters in particular.
The Scutum region is incredible to pan across using the 14mm Delos at 58x. The 150 brings out the true density of stars that occupy this region. You can pan around for hours and lose track of time very easily.
There was also an interesing pattern of satellites moving past the bottom edge of M11 that took on the appearance of a triangular shaped ship seen from an angle.
I'm planning on the AP160 for the next session to see how bright the images are of DSO's compared to the 150's.
Edited by ZX12, 10 June 2019 - 11:08 PM.