Hi there,
Sorry to take so long to post.
I had one of these for a review a while ago. Appeared in Astronomy Now I think. My memory of the equipment was that the tube was luggable, would go nicely on an HEQ5 and yielded good clean images. I liked it – though the focuser was only just adequate – and quite heavy. It made a very affordable alternative to the hideously overpriced ED or triplet refractors that are unable to bring all the light to focus at one point, giving it an edge in creating luminance images.
I think the PDS needs to be used with something like a Baader coma corrector when combined with a large CCD sensor, but there was minimal coma seen when imaging with a Starlight H18.
Obviously, the secondary mirror supports generate diffraction spikes around bright stars, but brought up in the pre-SCT era I have no problem with that.
I rather fancy a 300PDS. Would be okay on my EQ6 Pro. 🙂