|
The main reason a refractor will show an Airy disc when a nearby reflector doesn't is because of its piddling aperture, not its magic powers of trans-physics resolution. I have yet to see a refractor (and I own a few) that gives a 'textbook ' as in Suiter's textbook star test. In fact, owing to the inherent spherical and chromatic aberration in even an 'exquisitely figured' triplet it is very hard to interpret the star test.
Likewise, one of my 4" f15 achromatic scopes will split Antares - only because the secondary star falls in the minimum between the central dot and the first airy ring.
Again, Mark is bang on the money. The average punter at a public observing night is not impressed by the concept of averted vision- my experience is that less than 5% will 'get it'. Nor will they remark on the glorious airy disc or high contrast views. After watching plenty of people go through Perth obs over the last few years, the C14 usually gives the best 'wow', and the Meade 16 a close second, usually because of the target on display.
Pity a gem can't be managed in the dome. I'm now worried about when our Lx200 gives up the ghost.
Cheers,
Andrew.
|