Leif said:
A UV filter should be clear according to Leica. Anyway, that's what they recommend. Bahhhhh. (That was a sheep noise.)
Incidentally you asked about what to look at in the night sky. I recommend the planets: Jupiter, Saturn and Venus are all prominent. Look for bright 'stars' on the plane travelled through the sky by the sun and moon, and if a 'star' has a disk, it's a planet.
Jupiter: very bright, look ~SE, elevation ~45 degrees. At least 2 bands should be seen and 4 moons at 60x.
Saturn: fairly bright, look S, elevation ~50 degress. Rings wide open. Gap between rings and planet easy at 60x. Cassini division in ring visible?
Venus: very bright, W elevation ~30 degrees and setting not long after the sun. Looks like a half moon.
We should have a clear sky sometime this decade.
I think the planets would be a wonderful comparison for your scopes, and my Televid! I wonder how your little Swaro 65 would do?
I believe that a "Skylight"-filter is the same as a UV-filter, it's just a different name.
As to using the planets as a scope test: Good idea!
I have the Nikon Spotting Sope 80A (Sky&Earth in the US) on trial, and I have used it to look at the planets. I can borrow a Swaro AT80HD to compare to a really good scope (and I have done so, but not with the nightsky as the target).
Here's what I can see with the Nikon:
Jupiter:
The four moons can be seen throughout the zoom range all the way from 20x to 60x. It is possible to barely discern that the planet has bands (at 60x), but it is quite difficult. I suspect a better scope would show bands with ease.
Saturn:
Can see the gap between rings and planet itself at 60x, but it is plain impossible to discern the Cassini division with this scope.
Venus:
This planet is so bright that some color fringing will show, no matter where in the view the planet is. Center will be best, naturally. It is easy to se the disc and the half-moon shape of the planet at 60x.
Moon:
The moon is a thankful object to look at, since it is quite big, and almost fills the view at 60x with this scope. Details at the moon surface is easy to see, and the brightness is not causing much trouble with color fringing, although some will be visible at the moon edges.
I'm still trying to decide whether I will keep this scope or step up to a more expensive scope. The color fringing is annoying me slightly in high-contrast situations, and details are a bit muddy at 60x and at large distances, but I have only compared it to the Swaro that I mentioned, and this is a top-class scope compared to the low-end Nikon.
What I can say is that I don't think the price difference matches the quality difference. I'd say the Nikon offers good value for money.
Best regards
-Øyvind