Omega0 said:
What diameter had your lens or mirror?
Would you describe as a darker blue or more a light tone?
10" (ten inch, i.e., 254 mm) Meade LX200-ACF. Native focal length: 2540 mm (@ f/10)
Various eyepieces from ~24 mm to 8 mm. A 2x Powermate (think of it as a Barlow lens) may have been involved too. So magnifications from around ~100x to ~500x.
Viewing with a lower power eyepiece brings a higher probability of having background stars in the field of view, allowing you to get a good comparison between the color of Neptune and the color of other stars in view. In that case, the brilliant blue of Neptune is unmistakable.
A higher power eyepiece will of course make Neptune's disk look a little bigger. But even at 10", my setup is not big enough to resolve any weather on Neptune. It still looks blue though. But without any background stars for comparison, it's difficult to judge how blue it actually is, since your eyes adjust to the color. But it's pretty deep blue, comparitively speaking anyway.
All that said, Neptune is a really beautiful shade of blue. It's difficult to put into words, except to say it's breathtaking.
For comparison, Uranus is bigger and brighter, and also blue, but Uranus's blue is closer to sky-blue. Slewing to Neptune, you'll see a smaller/dimmer object, but that Neptune blue just takes your breath away.
