When I had my 6" dob it didn't show much colour to me at all with stars.
In fact it was quite noticeable comparing the views thru mine to a 10" dob at the same time. I was comparing the gold star in the Jewel Box (NGC 4755) star cluster and that gold star really stood out in the 10", but was very pale in the 6". Sometimes good seeing conditions would improve the colour a little.
I couldn't even see any green colour in the Orion nebula hard as I tried (tho my daughter could- younger eyes it seems are good at picking out colour).
Then, with my first viewing thru my 10" dob, wow, coloured stars everywhere. It's the first thing that threw me that was such a huge noticeable difference. And easy to see green in the Orion nebula now!
That being said, many people do have trouble seeing star colour.
Also, interesting to note, about how we see colour in planetary nebulae- some people will see an object as blue, some as green. I've read that we see it as one or the other (I see blue). From what I understand, it's how our eyes are wired (I don't know all the details why). I really don't know why that doesn't apply to Neptune, as I think we all see it as blue... Maybe it's got something to do with the fact a PN is a DSO
.
Mental, you'll probably know why?
De-focussing helps greatly to pick out star colour. A technique I use all the time with colourful doubles to bring out more colour. It's surprising just how blue some of those stars are when that's done.
Jas, it sounds like you got Neptune. Stars have a pin point bright look about them, where as Neptune and Uranus, yes, is dull I guess the way you described it. It an even, flattish, luminence, you can make out a perfectly shaped circle rather than a point like a star (if that makes sense). Uranus reminds of a zit- perfectly round.
. Neptune is a bit smaller, but quite strikingly blue in my 10". As for Uranus, I could only just make out the green tinge on it. Yet many people say it's very green, so there you go.
And I thought I was fairly good at picking up colour these days
. As you've worked out, they do look different compared to the stars around them.
Now is the perfect time to observe Uranus as it's in its opposition period, so it's a good size and bright.
P.S.
Jas, I'd be interested to know how you go picking out the colour with the 6" aimed at
Albireo aka beta Cygni. The star is very easy to find naked eye, but once you observe it thru a scope it reveals itself as a colourful blue and gold double star. And then try de-focussing a bit to bring out more colour.
And oooh, I have another one for you that I'd curious to see if you can get- though not a star, but a galaxy.
M77 (Cetus A) in the constellation of Cetus is quite a bright face on spiral and ridiculously easy to find as it sits within a degree of delta Ceti. There you- nice little challenge for you!
I never got to observe these with my 6" so I'd love to hear your report.
