Big and fast...

[ollypenrice]

I could fancy one of these;

David Lukehurst - astronomical telescopes - Links

That's a 24 inch but look how small it is. David Lukehurst is a tall guy but even so...

The thing about ever larger Dobs is that, usually, the FL gets ever longer with the aperture so you cease to be able to frame the well loved objects in the EP. You end up viewing smaller faint fuzzies instead of larger ones with more brightness.

I wonder how bad the contrast loss would be? Anyone used a visual scope below F4? I haven't.

Olly

[Shibby]

Cor, that's ~2.5m of FL at f4!! I can only imagine what M51 would look like in something like that!

[John]

I had a peek though a 20" DL dob at the SGL5 star party. I think that was around F/4.2 - it's owner had specified the scope so he (a 6 footer) did not need a ladder or even steps to view with it. I only had a quick look at M51 and M13 but, oh boy, what views they were

But you have a 20" dob yourself so you will know all about that .....

[swamp thing]

Hi Olly

Don't know if you've seen this or not but it's worth a look.

Astromart Reviews - Observing with Webster 28" f/2.7

Regards Steve

[Mr Spock]

Hmmm, a 24" f4 and 21mm Ethos would give you an 0.88° field of view. Tempting...