Dual speed focusers

[wulfrunian]

When we get this much cloud I spend too much time browsing possible new toys for the scope... anyway, I was just wondering what advantages there were in having a dual speed focuser, as opposed to the standard one I've got fitted. Is this just an advantage for imagers or intended for visual too?

[Breakintheclouds]

Michael,

I've just bought a new dual-speed. It simply makes focusing much more precise and accurate (and easy), and is definitely something to consider for visual use.

You won't feel much benefit with wide views, but if you've tried looking at small objects like Mars you'll know how difficult it can be to make tiny tweaks back and forth with a single-speed focuser

[brianb]

I was just wondering what advantages there were in having a dual speed focuser, as opposed to the standard one I've got fitted.

Do you have difficulty in getting an exact focus because there's only a hair of movement between "in too far" and "out too far"? If so you'll benefit from a dual speed focuser. You might only need help when using a very high power; the coarse action of the standard focuser is usually OK when viewing at low or medium power.

For imaging, an electric powered focuser is more important than the extra sensitivity of the dual speed type. The reason being that you don't have to touch the focuser - which causes vibrations making it harder to get an accurate focus. OTOH playing "hunt the hand control" can be an irritant; electric focusing for the sake of electric focusing is IMO a Bad Idea .

[wulfrunian]

Thanks, that helps, think it's something to put on the wish list