Duel speed focuser advice needed

[spaceboy]

Hi Everyone

With regards to duel speed focuser's and the low profile version are they any improvement over standard crayford for visual. I can understand the benefits for astrography even more so with the low profile focuser but would it be worth getting the low profile for visual? I guess given good seeing a duel speed may help get the view tack sharp but even then how often do we get ideal seeing to warrant the expense over just taking a little slower turn of the knob on a crayford. Is there any other benefit to the duel speeds? I see they have indexed draw tubes, again I can see the benefit for imaging but maybe less for visual.

Any advice would come in handy.

Thanks

SPACEBOY

[ollypenrice]

I find my two speed devices a bit too slow on 'slow' for visual, to be honest. Maybe on the planets but in general I don't think there's need for two speed in visual.

Olly

[brianb]

I find my two speed devices a bit too slow on 'slow' for visual

Not an issue since you can use the fat knob & get coarse action if you want it.

If you find you need only a tiny, tiny tweak to get from one side of nearly in focus to the other side of nearly in focus, you will benefit from a two speed focuser. Some scopes are fine with a single speed focuser, especially if you fit oversize knobs. Some aren't.

[ollypenrice]

Not an issue since you can use the fat knob & get coarse action if you want it.

If you find you need only a tiny, tiny tweak to get from one side of nearly in focus to the other side of nearly in focus, you will benefit from a two speed focuser. Some scopes are fine with a single speed focuser, especially if you fit oversize knobs. Some aren't.

In truth I would like something between the two for visual! (I'm talking mainly about the big Feathertouch here.) I love it for imaging though. Fussy so and so aren't I...

Olly

[brianb]

I would like something between the two for visual!

I sort of know what you mean; the fine action of the Feathertouch dual speed replacement focuser I have on my C11 is just about right when using a high power eyepiece but way too fine at low power; whilst the coarse action is a bit too coarse even at low power. My WO FLT 110 is about the same; but my Lunt 60mm tube seems about spot on with the fine ratio.

I wonder why 10:1 rather than 5:1 or 4:1?

Anyhoo ... an electric focuser is good for imaging ...

[spaceboy]

Cheers guy! Sounds like the money would be better spent on an EP.

SPACEBOY

[Chris H]

I have a Moonlite CR2 and use it just for visual and I love it. The ability to fine tune the focus especially on planets is great and the low speed knob requires such a gentle touch that it does not shake the scope. I would never go back to a single speed.

[ollypenrice]

Good point from Chris if your mount is a bit marginal for the wieght-focal length of your setup.

Olly

[johninderby]

In general a replacement dual speed crayford will be of better quality that the standard focusers that come with a SkyWatcher dob

The key advantages are:

1. Smoother more precise focusing.
   
2. Virtually no slop in the drawtube as you move it in or out.
   
3. More accurate collimation of your scope as when you collimate with the drawtube in one positon it won't change when you move the drawtube in or out.
   
4. The fine focus knob requires only a light touch of your fingertip to move it, hence reduced vibration of the scope whilst focusing and particularly with a dob less likelihood of intentionally moving the scope.
   
5. More durable.
   

So yes, upgrading your focuser will improve it for visual use with improved collimation particularly if you're using a laser collimator.

John

[GazOC]

I've found a dual speed focuser for visual to be one of those non-essential things that I now don't want to do without. Before they became commonplace I was more than happy with a single speed R&P but I guess I'm spoiled these days and a dual speed Crayford is usually the first "extra" I buy for a scope.

[spaceboy]

?

Gonna have to flip a coin on this one