Locking screw on focuser

[N3ptune]

Last night I had a surprise, my focuser was stuck, not moving the eyepiece anymore (at first I thought it was frozen or broken) then I discovered it was because of that locking screw. But what is exactly the purpose of locking the focuser? I bet it must be related to photography but is it useful in visual also?

Just checking

Also, the knobs were still turning while the tube stayed still, was this bad for the mechanism?

[D4N]

Yes it is to stop the weight of the camera shifting the focus once set.  For visual it isn't much use as the focuser is unlikely to move on its own with an eyepiece on it and since you change eyepieces a lot you have to keep re-focusing anyway.

[N3ptune]

1 minute ago, D4N said:

Yes it is to stop the weight of the camera shifting the focus once set.  For visual it isn't much use as the focuser is unlikely to move on its own with an eyepiece on it and since you change eyepieces a lot you have to keep re-focusing anyway.

Ah oki then it's settled.

But it is bad to turn the knobs when it's locked? because sometimes it's unavoidable. Or could I simply remove this lock nut if it of no use for visual?

[D4N]

I would remove it, they also get removed when you do a motor focus mod as you can do damage to either the focuser or the motor unit if it is locked.

[Steve Ward]

It will not damage anything as it's just a friction drive , no teeth or gears involved to get ground up ... 

I'd leave it in place because you just know that when you eventually stick a camera on it ( oh yes you will eventually ) you'll be swearing when you can't find it ... 

[AlistairW]

On 26 December 2016 at 18:41, D4N said:

I would remove it, they also get removed when you do a motor focus mod as you can do damage to either the focuser or the motor unit if it is locked.

Oh - I didn't realise this - i have a Lakeside focuser and still have the Tension Screw up tight - I am now right in thinking this is a mistake ?

[D4N]

3 hours ago, AlistairW said:

Oh - I didn't realise this - i have a Lakeside focuser and still have the Tension Screw up tight - I am now right in thinking this is a mistake ?

I think you will be putting undue wear and tear on the focuser and motor.  It's a bit like holding the focuser still then turning the knobs, you just wouldn't do that.

The stepper motor locks when not moving anyway so you shouldn't get anything moving.

[SonnyE]

The screw is not a 'Locking Screw', it is a dampening adjuster. Even when fairly tight, my fine focusing knob can override it.

Where having it comes in very handy is when the telescope is near vertical, and you worked your buns off achieving focus, so the weighted tube, filter, and camera don't shift and screw up your focus.

If you don't want to use it, just leave it very lightly engaged. So the adjustment screw is there for when you decide, "HEY, I NEED that!" Because one night you will appreciate its value.