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tooth_dr

Focuser slippage

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I’ve never had any issues in the past but last night was my first proper session with new EFW. Focused using a mask but then noticed the subs were out of focus after a few were taken. Rechecked and the focus was off so the focuser must have slipped

Whats the next step? It’s an ED80 DS-Pro.

Edited by tooth_dr

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Is it the original focuser? If so, it's a fairly simple tweak to get it tightened up.

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The extra weight of the FW obviously caused this, but a tweak on the tension screws should sort it, put all your kit in place and point scope pretty much straight up, then manually turn focus knob by hand all the way in and out slowly, and look for any slippage, you can also feel it slip, and adjust if needed, take it to the point just beyond slippage, you may notice the focus knob a bit tighter afterwards, but this is normal..

:)

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2 hours ago, LightBucket said:

The extra weight of the FW obviously caused this, but a tweak on the tension screws should sort it, put all your kit in place and point scope pretty much straight up, then manually turn focus knob by hand all the way in and out slowly, and look for any slippage, you can also feel it slip, and adjust if needed, take it to the point just beyond slippage, you may notice the focus knob a bit tighter afterwards, but this is normal..

:)

Thanks William. I noticed last night it wouldn’t wind in past a certain point, the knobs turned but the focuser tube didn’t move up (imaging Pac-Man so quite straight up orientation). I had to support the imaging gear with my hand to get it to the focus point.

I will try to tighten later ??

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3 hours ago, Spikey said:

Is it the original focuser? If so, it's a fairly simple tweak to get it tightened up.

 

Yes it’s the original focuser. I’ll look into tightening it up! Thanks. 

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This video will show you how to improve you're focuser. I did the same on my old ED80.

 

Just beat me to it ?

 

Steve

Edited by sloz1664

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2 hours ago, Sleepy Kiki said:

There's another mod for the SW stock focuser that's a bit more involved. 

 

 

 

2 hours ago, sloz1664 said:

This video will show you how to improve you're focuser. I did the same on my old ED80.

 

Just beat me to it ?

 

Steve

 

 

Thanks guys.  I'll try the tension screw first, then file it if not better.

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On 20/09/2018 at 13:32, Sleepy Kiki said:

There's another mod for the SW stock focuser that's a bit more involved. 

 

 

Pretty much what I discovered on my Skywatcher Equinox 120- my post on the subject in 2013......

When I dismantled my Equinox 120 focusser I found the flat, black metal part was not 'flat' at all. There was a build up of paint and/or anodising towards the edges which meant the adjusment rod only touched in two small areas. Net result- not able hold focus. This is a well documented & common fault with 'lower end' Crayford type focussers. You can easily check the flattness of said part by offering up a known straight edge (e.g. a steel rule) against the light.

A bit of delicate work with a new, fine honing stone (check this for flatness too) and frequent checking with the straight edge soon got rid of excess paint/anodising. I now have an ugly bare aluminum surface, but it works as it should and can hold a pro sized DSLR without shifting. So no need to go and buy myself some new fancy focusser!

Not good in a scope that sellls for £1400.......

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On 20/09/2018 at 12:07, Peter Drew said:

The old "elastic band" trick solves these problems.   ?

May I ask ...What is the elastic band trick ?

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You just attach one end of a band to something on the drawtube such as a diagonal and the other end to a fixed item on the focus mount. with a suitable elastic tension, the load on the drawtube is balanced, resulting in a smooth slip free motion.   ? 

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