My astronomy project:
Repair and adjusting focus friction

Content:

Repair the friction coupling:

1. Introduction focuser
2. Disassembling the focuser
3. The friction parts
4. Assembling focuser together
5. Implement of high friction surface
6. Spring compensation load
7. To be continued

Related projects:

• Repair and adjusting focus friction
• Tangent arm focuser
• Rack and Pinion focuser
• Push and Pull focuser
• Focus and camera rotator
• Focus and temperature drift

Note:
I take no responsibility or liability for what are written here, you use the information on your own risk!

1: Introduction focuser

It's very common focuser today have a friction coupling, that's fine and give very smooth focusing compare to a rack and pinion focuser. But problems can arise if you have heavy load on the focuser, a camera or similar. I have problem with that, when telescope is pointing upwards the friction coupling slips and can't move the camera. I have adjusted the force that regulate the friction and got it a little bit better. Sometimes when the telescope get wet because of moister the problem get worse, the water act as a lubrication between the friction surfaces.

Now I decided to take the focuser apart and see if there is something wrong or something that I can rebuild and make it better. My focuser is a 3" dual speed mounted on a TS130 APO refractor, this is a special option, normally there is a 2.5" focuser on this telescope.

Here are some information about focusers:

• https://en.wikipedia.org/ wiki/ Crayford focuser Crayford focuser, Wiki
• https://en.wikipedia.org/ wiki/ Dual speed focuser Dual speed focuser, Wiki

I have built a compact motor focuser to my telescope. It's not so easy to see that there is a focuser down there.

As usual I will spend another day working with my telescope, luckily me I feel to some degree it's fun.