Takahashi FC-100DC focuser

[mikeDnight]

If you get the screws unevenly tightened you'll get noticeable image shift, so carefully does it! The top screws need to be precisely and equally tightened. After you've removed the pinion and loosened the top screws equally, move the draw tube in and out by hand. It should be loose! Then tighten each screw gradually and equally until you get the level of tension you're happy with, then 're fit the pinion assembly. Check for image shift by focusing on a distant target on the horizon. If there is image shift, the tension on the top screws is uneven. It may require you to unscrew the grub screws and start again. With my FC100DC, I unwound each grub screw until its top was level with the top of the focuser body. Then I turned each screw equally, counting the turns, until the tension was how I like it. All the time I kept checking for image shift. I think it took me three attempts before I got rid of the image shift that resulted from my attempt at lessening the factory set tension, which I found to be too stiff.

[F15Rules]

On 19/01/2019 at 18:19, Saganite said:

 

All great advice above ?.

If you want a relatively cheap microfocus capability, the Baader 1.25" to T2 microfocusing eyepiece holder is worth trying. 

I've just got a pair for using with my binoviewer..as my eyes have slightly different focus points, I can now focus each eyepiece independently of each other until each eye focuses to the best sharpness I can detect. You can of course use just a single focusing eyepiece holder for cyclops viewing.

As the eyepiece holder has a T2 female thread on one end, you need a T2 male -1.25" nosepiece to attach to the eyepiece holder so that the assembly will accept your eyepiece at one end and fit into your focuser or diagonal at the other..you get c6 mm of fine focus (ideal for high power fine focusing) just by turning the knurled barrel and the bottom screw locks focus in place.

See photos below☺:

Photo 1 shows the T2 female to 1.25" nosepiece (available on eBay - search "1.25" to T2 / 31.7m Eyepiece insertion to M35 Prime Telescope Adapter Black, cost £3.22 each delivered from China!)

Photos 2  and 3 show the Baader focusing eyepiece holder (Baader part #2408195 ) and then threaded into the nosepiece.

Photo 3 show a Parks Gold Series 25mm eyepiece inserted into the focusing eyepiece holder.

It's not an FT or Moonlite dual speed, but it only costs a fraction of either of these - around £34 for the focusing ep holder and around £4 for the nosepiece.

Dave

 

[F15Rules]

Here's a couple of my FS128 under the stars tonight, first time for what seems like ages, with binoviewers loaded.with a pair of Morpheus 17.5mms and baader microfocusers☺.

M42 was a wonderful sight with this combination?.

Dave

[Rainmaker]

I just recently adjusted the draw tube glides of both of my TSA102s to get that perfect action.

I am am actually using Feathertouch Micro Pinion Assemblies on them (one came with the scope, the other I already had in my parts bin).

Smooth as Silk !!!