ZWO EAF not moving camera

[Lee_P]

Hi all, I've installed a ZWO EAF onto a TS Optics 8" RC using the FLO-recommended 2" GSO Linear Bearing / TS Monorail adapter. The EAF initially seems to be working, but it doesn't always actually move the camera. It's as if it doesn't have quite enough power, although it's only moving a 2600MC-Pro and a filter holder. (The same EAF handled this fine on a previous imaging rig). Any ideas..?

 

Edited August 11, 2022 by Lee_P

[Lee_P]

Oh hang on. I think I've got it -- needed to tighten the screw underneath.

[Lee_P]

Hmm I take it back -- tightening that screw helped, but the EAF is still having trouble, particularly pulling the camera up against gravity.

[StevieDvd]

Are the fine/coarse knobs still turning okay but the focus tube not moving as expected?

You should check the focuser with the eaf disconnected (leave in place but loosen the grub screws so the focuser can be turned freely manually)

If the focuser slips when vertical and used manually the EAF won't solve that.  Otherwise the coupler may not be gripping correctly on the focuser and/or motor spindles - are you using the correct size coupler?

[scotty38]

Seems to me like the EAF is connected just fine to the spindle but that the focuser itself needs adjusting. I don't know if it's a R&P or not but certainly looks like it's slipping.

[Lee_P]

Thanks for the help! I swapped out the adapter kit-supplied cylindrical thingy for one that came with the EAF. That seems to have helped. But I'm not convinced by the quality of the supplied focusser. I'll give it a good go, but I've a feeling I'll need to splash more cash on an upgrade. I really don't like this "getting everything to work" stage of new kit, I much prefer the initial excitement, and eventual satisfaction when everything sings in harmony 😂

 

[StevieDvd]

The couplers that come with the kit shoould have one end for the motor side and various sizes for the focuser spindle. I ensured the focus spindle was a tight fit before the grubs screws were tightened and that one of the grub screws on the motor tightened against the flat side of the motor spindle.

If the adapter is using the bolts which hold the focuser spindle in place they may need tightening a tad more to regain the grip.

[scotty38]

14 minutes ago, StevieDvd said:

The couplers that come with the kit shoould have one end for the motor side and various sizes for the focuser spindle. I ensured the focus spindle was a tight fit before the grubs screws were tightened and that one of the grub screws on the motor tightened against the flat side of the motor spindle.

If the adapter is using the bolts which hold the focuser spindle in place they may need tightening a tad more to regain the grip.

But as I mentioned the spindle seems to be fastened ok as you can seen the opposite end (including the fine focus knob) spinning just fine yet the tube is not moving so it's just slipping.

[Richard_]

Was the telescope focuser functioning just fine before you put the EAF on? Watching your video it appears that the rotation of the EAF is translating to the rotation of the focuser shaft because you can see the coarse and fine knobs on the opposite side rotating just fine.

However, there is no movement of the focus tube when the shaft rotates so that is where the problem may lie. I'm only familiar with R&P focusers, so if this is also an R&P type focuser I would first check to see if the gear of the focus shaft is correctly meshing with the rack on the focus tube. 

Image 1 (the gear which meshes with the rack is at the top of the picture, this is from my refractor) 

 

Image 2 (random image from Internet, showing the rack on the underside of a focus tube. The above gear meshes with this) 

[StevieDvd]

OK so looking up the details of the Monorail focuser you gave earlier shows that it's not a rack & pinion type, more like an improved crayford (a bit like the first  Baader steeltrack versions - which are now rack & pinion).  The friction adjustment is made using the larger middle screw underneath the focuser from the TS page for the monorail "...With the middle screw of the "quincunx", only the friction is adjusted."

With that in mind do the same test but tighten the middle screw slowly and see if the focuser then starts to move. If that works you may want to draw a line on the screw head to save the position. Personally I'd do the adjustment without the EAF connected and tighten it so vertical movement is positive and not over-tight. The check it once the EAF is re-connected.

It's a bit extreme to replace the focuser if an adjustment solves the issue. My Baader was fine once adjusted, both manually and wih a Lakeside motor fitted.