6 replies to this topic

[Lalanke]

I am thinking to upgrade the hex 2.5 focuser of my ES ED 127 FCD 100 scope. Mainly because I am an imager, currently I attached 1.25 zwo filter wheel, zwo OAG zwo294mm, zwo EAF and hotech ff without any issue.I’m planning to move in to bigger full frame 6200mm with Zwo EAF, OAG L with 2” filter wheel with a APX reducer. Do you think it’s more convenient to upgrade the focuser with a feather touch?

[Boeglewatcher]

If the current focuser works w/o issues I assume it will work w the heavier full frame as well.

(I have installed a FT on my WO FLT132 and I love it but if the current focuser works, spend the money for something else)

cs Joachim 

[TOMDEY]

A few of us have upgraded our ES 152mm APO triplets with Feathertouch 3-inchers. The wait time from ordering to delivery is rather long. There are some other parts needed for the changeover. I'm still waiting for mine; ordered it 11 weeks ago. The ES stock hex 3-incher seems pretty junky and fell right off the OTA when I lifted it from the nice case. The ES focuser mechanical interface is a terribly cobbled mess. Looking forward to the Feathertouch! I've retrofitted several of those to various deficient OTA's.   Tom

[GeoffC47]

I have that scope and had all kinds of trouble with the focuser: focus, colimation and smoothness. I complained to ES. It took them 3 months to replace it (this was at the high point of the pandemic and they were swamped...) By that time I'd upgraded to a Moonlite 2.5 inch. I LOVE it, have not had anything but good results with both visual and imaging. I like the scope very much, but the focuser is a weak link, I think.

 

I also have an ASIAIR, and if I went to an EAF, they do not mate out of the box w the Moonlite, but a bunch of guys make simple brackets, some sell them, and the Moonlite works just great with the EAF, so they report. 

[DaveDE]

I have that scope as well. I'm still trying to get good field flattening performance out to the edges with the Hotech flattener and my ASI2600 APS-C size imager. I have not been able to achieve that yet and am still experimenting with different back focus distances and need another clear night to get it sorted out one way or another.

 

I can almost say with surety that there is no way this telescope and the Hotech flattener will work very well with a full frame sensor. For that to work, a larger aperture field flattener would be required, perhaps the William Optics 68III. I wish I knew if that flattener would work with this telescope. It's an expensive gamble and time sink to try it without knowing ahead of time.

 

The 2.5" focuser is definitely a weak link and I'm contemplating upgrading to a feather touch (or Moonlite) and will do that if I can get a flattener to work well with my APS-C sensor. If the 68III and a feather touch could get this rig up to full frame, that would be awesome but I'll settle for APS-C. I'll never buy another refractor that doesn't have a dedicated field flattener designed for it from the get-go. Too much frustration and brain damage.

Edited by DaveDE, 21 January 2022 - 11:55 AM.

[Lalanke]

I have that scope as well. I'm still trying to get good field flattening performance out to the edges with the Hotech flattener and my ASI2600 APS-C size imager. I have not been able to achieve that yet and am still experimenting with different back focus distances and need another clear night to get it sorted out one way or another.

 

I can almost say with surety that there is no way this telescope and the Hotech flattener will work very well with a full frame sensor. For that to work, a larger aperture field flattener would be required, perhaps the William Optics 68III. I wish I knew if that flattener would work with this telescope. It's an expensive gamble and time sink to try it without knowing ahead of time.

 

The 2.5" focuser is definitely a weak link and I'm contemplating upgrading to a feather touch (or Moonlite) and will do that if I can get a flattener to work well with my APS-C sensor. If the 68III and a feather touch could get this rig up to full frame, that would be awesome but I'll settle for APS-C. I'll never buy another refractor that doesn't have a dedicated field flattener designed for it from the get-go. Too much frustration and brain damage.

Thank you for the valuable info. I just realized Hotech FF might not work with the full frame. Also, I'm trying to understand the advantage of true 3" feather touch over standard 3" for this scope. 

[DaveDE]

I just noticed that you were planning on using the Starizona Apex ED reducer/flattener. That unit is only rated to APS-C as well and not sure how well it would even perform at APS-C. Maybe Starizon has some spot data available for that unit, at least for a given telescope. I guess I'd like to know if it's better than the 0.7 reducer/flattener from Explore. But, first and foremost I want a x1.0 flattener. By the way, I read somewhere that Starizona is working on a full frame version of the Apex ED. You might want to check with them. I'd love to know if that would work well with the ED127 but I'd probably have to buy it someday and try it to find out.

 

 

As far as I can tell, the "true 3 inch" is a bit beefier than the 3 inch and can handle a bit more weight although they both appear to handle plenty. Both are compatible with the ED127 tube adapter. The 3 inch has threads on the draw tube that are compatible with an adapter they offer as an option for the WO 68III. I think the true 3" only has 2" or 3" visual backs available for the draw tube. They also say "The difference between the FTF3035 focusers and the FTF3235 focusers is that the FTF3035 focusers cannot accept a 3" accessory so if you are wanting to use a 3" accessory, you will need to use focuser FTF3235".

 

Here's a guy that has the True 3 inch on his with a Hotech that I think also uses an APS-C camera:

 

https://www.astrobin...users/riot1013/

Edited by DaveDE, 21 January 2022 - 02:12 PM.