Explore Scientific Ed127 fcd-100 Focuser Swap

[ceefna]

Hi everyone, I have picked up a used fcd-100 ed127 with the hex-focuser. As I already have a Baader steeltrack RT focuser spare do you think it would work on this scope? Or will it suffer from horrible vignetting with being 2" as apposed to 2.5".

Physically they are quite similar in size and the Baader has plenty of focus travel. I am also going to use the 3" 0.7x reducer that came with the scope if that will make a difference to illuminated field? Camera is a zwo 1600 pro 4/3.

I would appreciate some insight if you think it's a waste of time before I knock up an adapter on the lathe.

 

Many thanks

Ceefer

 

[Adam J]

2 hours ago, ceefna said:

Hi everyone, I have picked up a used fcd-100 ed127 with the hex-focuser. As I already have a Baader steeltrack RT focuser spare do you think it would work on this scope? Or will it suffer from horrible vignetting with being 2" as apposed to 2.5".

Physically they are quite similar in size and the Baader has plenty of focus travel. I am also going to use the 3" 0.7x reducer that came with the scope if that will make a difference to illuminated field? Camera is a zwo 1600 pro 4/3.

I would appreciate some insight if you think it's a waste of time before I knock up an adapter on the lathe.

 

Many thanks

Ceefer

 

If its the Explore scientific then its F7.5 and you will have no problem with the 2 inch focuser and that sensor. The problem i see you may have is insufficient travel on the Baader focuser as I believer that the original focuser requires the use of extension tubes to reach focus and is configured that way to allow the use of bino-viewers, have you accounted for their use? 

I am not sire about how you would connect a 3 inch reducer to a 2 inch eyepeice holder?

Adam

Edited August 26, 2020 by Adam J

[ceefna]

Hi Adam many thanks for your reply. I have got the 2 Focusers side by side and they have pretty much the same travel. With the ES 3” reducer You get a  m68 adapter to screw it straight to the STD hex focuser draw tube. The baader draw tube has a m58 dovetail or a m55 thread so I can easily make a m68 to m55 adapter to screw the reducer on. From what I have read it was not enough inward focus that stopped the early ED127’s achieving focus with the 3” reducer but I can make my steeltrack adapter (m88 dovetail to m130x1) any length I want so the draw tube is in the same place when wound all the way in. I wasn’t sure if I would have an issue at f5.25 with the reducer?

 Thanks again

Ceefna

[Adam J]

22 hours ago, ceefna said:

Hi Adam many thanks for your reply. I have got the 2 Focusers side by side and they have pretty much the same travel. With the ES 3” reducer You get a  m68 adapter to screw it straight to the STD hex focuser draw tube. The baader draw tube has a m58 dovetail or a m55 thread so I can easily make a m68 to m55 adapter to screw the reducer on. From what I have read it was not enough inward focus that stopped the early ED127’s achieving focus with the 3” reducer but I can make my steeltrack adapter (m88 dovetail to m130x1) any length I want so the draw tube is in the same place when wound all the way in. I wasn’t sure if I would have an issue at f5.25 with the reducer?

 Thanks again

Ceefna

I would not think so, not with that sensor size anyway.

Adam