Focus problems

[phattanglo]

I tried to use my explorer 150p to let my grandson observe the moon and found I could not achieve focus.

For reasons I won't bore you with I have not used my scope since I dismantled it to flock the tube.

It's obvious I have gone wrong in the reassembly as I could only achieve focus by holding the eyepiece above the focuser.

I have adjusted the primary as near to the end of the tube as possible but to no avail so run out of ideas I'm afraid.

 

[PeterCPC]

Have you tried with a Barlow?

[phattanglo]

Hi Peter, no not tried a Barlow yet.

Prior to my hamfisted bungling all was fine.

I'm assuming at infinity the focuser should be racked in pretty close.

The only thing altered is the addition of a Revelation Astro centring adaptor to replace the standard 1.25 holder but I seem to think it was about the same height.

I'll try to rectify this but if all else fails I'll go back to the original eyepiece holder and see if the new holder is the problem or if I need an extension.

Edited April 18, 2021 by phattanglo

[Ricochet]

2 hours ago, phattanglo said:

The only thing altered is the addition of a Revelation Astro centring adaptor to replace the standard 1.25 holder but I seem to think it was about the same height.

This will be your problem, they are quite different heights I think. You need to put the 2" extension in the focuser and then put the self centring adaptor into that. If you put the self centring adaptor straight into the slightly larger than 2" hole at the top of the draw tube your eyepiece will be too close to focus. 

[phattanglo]

I've come home now but next time I go to my holiday home I'll check.

Though I'm fairly sure there is a black adaptor between the draw tube and the new self centring holder.

I would appreciate it if someone could post a pic of the correct way to mount the self centring holder.

So I've just gone in my loft to my box of astro bits n pieces and what do I find, the original 1.25 holder and the original 2" holder. No wonder it wouldn't focus.

What a tool!

 

Edited April 18, 2021 by phattanglo