Leica/Zeiss zoom/VIP revival thread

[Deadlake]

Gerry you might want to checkout the revised TMB APM Barlow, meant to give sharper stars at the edge then the VIP you are using, also very good used with Bino’s as well.

[Don Pensack]

8 hours ago, Deadlake said:

Gerry you might want to checkout the revised TMB APM Barlow, meant to give sharper stars at the edge then the VIP you are using, also very good used with Bino’s as well.

It's only a thread-on Barlow lens, though, which might be an issue in a star diagonal for all the 2"/1.25" eyepieces out there when used as 2" eyepieces.

[Deadlake]

3 hours ago, Don Pensack said:

It's only a thread-on Barlow lens, though, which might be an issue in a star diagonal for all the 2"/1.25" eyepieces out there when used as 2" eyepieces.

It attaches to the bottom of the APM zoom, sold as a pack.

Needs push fit adapter for the 1.25" barrel.push fit adapter 

Edited April 1, 2023 by Deadlake

[John]

2 hours ago, Don Pensack said:

It's only a thread-on Barlow lens, though, which might be an issue in a star diagonal for all the 2"/1.25" eyepieces out there when used as 2" eyepieces.

In my case I had a chopped down barrel on my VIP barlow, to avoid just that. I think that is the approach being used that in the photo that @jetstreamposted in the original post in this thread.

Edited April 1, 2023 by John

[Don Pensack]

11 hours ago, Deadlake said:

It attaches to the bottom of the APM zoom, sold as a pack.

Needs push fit adapter for the 1.25" barrel.push fit adapter 

The APM Zoom requires only a bit of in focus when used as a 2" eyepiece.

When used as a 1.25", it requires massive amounts of in focus.

I regard it as a 2" zoom.

Unless the scope has a lot of in travel available, that means a zoom on its bottom end may likely strike the diagonal mirror in a star diagonal.

 

[Deadlake]

4 hours ago, Don Pensack said:

The APM Zoom requires only a bit of in focus when used as a 2" eyepiece.

When used as a 1.25", it requires massive amounts of in focus.

I regard it as a 2" zoom.

Unless the scope has a lot of in travel available, that means a zoom on its bottom end may likely strike the diagonal mirror in a star diagonal.

 

I think Sixela has work arounds with this for this (in the thread on CN) so the bottom of the Barlow is flush and will not hit the diagonal. 
 

However how much back focus is required, that’s an interesting question.

Edited April 2, 2023 by Deadlake