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Best EP that eliminates colour aberation? (1 Viewer)

woodhornbirder

Well-known member
AM torn between going for a xw10 or a televue nagler, both costing approx £150, FOV is larger on the nagler, but both are top quality.

Actually the nagler is 7mm so is slightly more powerful. I assume 7mm is ok on a pentax 80mm, or would that be smidgen past the "sweet spot" ?

FAr as i am aware boththese ep use lanthanum glass in the design.

Sadly i cant afford both. Have to make a tricky choice!

ANy suggestions? THese are obviously ep that will pusht hte scope to the max, but should in theory produce some fab results.
 
XW10. The Pentax 80mm has a true aperture closer to 70mm at typical birding distances. 50-60x is about the most the scope can take.
 
I use an XW10 on my PF80-ED and it is an excellent combination.

The big issue with the Nagler for me would be the eye relief, even if you don't require glasses the Pentax will be more comfortable to use for long periods of time.

Mike
 
It is an engineering design "feature" of the 80ED. As you focus from infinity to close focus distance the focuser intrudes into the light path reducing the max effective aperture from ~78mm at infinity to ~67mm at near focus. This was first documented by Henry Link and later verified by myself in this forum if you want to search for the threads.

Rick
 
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