The chart below shows the effective magnification when spacing is introduced between the Barlow lens and image plane of your camera or eyepiece
TeleVue Barlows use multi-coated high index glasses for optimum aberration correction, exceptional contrast with virtually no light loss.Observed performance is aberration free, even when tested with f/4 scopes.
They even improve non TeleVue eyepieces and telescope performance.
Compromise image quality in any part of the optical chain and you’ve compromised every part!
TeleVue product design and execution deliver consumate satisfaction.
Every TeleVue Barlow must pass the same rigorous f/4, full field testing as all TeleVue eyepieces.
Offered in a 2x magnification, the Big Barlow is ideal for Newtonian scope owners.
It will be parfocal with both 2″ and 1 1/4″ eyepieces in this application.
Features include threads for 48mm filters, captive lock screw and full milti-coatings.
Note: The Tele Vue 2x BIG Barlow is not recommended for use with 2″ diagonals because it’s length prevents it from being parfocal. With some telescopes, focus might not be reached, particularly when the Panoptic interface lens is also used with it. A far better approach with no potential problems in any scope or with any eyepieces is to use the 2″ 2x Powermate (PMT-2200), which essentially includes the Pan-Barlow Interface