TeleVue 5x 1.25

TeleVue 5x Powermate T-Ring Ready.
  

I thought you might be interested in the development of this project:
  

Barlows amplify the power of a telescope. They can be considered "focal reducers" for eyepieces, or "focal extenders" for objectives.
  

Terence Dickenson, in his Barlow test report in Sky and Telescope, July 1997, says: "Technology has erased the old objections. A modern Barlow will not degrade your telescope`s optics. Anyone telling you otherwise is using outdated information. Moreover, the highly regarded Nagler eyepieces and their clones have built-in Barlows, ample evidence that the lens is not some detrimental intruder." Thanks, Terence, for laying the myth of the degrading Barlow to rest.
  

Barlows do more than just increase magnification; they also retain eye relief (or in the case of long focal length eyepieces, actually INCREASE eye relief). A high quality Barlow must be properly designed and manufactured in order to avoid compromising a telescope`s color correction and spherical aberration correction. The "invisibility" of Tele Vue`s 2-element Barlows have been noted in test reports in the astronomy magazines.