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Need help with my B &L Discoverer Zoom 60mm - no infinity focus. (1 Viewer)

Bino Steve

Well-known member
United States
Hi everyone. I bought a vintage Bausch & Lomb 60mm ,15x to 60x Discoverer Zoom straight through spotting scope that is in mint condition in and out. But I'm puzzled as it won't focus on the moon or stars. So no infinity focus happening. I dismantled the barrel and can see the lens move in and out. The focus ring hits the stops just fine. I'm at a loss. Anyone have experience with this model? Thanks in advance.
 
Sounds like someone dismantled it and reassembled it incorrectly.

I have had refractors where the objective was back to front.

Leica lenses completely jumbled up elements.

Questar eyepieces jumbled up. Scope didn't work.

Vivitar 600mm f/8 Solid Cat destroyed by someone messing it up.

Regards,
B.
 
I will take a look again, buy it focuses to about 600 ft then boom, done for. I tried loosening the focuser wheel Grub screws thinking it maybe was out of position and loose on the mechanism inside but it was fine and it rotates stop to stop. I'm very baffled.
 
Hi,

lots of possibilities here unfortunately...

  • mechanical issues - seeing the lens move does not mean that there is sth stopping it from moving all the way it would have to for infinity focus - is there a possibilty that the focussing lens is not quite where it should be - like a flipped lens holder or spacer on the wrong side?
  • wrong eyepiece - fits mechanically but different focal plane
  • objective has been disassembled and reassembly was not quite right (this should also result into other optical issues beside a changed focal length - I would expect the objective to show quite visible aberrations).
  • eyepiece has been disassembled and reassembly was not quite right - see above except this tends to happen unintentionally too... ask those poor souls who just wanted to unscrew the barrel of their Nagler or Ethos EPs for cleaning and then found themselves in front of a dozen or more lenses and spacers to reassemble... but rumour has it that Televue support is quite good at talking people through the correct reassembly procedure...

Joachim
 
Great tips Joachim, I will start looking further inside. It's just so mint I can't imagine it was ever apart for any reason. I wasn't sure if spotters even went to infinity, but the symbol is on the wheel. I thought about buying a 2nd one to see if same issue. Thx again.
 
Have you tried to adjust the ocular? I have several Discoverers and they all show the behavior you describe, but I can get them all to focus by adjusting the ocular.
 

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