I forgot having made FLI PDF adapters for BORG scopes long before. One of BORG users who is interested in integrating PDF into his 90FL system has let me recall the long inventory of these adapters.

Here is the ones. It comprised of 2 or 3 pieces.


A middle long tube is only needed for previous ED F4 reducer. So it doesn’t require for current reducers. Basically the light path of front and rear adapters are designed for quite similar to BORG helical focuser – 7835. So it won’t be too long or not too short.


I borrowed PDF from a friend – Jim today and tried to set with BORG 90FL. The key for success should be the weight balance. Total weight of camera/CFW and PDF should be much heavier than the objective lens. So how to adjust, that should be the point. Front is M68.8 and rear is M57. At least this is good up to full frame sensor cameras.

PDF’s ID has 89mm. So it looks still fitting a future larger format super reducer too. Yes, front and rear adapters must be lager than current ones though. At least reducer’s lens barrel can go through PDF inside.




~ by tedishikawa on October 11, 2017.

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