Eyepiece Projection for the Planets & New BORG 55FL Astrograph

One of reasons I picked ASI 183MC was for the planets. Yes, 2018 is the Mars year. So I start checking my gear to make all ready for practicing. A key component is BORG eyepiece projection adapter #7410, which is really versatile and flexible. I love this concept.


With my favorite imaging eyepiece – Pentax XP-14


Eyepiece to be closest to the sensor




Features are

  • Virtually allows to use any 1.25″ or 24.5 mm (with an adapter – # 4605 as shown) eyepiece as long as the eyepiece head diameter is 53 mm or smaller. Eyepiece length is not issue if a M57 extension tube is in. (I don’t think there is big head eyepiece suitable for planetary imaging)
  • Adjustable image size by sliding an eyepiece barrel back and forth.
  • Eyepiece holder is sold separately. It’s convenient for quick eyepiece swap.
  • Virtually fits any camera available in the market, T-mount, C-mount, DSLR and mirrorless etc.


I’m curious how Fuji X-trans sensor and image processor perform for planetary imaging. I will test and see in the practice round, and my favorite solar camera – Lumix GX-8 (20MP) as well.

Probably 14mm eyepiece is not short enough with 107FL for the Mars.  I will go with try-n-error way. Vixen HF should be a good eyepiece. But must be too much. Also I have to keep two of HFs for visual observing with a binoscope. I’m looking forward to observe the Mars through binoscope at high magnification.

About 55FL astrograph, challenging part for short focal length scope is the proper mechanical length. Shorter, harder, and this is most challenging system since the focal length is only 200 mm.

I noticed AOK Swiss had a following Mini BORG-to-FTF unit.


A current unit shown above is too long to reach focus. But I’m sure technically it can be shorter. Present 55FL FTF package set doesn’t look good completion,  hard-to-adjust weight balance and no camera rotator. But this solution should clear up those negative factors. I will ask Beat at AOK to make a short version for astrograph set.

Once a new unit is ready, I will announce here. I hope all will work out as expected.


~ by tedishikawa on January 26, 2018.

4 Responses to “Eyepiece Projection for the Planets & New BORG 55FL Astrograph”

  1. Hey Ted I like this what items do I need to mount it on my Sony A7s and cost please.

    Alan Sent from my iPad


  2. Hi Ted, have you ever used eyepiece projection for galaxies? Or is the image too dark? Do you think there is an advantage for eyepiece projection compared to a PowerMate or Borg teleconverter? Do you need a flattener in your imaging train as well?

    • Scott,

      I’ve never tried to use eyepiece for galaxies. It should be too dark, or slow.

      For small planet like Mars, I’m sure teleconverter is not enough much. Definitely you need an eyepiece to enlarge the image scale.

      At least you will need 20,000 mm overall focal length, or hopefully more. Let me test around to see realistic number.


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