BORG 55FL F3.6 with Feather Touch Focuser

As mentioned here several times, FTF setup in 55FL F3.6 is very challenging. After playing around while changing the combination of many parts, I have concluded this looks best possible configuration.

ftfs2555 + 7680 + 7026 + FTF-BORGII + FTF-M57(replaced 7459 with 7901) + 7880

Original FTF-M57 comes with two 7459 at both ends of FTF drawtube. A rear 7459 had to be replaced with 7901 for shorter light path.

Now there are some issues.

  1. As shown, clamping section for tube ring is very narrow. 7026 is 25mm long. Probably there is only 38mm long including both adapters.
  2. Another challenging issue is how to mount the scope without interfering with a plate and the tracking mount. One idea I came up my mind is to use a following camera rotator. This rotator raises an optical system up. So this gives a plenty of room for plate or mount. This should be very convenient for DSLR users since the above system doesn’t include 7352 – M57 rotator, which was too long to reach the focus at the infinity.

cr110But I have no specific idea how to set coolded CCD camera bodies. That’s what we have to carefully look into more. Probably it might go the usual way to clamp a tube. 2 x 7085 fits.  AOK Swiss makes following the clam-shell type. This looks good one too.

aok

Finally take a look at ST8300 chip’s field of view by 200mm focal length.

55FL(オリオン大星雲・馬頭星雲 Hα ST-8300M 10分x28)s2BORG 55FL F3.6 + SBIG ST-8300M with Ha filter, 10 minutes x 28 taken by Naoki Nakanishi

And field of view by full frame sensor.

ngc1499_ic348_d810a_55fl-200_lprn_hdWith Nikon 810DA by Yutaka Numajiri

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~ by tedishikawa on January 21, 2016.

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