BORG 55FL F3.6 & BORG 2″ Compression
This is 1st test shot by Rick Stevenson in Australia after he was patiently waiting for 55FL F3.6 system a couple of months. Take a look at his beautiful wide-field Ha shot.
Here is his comment. First test is attached. ASI1600mm camera, Chroma 3nm Ha filter, just under 8 hours of 30 sec subs on a Star Adventurer mount and some very quick & dirty processing (no flats yet…)
The system achieves 75% illumination strength at full frame corner. So I guess it might have around 90% at entire 1600 chip. This super high contrast result seems to show us this scope’s biggest advantage along with the speed (F3.6) over the conventional telephoto lens. Yes, I love my 55FL F3.6 too. One of most favorites. Small scope and small mount, but no compromise optical performance. This is the concept for this scope.
He selected a following system.
One index mark of 7761 helical focuser indicates 90 micron. So it might allow to manually control 20 micron by 20 micron. This repeatable minimum step should be useful for re-focusing filter by filter if desired, without monitoring the screen.
Rick, thank you so much for your patience this time. I’m glad you finally got what you have been long waiting and it looks performing as expected. Enjoy astro imaging with this powerful small scope.
We are shipping more 55FL F3.6 these days. So I’m looking forward to seeing other 1st light from others too.
A following is new M57-2″ compression ring holder. Yes, nothing new and special in the market. But believe or not, BORG never had 2″ compression type. Still not. So I decided to make it as Hutech. Here is the one.
As usual, it has M57 at the objective side. So it fits all of BORG systems like BORG genuine parts. I plan to add this item as default for BORG visual sets from now on. And yes, it is available separately, which allows to simply replace current holders with this one.
BTW, this is Hutech M57 Rack & pinion.
With 2″ compression ring. M77.6 at the objective side, which allows to attach directly Series 80 tubes
This unit will be first available as a focuser of 55FL F3.6 system. 1:10 knob allows to smoothly and precisely control focusing like Feather Touch focuser.
DigiBorg 