I’ve posted before about how much I like my c11 for night vision use. In conjunction with a reducer and 55mm plossl I can get an effective f3.5 speed for nice real time views with good image scale. However, at my last outing with the c11, it struggled with my 3nm ha filter and my 5nm filter delivered nicer results.
We’ve had weeks of clouds in the UK but this evening at last we had a clear sky. We arranged a local Astro club meet up at our usual local light polluted site (sqm 19)!
I set up both my Tak fsq85 and c11 edge side by side on my panther mount, to give widefield nv views with the Tak and more detailed views with the c11.
I had a nice session on the usual suspects (horsehead, flame, rosette, pac-man, cocoon, wizard, bubble, California, veil, monkeyhead, butterfly etc), switching between the Tak and the c11 depending on the size of the object.
My c11 edge has the special edge reduced attached to it so bringing the f ratios down to 7. Using a 55mm plossl gives a effective f3.3, nice but I’ve always hankered for a bit more speed.
I was using my 0.75x gso rc reducer with my Tak and decided to experiment by using this reducer in the c11 edge. I was t expecting it to work due to the need for a special reducer, but to my surprise it worked great, giving lovely sharp stars and nebulae detail. M42 was incredible.
With an effective speed of f2.5 (getting close to my f2 target for visual observing), this stacked reducer setup may well be my most used nv setup going forward - it was brilliant!