Re: dob tube length vis a vis CMOS imagers
¿ªÔÆÌåÓýHi Gary, If I remember correctly I did not need to shorten my truss poles initially when I was using my camera only (asi294MCPro) and cona corrector. It was only after I wanted to try using a nexus focal reducer that I needed more back focus. I¡¯m using an 18¡± f4.3 dob that has a low profile feather touch mounted to the astrosystems filter slider. I had a falcon rotator that I had wanted to add into the image train but it needed so much more back focus when added. It would have made the truss poles extremely tight where they mount to the upper cage due to even more shortening so I sold it. One thing you also should check is to see if a larger secondary mirror will help provide a more fully illuminated image circle. I upgraded my secondary from a 3.5¡± to a 4¡± and I did notice images improved a fair amount. Mike On May 13, 2024, at 9:03?AM, K9RX - Gary via groups.io <amateurK9RX@...> wrote:
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Mike