Hello,
Thanks again for the illustrations Jason. I can see using the 1st picture from the left where the mirror is angled at 45 degrees is why the centroid of the mirror moves forward to catch the light at the edges. To have the centroid in the middle both mirror faces would have to face one another. ie. cats and casses right., otherwise it would be as you say and the mirror would go back up the ota and some of the secondary mirror closest edge (when viewed from the focuser) would not catch any light.
But I'm not all that convinced yet and am still out on this collimation thing. Your picture is nice but is maybe a little over exaggerated for basics. I would like to see a more detailed drawing with something like Autocad with a bit more realistic measurements. I have access soon so maybe I'll do a bit of research myself.
I guess that the light cone would also shrink as you go further away from the primary and as long as the light remained within the boundary of the edge of the secondary on the far side (when looking from the focuser) and that it did not pass the focuser (which it can't if I'm not mistaken if you want to view anything) no light would be lost correct?
My only concern then would be the axis that the light then travels into the focuser but judging by the first illustrations you sent (one on the left) it shows the axis as still in line and the primary fully shown.???
My only problem with that set up is I don't have enough mechanical room to move the mirror back to get to the center point with some ability to adjust it.
Therefore it seems as if both cases are plausible as long as I could get enough movement with the secondary.
Is another problem that by using a smaller cone/area (when moving the secondary back up the ota) of light that something is changed or diminished in anyway or will this only affect the usable range of the focuser?
By the way I'm not trying to attack you in anyway just trying to understand it fully and would appreciate any comments that clarify any of these points. I also encourage anybody else to comment as well. Thoughts please.
Regards
Simmo
