Thinking about what is happening with the light, you won't really find primary mirror tilt with a led in a cap at the focuser its not directional its broad beam
Primary mirror not central? mmmm still the beam spreads its not directional it doen't give you a clear cut measurement. Use a set of vernier callipers if you are very worried about it and measure the distances.... how can you be wrong ?
If you want to see if your truss's are stright eg the tubes are aligned get a piece of string.thread it past the primary mirror (use a small paper clip tilt the tube and slide it down) hold it taught, if your tube is out you will instantly see it not guess because the string should touch the tube all the way down if its bent it will either touch it in the middle or on the ends with a gap that can be seen. if its in the mm range. don't worry about it the collimation routine will take that up. This is how you would align the rear sproket to the front sproket of a push bike or even a motor bike.
A ruler will tell you if your spider vanes are straight much more reliably and quickly than a few pieces of baking paper laying over it
I commend you on trying to find a handy tool but yeah we have the tools already that do the job very well.
Brendan
Quote:
Originally Posted by tilbrook@rbe.ne
Hi, Ray.
Your idea works a treat!
Here are two images of the 16", it shows I think?
1.Primary Mirror tilt.
2. Primary mirror not central, although I measured and it is central to the box.
3. Most likely, my trusses are slightly off and I'll need to adjust them.
In any case it's ggoing to be a lot easier to work out the problems now.
Thanks again.
Justin.
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