[Shiraz (Ray)]

hi Fernando. This looks a lot fuzzier than I have seen - what light source and type of paper did you use? I found that a LED and baking paper worked best.

The physical alignment is not perfect, but its not too bad and I would think it should work OK for planetary as is if you collimate it with this setup. Mine was a lot worse than this when I started, but it still worked OK for planetary.

If you want to tidy up the alignment further, I would check that the centre spot is actually central before you do anything else. and of course re-collimate if you change anything.

Issues that will increase stray diffraction and that could be a problem in long exposure imaging are:
1. the spider is not straight and you could adjust it to pull the secondary up towards the focuser a bit. That will help centre the beam a bit as well.
2. the focuser is intruding into the beam a bit - was it wound right in or something?
3. the secondary shadow is not circular - the secondary is twisted which probably means that the hub attaching to the spider is not quite pointing straight down the tube. the collimation process has required that the secondary be twisted to bring it back to a roughly central position.
4. the light column is not quite central, so you will have the OTA intruding into the light column in some parts of the field - not a major issue for planetary, but you could tweak it up by shimming the focuser and/or moving the secondary in/out of the tube.

I have no idea why there are two shadows from parts of the spider. If you use a single led source, do you still see the double shadow?

did this agree with your interpretation? regards ray