Quote:
Originally Posted by Startrek
I’ve noticed over the last week that my AP images of larger stars in the FOV have dual diffraction spikes only on one axis ( east / west ) where the spike starts off single from the star core and then slightly splits into 2 on a very tight angle away from the core ( it’s just noticeable)
Could it be that one axis of my spider vanes are not at 90 degrees to the adjacent
I don’t think it’s collimation as I use a Cheshire and laser collimator and visually get it spot on,totally concentric in secondary and primary with a bulls eye in the middle
Scope is a Bintel GSO 6” f6 newt
Any advice or comments appreciated
Cheers
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Judging by the picture you need to loosen the screw on the bottom spike a little and tighten the top one to bring the east/west vanes into a straight line. The cause of spikes that split more as you go further from the hub is the two opposing vanes not making a straight line, which then means that their secondary reflections are also showing that deviation but in the opposite direction..... (a 3-vanes spider is the ultimate extension of this as its vanes reflect in the same manner to show 6 diffraction spike)
(I am not discussing the offset look of the secondary shadow etc, just the alignment of the vanes)