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3/06/2017

Sirius A & B Seeing the Pup


I believe I have written on this before, and the sketch below is from a year ago, but I never posted it. It shows the view in my 17.5" dob with the curved spider vanes and how easily the pup is seen in that scope. In both my 14" and my 10" which have 4 vane spiders, I have seen the pup or Sirius B before, but the diffraction spike in some ways helped, and in other ways subtracted from the view. I will say that for me, the curved spider, as long as it is attached correctly and doesn't hinder collimation or holding collimation, makes a difference in the view on this object, and on other objects. For me it is not that the diffraction spike is gone, that light is still in the field of view, it is simply spread out and that to me is the difference. A bright star next to a deep sky object like a galaxy does the same thing. It allows the main object, the galaxy to be viewed without the diffraction spikes.

Now having said that, I have used my diffraction spikes on my other telescope to guide me in to faint objects and in this case, to guide me into seeing where the pup is.  So to curve or not to curve should not be based on the view, it is a consideration but it is based on the fact on whether the scope can maintain collimation with the vane in the upper ring or structure.  In my case in my 17.5" I needed to a make my own adjustments to how the spider connects to the ring to secure the spider and stop collimation shift.  Not a problem, that is why I have the scope I do, I like to tinker and play and it makes the scope more mine than not.  If you don't like to tinker, then get a scope you don't have to mess with. So, here is how Sirius looks like from my 14" and 10" scopes.


The above is Sirius A and B (the Pup) from a 14" with 4 vane spider. 


Above is Sirius A & B in my 4" refractor, an Explore Scientific AR102. 


The view of Sirius A & B in my 17.5" dob with curved spiders.