Quote:
Originally Posted by Joshua Bunn
Thats very interesting, its not only in the blue filter to, the red filter is showing just as much elongation in the top right corner. Did you refocus between filters?
Does this filter wheel and filters work well with a different scope?
|
Most definitely interesting to be sure and puzzling
To respond to your points:
- Yes, my auto focus routine is set to refocus between filter changes.
- Prior to switching to the FRA300 I was imaging with a Canon 200mm prime lens and had not noticed this level of aberration in one colour channel. Just to be sure though I will go back and check the data.
- Agreed that the red filter has obvious tilt in the top right corner. And, as Ken points out, there is a slight shift in the green channel as well. The difference here though is that the red channel shows what I would call a classic tilt in that the issue is quit apparent in the top right but the rest of the field is ok. Also, the star shapes are elongated as opposed to the ‘triangular’ shaped that is evident in the blue channel. From my experience, the triangular shaped stars only come from collimation errors or pinched optics. Again, this last point brings up the conundrum of why is one channel affected more than other?
Notwithstanding all of the above, I am going to tweak the tilt adjustments to see if this evens the channels out and then re assess where I take things from there.