Sunday, January 19, 2014

tested orientations

Conducted, with a gaggle of example telescopes, field of view tests from SkyTools. Each type of telescope was configured with four possible settings of the Left/Right and Up/Down settings. I also added a DSLR camera to each configuration.

Activated binoculars first. Greatly magnified the view. I saw a "natural" view, if I were to view the celestial object directly. This is also how the Interactive Atlas view is presented, of course, in its default state. That is, the Flip (vertical) and Mirror (horizontal) buttons are not active.


Now a token refractor with Normal and Normal settings.


Next the same refractor is configured as Normal and Flipped. As expected, the image has been flipped vertically. Notice ζ (zeta) Orionis is now at the bottom. Yet σ (sigma) Ori is still on the right.


Next up is a Mirrored and Normal configuration. ζ returns to the top; σ is left. Typical of a refractor, SCT, or MCT with a mirror diagonal installed.


Finally, the refractor is shown with Mirrored and Flipped. It is as if the original natural view has been rotated 180° with ζ at the bottom and σ at the left. Typical of a reflector.


Subsequent tests showed the exact same results. That is, a reflector or SCT telescope choice in SkyTools did not fundamentally change the view. Somehow, I was expecting it would!

Selected the camera. At prime focus, the view is natural. ζ top and σ right. Tried all the different configurations of the refractor and it made no difference. The Left/Right and Up/Down options seem to be used for visual observing only. Not what I was initially expecting of a refractor. But technically correct. The refractor, without a mirror diagonal, would present a (180) rotated view. Which is exactly the same was Mirrored and Flipped in the software.


Now that I think about it, it all makes sense. Camera bolted to a refractor's focuser has zero reflections. Camera bolted to an SCT focuser or visual back has two reflections. And that would be the same as when one attached a camera to a Newtonian's focuser. Two reflections. And my old simple rule applies... Odd number of reflections: mirrored; even number of reflections (and zero): rotated.

The only scenario I can think of, for amateurs, where there's an odd number of reflections, is with the Fastar or Hyperstar systems. A camera in place of the secondary... How is that configured in SkyTools?!

The result of this testing, to me, shows that it doesn't really matter (other than for record keeping) what the telescope type setting is in SkyTools. It is very important though to have the Left/Right and Up/Down set perfectly.

No comments: