Advice from Quark users who have tried it in front of the diagonal

[Paz]

Have any forum members used the Daystar Quark in front of the diagonal?

I am looking at all my bits of 1.25"/2"/T2/etc contraptions (I seem to have accumulated an unhealthy amount of such bits) and coming up with a set up putting the Quark first. This is driven by the precariousness of having a Quark and binoviewers after the diagonal, which I find quite stressful.

My main thoughts were will it result in clipping the light cone having that little blocker aperture so far forward, and if it is clipping will that mean less aperture, slower focal ratio and  possibly introduce some scatter, and the issue of causing even more magnification.

I use it mostly with a 102mm f7 and sometimes with a 72mm f6.

[Paz]

To update I've had a go and ended up with quite an unusual set up needing a 2" extender plus 85mm of focuser travel to get focused.

I've never had a focuser hanging out that far, I felt it was almost an abuse of my scope but the views were really good and with a big enough sweet spot so I stuck with it.

I seem to have just swapped from worrying about a ridiculously tall stack to worrying about a ridiculously long backfocus.

I think it might be clipping and doing so slightly asymmetrically or the alignment is struggling when the focuser is given that much to do as the view reminded me of how it looks if I use an aperture mask (i.e. seeing finer details) and rather than a dim area inside of the field stop all round instead there was a very dark area and no clear field stop at one edge (the bottom) but a clean and clear field stop at the opposide edge of field.

[Peter Drew]

Using the Quark in front of the diagonal will advance the Barlow effect of the Quark and be responsible for the increase in back focus.  Also the use of binoviewers will also increase the distance between the Quark Barlow and the eyepieces, further increasing the back focus and the magnification.  The asymmetry of the clipping is most likely due to sag from the long extension.   🙂

[Paz]

2 hours ago, Peter Drew said:

Using the Quark in front of the diagonal will advance the Barlow effect of the Quark and be responsible for the increase in back focus.  Also the use of binoviewers will also increase the distance between the Quark Barlow and the eyepieces, further increasing the back focus and the magnification.  The asymmetry of the clipping is most likely due to sag from the long extension.   🙂

I've pored over the optical chain and I will get a quark-to-t2 connector that will shave off 10mm or so between the quark and diagonal, I can also possibly get away with a lower profile t2-1.25" adapter between the diagonal and binoviewers and save a little there if I have a rummage through what I've got lying around. That will hopefully make things more civilised!

[astro_al]

This was my configuration when I had a Quark. Still pretty unwieldy with the binoviewers added though.