Quark questions

[robertm]

Following on from my PST issues thread I’m looking at buying a Quark which I’ll primarily use with a Bresser AR102 (102mm f9.8). There seem to be a number of models to choose from but if I’m getting this right, the Chromosphere version is the one as it’s the most versatile. With the Chromosphere there are two versions; one with a telecentric Barlow and 12mm BF optimised for f/4-f/8 refractors and a slightly less expensive version with a 25mm BF but no Barlow optimised for f/15 and longer refractors (plus Maks and SCTs). The AR102 is in between these ranges and that poses a dilemma.

My question is which version would be the best to go for given that I would try to double stack it with my PST etalon assembly? Also the supplier does check each unit so is there anything specific I should ask them to look out for?

Any help gratefully received.

Robert

[Dennis]

Both models - combo and regular cost the same. with the combo you will be more flexible because you can adapt the telecentrics to the f-ratio of seeing and telescope. But you will need a telecentric and no barlow, which means extra cost. Baader is one company that offers real telecentric systems of 2x,3x and 4x. Doesnt mean that you cant use a regular Quark with your scope at f/10. Im using f/10 too on my sct with a standard Quark and if seeing is good it works good - depends on the camera and sampling.

In a non double stack scenario i would get a different telescope (achromat) with f/7 or better f/8 and get the standard Quark chromosphere.
Since you want to double stack i cant tell what would be better.
My "suppliers" checked on each unit too, nevertheless all they delivered was non acceptable units. The one im using is from a private person.

[pupak]

I would buy the Quark combo chromosphere. It has an 18mm large BF, so it can work in a telecentric beam even with cameras with a 16mm chip. It will work well for F10 with the Baader TZ3 or the ES 3x extender.

[robertm]

Great stuff and thanks for the useful insight. It looks like the combo with either TZ3 or ES 3x.

Many thanks
Robert