I'd guess that this would be a wonderful system for one-shot-color imaging under a dark sky. However, the short backfocus (25mm) for the camera suggests that this would be kind of a "bear" to operate for narrow band or RGB filtered imaging. But, maybe not any more so than your EdgeHD with a HyperStar (you'd have to look to see what kind of backfocus is available on the HyperStar). I guess if you wanted full automation you could limit yourself to one filter per night (and use the built-in internal filter location that is provided on the RASA, but that's assuming that any narrow band filters become available that fit that internal filter location).
Otherwise, the thinnest filter draw that I current own is 15mm thick (from Teleskop Service) and if you assume that the stated 25mm backfocus is "real" and includes the proper and short t-threading then that leaves only about 10mm for the spacing between the filter drawer and the camera sensor. I guess that would work on the ASI1600 but that would also require a very short female-to-female t-thread adapter to do the gender change between the filter drawer and the male threads on the ASI1600 camera body. Unfortunately, the shortest such adapter that I know about is 10mm thick and given the minimum 6.5mm backfocus available on the camera body that would exceed the remaining 10mm (since you'd have 6.5mm on the camera body itself and an additional 10mm for the gender changer, so 16.5mm of total spacing). Actually, I don't think you could make that work since you probably need at least 6mm of threading on the gender changer to allow you to thread both of the male ends into the adapter. So, 6.5mm from the camera and 6mm for the gender changer and you're already beyond the available 10mm.
In any case, at some limit you'd probably get better performance from the RASA and Celestron claims just that on their website.
When compared with “Hyperstar SCT” systems, the RASA 8 provides better optical performance and field illumination.
The focuser could be much, much better on the RASA and it would be nice to have the built-in fan for cooling.
[UPDATE]
It just occurred to me that you wouldn't have to use a filter drawer to mount your filters (at least for a camera like the ASI1600), you could just use one of the thin t-adapters that take an internal 1.25" mounted filter. Of course, that would mean that you'd have to unscrew everything to change your filter but it could work.
In fact, ZWO makes just such a product that you could use with the ASI1600 camera.
https://astronomy-im...-filter-adapter
What you'd do is use the 10mm t-thread nose piece that comes with the camera (basically the thick gender changer I mentioned earlier) and attach that to the male threads on the camera body and then you'd screw the above filter adapter into the female threads of the nose piece. That would mean you'd use 6.5mm + 10mm ≈ 16.5mm of the available 25mm of backfocus.
[/UPDATE]
Edited by james7ca, 06 September 2018 - 03:46 AM.
The more I read up on the RASA, the more tempting it is to go that route.
